MANUFACTURED PARTS

FIELD OF THE INVENTION

The present invention relates to methods of removing powder from parts manufactured using a powder-based additive manufacturing (AM) process, methods of modifying a surface of one or more additively manufactured parts and apparatus for achieving the same.

BACKGROUND OF THE INVENTION

Powder-based additive manufacturing (AM) techniques, such as selective laser sintering (SLS), use lasers or other power sources to sinter powdered material (typically nylon/polyamide). This is achieved by aiming the laser/other power source automatically at points in space defined by a 3D model to bind the material together and create a solid structure. The laser selectively fuses powdered material by scanning cross-sections generated from a 3-D digital description of the part (for example from a CAD file or scan data) on the surface of a powder bed. After each cross-section is +scanned, the powder bed is lowered by one-layer thickness, a new layer of material is applied on top, and the process is repeated until the part is completed. In contrast with some other additive manufacturing processes, such as stereolithography (SLA) and fused deposition modelling (FDM), which most often require special support structures to fabricate overhanging designs, powder-based AM techniques such as SLS do not need a separate feeder for support material because the part being constructed is surrounded by un-sintered powder at all times. Furthermore, since the build chamber is always filled with powder material, multiple parts can be fabricated within the boundaries of the powder bed allowing for high volume productivity.

However, after a part has been made using a powder-based AM process, it is encapsulated by an amount of un-sintered powder known as a powder 'cake' which is left to cool before being manually removed from the build chamber. The un-sintered power surrounding the sintered part is then removed manually with a brush, vacuum, compressed air gun, tumbler, blasting (e.g. with glass-based media), or the like. Said cooling and manual removal of un-sintered powder, particularly from AM parts having relatively complex geometries, is labour intensive, time consuming and costly. Furthermore, such manual methods are often inefficient and it is often particularly difficult to remove all un-sintered powder from an AM part. Additionally, much of the un-sintered powder is currently disposed of and not recycled which is costly and environmentally unfriendly. Once an AM part has been de-powdered, it is sometimes desirable to modify the surface of the AM part (e.g. to roughen or smooth the surface, depending on the application). It is also sometimes desirable to modify the surface of a part manufactured using a different process (e.g. not a powder-based AM process). Typically, modifying the surface would be achieved via manual blasting with abrasive media (e.g. metal-based or glass-based media), which is labour-intensive, time consuming and costly.

The present invention seeks to overcome, or at least mitigate, one or more problems of the prior art.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, a method of processing one or more additively manufactured (AM) parts and/or a powder cake containing one or more AM parts is provided, the method comprising: locating one or more AM parts and/or a powder cake containing one or more AM parts in a processing chamber; providing processing media in the processing chamber; and creating a swirling flow path for said processing media within the processing chamber for impacting the one or more AM parts and/or powder cake with the processing media.

Processing media (i.e. particles of glass, metal, ceramic or other material) can be used for a number of processing operations for AM parts/powder cakes. For example processing media can be used to remove powder from AM parts/powder cakes (e.g. via use of a glass- based media) or to alter the surface properties of AM parts (e.g. via use of an abrasive media such as metal or ceramic-based media).

The use of a swirling (i.e. cyclonic or vortex-like) flow path for said processing media within the processing chamber has been found to provide multiple processing benefits for the processing of AM parts or powder cakes containing one or more AM parts. The swirling processing media is able to impact (e.g. "blast") any AM parts or powder cakes located within the processing chamber from multiple directions, which reduces or mitigates the need to flip or rotate AM parts or powder cakes within the processing chamber, thereby leading to more efficient automated processing of the AM parts or powder cakes. The swirling flow path can be used to provide fast and efficient removal of excess powder from powder cakes (in order to reveal the AM part(s) within), as well as effective removal of excess powder from different faces of an AM part. A swirling (i.e. cyclonic or vortex-like) processing media flow path may also be used to effectively alter the surface properties of an AM part (e.g. by smoothing or roughening the surface).

In exemplary embodiments, the processing chamber is defined by one or more chamber walls and at least a portion of the one or more chamber walls has a substantially circular cross-section, wherein the method further comprises directing processing media along an internal circumference of said portion of the one or more chamber walls to induce the swirling flow path for said processing media.

Having at least a portion of the one or more chamber walls with a substantially circular cross-section facilitates the formation of a swirling flow path in said portion (e.g. along an internal circumference of said portion).

In exemplary embodiments, the one or more chamber walls comprise a cylindrical portion and/or a conical portion and/or a frustoconical portion and/or a polygonal portion which approximates a cylindrical portion and/or a polygonal portion which approximates a conical or frustoconical portion; optionally, wherein the one or more chamber walls comprise a cylindrical portion and a conical or frustoconical portion below the cylindrical portion.

Having a cylindrical portion and/or conical portion and/or frustoconical portion (or polygonal approximations thereof) has been found to facilitate the formation of a swirling processing media flow path (since such shapes have substantially circular cross-sections or approximations of circular cross-sections).

It has also been found that having one or more chamber walls with a cylindrical portion and a conical or frustoconical portion below the cylindrical portion is particularly suitable for generating a swirling processing media flow path.

In exemplary embodiments, the method further comprises: introducing processing media to the processing chamber via an inlet arrangement; and directing processing media from the inlet arrangement along the circumference of said portion of the processing chamber to induce the swirling flow path for said processing media; optionally, wherein the processing chamber defines a longitudinal axis, and wherein the inlet arrangement is offset from the longitudinal axis; optionally, wherein the inlet arrangement defines an inlet axis along which processing media is introduced to the processing chamber, and wherein the inlet axis is approximately tangential to the circumference of the processing chamber; and/or wherein the processing chamber and/or inlet arrangement comprises one or more baffles for inducing the swirling flow path for said processing media; optionally, wherein the one or more baffles are arranged to direct processing media along a circumference of the processing chamber to induce the swirling flow path for said processing media.

Directing processing media along a circumference of a cylindrical or conical orfrustoconical portion of a processing chamber has been found to be an effective method for forming a swirling flow path for said processing media.

Offsetting the inlet arrangement from the longitudinal axis of the processing chamber provides a simple means of directing processing media along the circumference of the processing chamber and inducing a swirling flow path for said processing media.

Having an inlet axis approximately tangential to the circumference of the processing chamber provides a simple means of directing processing media along the circumference of the processing chamber and inducing a swirling flow path for said processing media.

Having an angled ramp has been found to assist a flow of processing media into the processing chamber (i.e. via gravity), which increases the kinetic energy of the processing media entering the processing chamber, and helps to facilitate the swirling flow path for said processing media.

Having one or more baffles provides an alternative, or additional means for inducing a swirling flow path for said processing media within the processing chamber.

In exemplary embodiments, the swirling flow path for said processing media is created by inducing a flow of fluid (e.g. air) through the processing chamber; optionally, further comprising entraining processing media in the flow of fluid; optionally, further comprising introducing a flow of fluid to the processing chamber via the or an inlet arrangement; optionally, further comprising expelling a flow of fluid from the processing chamber; optionally, further comprising expelling a flow of fluid from the processing chamber through an outlet in the centre of the processing chamber; optionally, wherein the outlet comprises an outlet tube extending from an upper end of the processing chamber into an interior of the processing chamber. A flow of fluid has been found to contribute to a de-powdering process either on its own, or in combination with the processing media.

Entraining processing media in a flow of fluid (e.g. air) has been found to improve the rate at which powder is removed from the AM parts or powder cake. For example, the flow of fluid has been found to increase the kinetic energy of the processing media, and thus increase the force of impact of the processing media with the AM parts or powder cake.

Introducing a flow of fluid to the processing chamber via the inlet arrangement facilitates a swirling flow of fluid and processing media (since the inlet arrangement is configured to direct material flowing therethrough along a circumference of the processing chamber), and also provides a means for entraining processing media in the flow of fluid.

Expelling a flow of fluid through an outlet in the processing chamber prevents a build-up of pressure in the processing chamber. Expelling fluid may also create a vacuum or low pressure within the processing chamber, which encourages processing media and/or fluid to flow into the processing chamber from the inlet arrangement.

Expelling a flow of fluid through an outlet in the centre of the processing chamber (in particular, an outlet formed of an outlet tube extending downwards from an upper end of the processing chamber) has been found to facilitate a swirling flow of fluid and processing media within the processing chamber.

In exemplary embodiments, the step of providing processing media in the processing chamber comprises providing two or more types of processing media in the processing chamber, wherein the two or more types of processing media each comprise a different particle size and/or hardness and/or shape and/or other material property; optionally, wherein each type of processing media is selected for performing a specific predetermined function relative to the or each other type of processing media (e.g. a de-powdering function as opposed to a smoothing function or a roughening function).

Providing two or more different types of processing media facilitates effective removal of powder from AM parts. For example, impacting (i.e. "blasting") coarse processing media has been found to more effectively break apart a powder cake or dislodge large chunks of powder, while impacting with fine processing media has been found to more effectively remove powder from small cracks or crevices. In addition, a combination of different types of processing media has been found to allow powder to be effectively removed from AM parts or powder cakes, and surfaces of the AM parts to be smoothed or roughened as desired in a single processing cycle (e.g. by using a glass-based media for bulk powder removal and metal or ceramic-based media for alteration of surface properties).

In exemplary embodiments, the processing media comprises metal processing media such as metal beads.

Metal processing media has been found to be particularly effective for removing powder from AM parts because there is more kinetic energy when the metal processing media impacts the AM part than there is with lighter processing media (e.g. glass beads).

Furthermore, metal processing media can be more easily separated/isolated from removed powder (e.g. via use of magnets) than non-metallic processing media.

In exemplary embodiments, the step of impacting the one or more AM parts and/or powder cake with the processing media is carried out while the one or more AM parts and/or powder cake are still warm (i.e. above room temperature) from an AM build operation.

Carrying out the impacting step before the part(s)/powder cake(s) have cooled has been to facilitate better powder removal than when carried out after cooling and "gumming up" of the powder.

According to a second aspect of the invention, a method of processing one or more additively manufactured (AM) parts and/or a powder cake containing one or more AM parts is provided, the method comprising: locating one or more AM parts and/or a powder cake containing one or more AM parts in a processing chamber; providing two or more types of processing media in the processing chamber; and impacting the one or more AM parts and/or powder cake with the processing media; wherein the two or more types of processing media each comprise a different particle size and/or hardness and/or shape and/or other material property; optionally, wherein each type of processing media is selected for performing a specific predetermined function relative to the or each other type of processing media (e.g. a de-powdering function as opposed to a smoothing function or a roughening function).

Processing media (i.e. particles of glass, metal, ceramic or other material) can be used for a number of processing operations for AM parts/powder cakes. For example processing media can be used to remove powder from AM parts/powder cakes (e.g. via use of a glass- based media) or to alter the surface properties of AM parts (e.g. via use of an abrasive media such as metal or ceramic-based media).

The use of two or more different types of processing media facilitates effective removal of powder from AM parts and/or surface modification of AM parts (e.g. smoothing). For example, using a coarse type of processing media has been found to more effectively break apart a powder cake or dislodge large chunks of powder from an AM part, whereas use of a fine type of processing media has been found to be more effective in removing powder from small cracks or crevices of an AM part. In addition, a combination of different types of processing media has been found to allow powder to be effectively removed from AM parts or powder cakes, and surfaces of the AM parts to be smoothed or roughened as desired in a single processing cycle (e.g. by using a glass-based media for bulk powder removal and metal or ceramic-based media for alteration of surface properties).

In exemplary embodiments, the method further comprises selecting one or more types of processing media for input to the processing chamber during a processing operation; optionally, further comprising selecting a ratio of two or more different types of processing media for input to the processing chamber during a processing operation.

Selecting one or more types of processing media and/or a ratio of two or more different types of processing media for input to the processing chamber during a processing operation (e.g. via a user input and/or control system operation), allows an optimal type of processing media or combination of different types to be used for a given processing operation.

In exemplary embodiments, selecting one or more types of processing media for input to the processing chamber during a processing operation comprises determining one or more appropriate types of processing media based on a type of part.

Determining one or more appropriate types of processing media based on a type of part (e.g. via a lookup table stored in a control system) allows the optimal type of processing media or combination of different types to be used. If automated (e.g. via a control system) this step also reduces the knowledge requirements of an operator (who may not know the optimal type(s) of processing media for a given part) and/or reduces human error (e.g. an operator may be less likely to select an incorrect part than an incorrect type of processing media). In exemplary embodiments, the method further comprises introducing the two or more types of processing media to the processing chamber during a processing operation via an inlet arrangement; optionally, wherein the inlet arrangement comprises two or more inlet pipes each connected to a respective processing media tank; optionally, wherein the two or more inlet pipes converge to a single inlet portion prior to entering the processing chamber.

Introducing the two or more types of processing media to the processing chamber via an inlet arrangement allows the volume and/or flow rate of the processing media to be controlled.

Having two or more inlet pipes each connected to a respective processing media tank facilitates supplying only one type of processing media, or a combination of different types of processing media at any given time instance (e.g. there is more flexibility than when processing media are mixed in a single tank).

The two or more inlet pipes converging to a single inlet portion prior to entering the processing chamber facilitates mixing of processing media, which has been found to improve processing performance. Having a single inlet portion also removes need for multiple inlets to the processing chamber, which reduces the impact on a flow of fluid in the processing chamber (e.g. a swirling flow path).

In exemplary embodiments, the method further comprises controlling the input of different types of processing media to the processing chamber during a processing operation; optionally, wherein controlling the input of different types of processing media to the processing chamber during a processing operation comprises altering a ratio of different types of processing media input to the processing chamber during different stages of a processing operation.

Controlling the input of different types of processing media to the processing chamber allows the volume and/or flow rate of the processing media to be controlled for optimal processing performance.

Altering a ratio of different types of processing media input to the processing chamber during different stages of a processing operation allows an optimal type of processing media or combination of different types to be used at each stage. For example, coarse particles have been found to be most suitable for breaking apart a powder cake in an initial "unpacking" stage, while fine particles have been found to be most suitable for removing powder from small cracks and crevices during a final "cleaning" stage.

In exemplary embodiments, the method further comprises performing a separation operation for separating processing media from powder amassed during or after the processing operation.

By isolating powder it can be re-used in a new additive manufacturing build operation. Similarly, by isolating processing media it can be re-used (e.g. stored in a tank for use in a subsequent processing operation, or recycled through the processing chamber in the same processing operation).

In exemplary embodiments, the processing media comprises metal processing media such as metal beads.

Metal processing media has been found to be particularly effective for removing powder from AM parts because there is more kinetic energy when the metal processing media impacts the AM part than there is with lighter processing media (e.g. glass beads).

Furthermore, metal processing media can be more easily separated/isolated from removed powder (e.g. via use of magnets) than non-metallic processing media.

In exemplary embodiments, the step of impacting the one or more AM parts and/or powder cake with the processing media is carried out while the one or more AM parts and/or powder cake are still warm (i.e. above room temperature) from an AM build operation.

Carrying out the impacting step before the part(s)/powder cake(s) have cooled has been to facilitate better powder removal than when carried out after cooling and "gumming up" of the powder.

According to a third aspect of the invention, a method of processing one or more additively manufactured (AM) parts and/or a powder cake containing one or more AM parts is provided, the method comprising: locating one or more AM parts and/or a powder cake containing one or more AM parts in a processing chamber; providing processing media in the processing chamber; and performing a processing operation wherein the one or more AM parts and/or powder cake are impacted by the processing media; and performing a separation operation for separating processing media from powder amassed during or after the processing operation.

Processing media (i.e. particles of glass, metal, ceramic or other material) can be used for a number of processing operations for AM parts/powder cakes. For example processing media can be used to remove powder from AM parts/powder cakes (e.g. via use of a glass- based media) or to alter the surface properties of AM parts (e.g. via use of an abrasive media such as metal or ceramic-based media).

By separating/isolating powder it can be re-used in a new additive manufacturing build operation. Similarly, by separating/isolating processing media it can be re-used (e.g. stored in a tank for use in a subsequent processing operation, or recycled through the processing chamber in the same processing operation).

In exemplary embodiments, the method further comprises the step of re-using the separated powder in an additive manufacturing build operation.

By re-using the separated powder in another additive manufacturing build operation, the separated/isolated powder is not wasted, which improves the environmental efficiency of the additive manufacturing process, and reduces costs associated with raw powder materials.

In exemplary embodiments, the step of performing a separation operation comprises transferring a mixture of processing media and removed powder from the processing chamber to a separating arrangement.

Transferring processing media and removed powder to a separating arrangement (e.g. an apparatus separate to the processing chamber) simplifies the construction of the processing chamber (e.g. the processing chamber can be optimised for powder removal, rather than also having to be configured for performing a separation operation).

In exemplary embodiments, the separating arrangement comprises two or more separating screens and/or sieves and/or filters; optionally, wherein the step of performing a separation operation further comprises vibrating and/or shaking and/or providing ultrasonic energy to at least a portion of the separating arrangement.

The use of two or more separating screens/sieves/filters allows processing media and/or removed powder to be effectively isolated. Vibrating or shaking at least a portion of the separating arrangement (e.g. the screens/sieves/filters, or the whole mechanism), encourages a movement of processing media and powder through the separating arrangement.

In exemplary embodiments, the method further comprises storing separated processing media for use in another processing operation, and/or recycling separated processing media through the processing chamber and impacting the one or more AM parts and/or powder cake with the recycled processing media, and/or storing separated powder for use in another additive manufacturing build operation.

By storing the separated/isolated processing media, it can be re-used in future processing operations. By recycling the separated/isolated processing media through the processing chamber and impacting the AM parts/powder cake with the recycled processing media, the apparatus acts as a closed system, which reduces the amount of processing media required for a processing operation. Recycling processing media reduces the size of or mitigates the need for processing media storage tanks. By storing separated/isolated powder for use in another additive manufacturing build operation, the separated/isolated powder is not wasted, which improves the environmental efficiency of the additive manufacturing process, and reduces costs associated with raw powder materials.

In exemplary embodiments, the step of providing processing media in the processing chamber comprises providing two or more types of processing media in the processing chamber, and wherein the step of performing a separation operation comprises isolating the two or more types of processing media from each other.

Isolating the two or more different types of processing media is particularly useful when the ratio of different types of processing media is varied for different processing operations or during different stages of a processing operation, since it allows the isolated media to be stored or re-cycled directly into the processing chamber in an appropriate ratio.

In exemplary embodiments, the step of impacting the one or more AM parts and/or powder cake with the processing media comprises entraining the processing media in a flow of fluid (e.g. air) within the processing chamber and wherein the step of performing a separation operation further comprises filtering a flow of fluid (e.g. air) expelled from the processing chamber; optionally, further comprising recycling filtered fluid through the processing chamber. Filtering a flow of fluid expelled from the processing chamber removes particles (e.g. powder) prior to re-cycling or emitting to the atmosphere. Such a filter is particularly useful when emitting to the atmosphere (which is likely to be a factory where people are working), since it prevents inhalation of small particles by people in proximity to the processing chamber.

In exemplary embodiments, the processing media comprises a de-powdering media (e.g. a glass-based media), wherein the method comprises impacting the one or more AM parts and/or powder cake with the de-powdering media to remove powder from the one or more AM parts and/or powder cake.

In exemplary embodiments, the processing media comprises an abrasive media (e.g. metal-based or ceramic-based media), wherein the method comprises impacting the one or more AM parts with the abrasive media to alter one or more surface properties of the one or more AM parts.

In exemplary embodiments, the processing media comprises metal processing media such as metal beads.

Metal processing media has been found to be particularly effective for removing powder from AM parts because there is more kinetic energy when the metal processing media impacts the AM part than there is with lighter processing media (e.g. glass beads).

Furthermore, metal processing media can be more easily separated/isolated from removed powder (e.g. via use of magnets) than non-metallic processing media.

In exemplary embodiments, the step of impacting the one or more AM parts and/or powder cake with the processing media is carried out while the one or more AM parts and/or powder cake are still warm (i.e. above room temperature) from an AM build operation.

Carrying out the impacting step before the part(s)/powder cake(s) have cooled has been to facilitate better powder removal than when carried out after cooling and "gumming up" of the powder.

According to a fourth aspect of the invention, an apparatus for processing one or more additively manufactured (AM) parts and/or a powder cake containing one or more AM parts is provided, the apparatus comprising a processing chamber having a rotating device (e.g. in the form of a rotating drum), wherein the rotating device is configured to receive one or more AM parts and/or a powder cake containing one or more AM parts; and wherein the rotating device is configured to move one or more AM parts and/or a powder cake located within the rotating device, for agitation of powder and/or removal of powder and/or exposing different faces of said one or more AM parts and/or powder cake to a flow of fluid and/or processing media within the processing chamber.

Such a rotating device (e.g. drum) has been found to be suitable for automated agitation and removal of powder from AM parts or powder cakes located therein (e.g. via shaking and/or spinning such AM parts or powder cakes). Furthermore, when such a rotating device is used in a processing chamber configured to induce a flow of fluid and/or processing media, the rotating device will move the AM parts or powder cakes to expose different faces of the AM parts or powder cakes to the flow of fluid and/or processing media. Exposing different faces of parts/powder cakes to a flow of fluid and/or processing media has been found to facilitate an automated removal of powder from the AM parts and/or powder cake and/or an automated alteration of surface properties of the one or more AM parts.

In exemplary embodiments, the rotating device is perforated to permit powder and/or fluid and/or processing media to be input to or output from the rotating device.

The rotating device being perforated prevents a build-up of removed powder and/or processing media within the rotating device, and allows a flow of fluid and/or processing media to be used to impact the one or more AM parts and/or powder cake for removal of powder or alteration of surface properties.

In exemplary embodiments, the processing apparatus is configured so that the rotating device is removable from the processing chamber.

The rotating device being removable allows processing of larger parts or powder cakes (e.g. parts or powder cakes which would not fit in the rotating device) within the processing chamber, and also facilitates better processing efficiency where rotation of parts is not necessary (since removal of the drum would lead to less impact on a flow of fluid and/or processing media within the processing chamber).

In exemplary embodiments, the rotating device comprises a device opening for input of AM parts or powder cakes to the rotating device or removal of de-powdered or surface- altered parts from the rotating device; optionally, wherein the device opening is defined by an open end of the rotating device.

Such a device opening provides a means for parts or powder cakes to be input or removed from the rotating device.

In exemplary embodiments, the processing apparatus further comprises a mechanism for inducing a flow of processing media within the processing chamber for impacting one or more AM parts and/or a powder cake with the processing media in use.

Processing media (i.e. particles of glass, metal, ceramic or other material) can be used for a number of processing operations for AM parts/powder cakes. For example processing media can be used to remove powder from AM parts/powder cakes (e.g. via use of a metal or glass-based media) or to alter the surface properties of AM parts (e.g. via use of an abrasive media such as metal or ceramic-based media). Therefore, an apparatus with such a mechanism for inducing a flow of processing media within the processing chamber has been found to be effective for removal of powder from AM parts and/or powder cakes and/or alteration of surface properties of AM parts.

According to a fifth aspect of the invention, an apparatus for processing one or more additively manufactured (AM) parts and/or a powder cake containing one or more AM parts is provided, the apparatus comprising: a processing chamber for receiving one or more AM parts and/or a powder cake containing one or more AM parts; and a mechanism for inducing a flow of processing media within the processing chamber for impacting one or more AM parts and/or a powder cake with the processing media in use.

Processing media (i.e. particles of glass, metal, ceramic or other material) can be used for a number of processing operations for AM parts/powder cakes. For example processing media can be used to remove powder from AM parts/powder cakes (e.g. via use of a metal or glass-based media) or to alter the surface properties of AM parts (e.g. via use of an abrasive media such as metal or ceramic-based media). Therefore, an apparatus with such a mechanism for inducing a flow of processing media within the processing chamber has been found to be effective for removal of powder from AM parts and/or powder cakes and/or alteration of surface properties of AM parts. In exemplary embodiments, the processing apparatus is configured to create a swirling flow path for said processing media within the processing chamber for impacting the one or more AM parts and/or powder cake with the processing media in use.

The use of a swirling (i.e. cyclonic or vortex-like) flow path for said processing media within the processing chamber has been found to provide multiple processing benefits for the processing of AM parts or powder cakes containing one or more AM parts. The swirling processing media is able to impact (e.g. "blast") any AM parts or powder cakes located within the processing chamber from multiple directions, which reduces or mitigates the need to flip or rotate AM parts or powder cakes within the processing chamber, thereby leading to more efficient automated processing of the AM parts or powder cakes. The swirling flow path can be used to provide fast and efficient removal of excess powder from powder cakes (in order to reveal the AM part(s) within), as well as effective removal of excess powder from different faces of an AM part. A swirling (i.e. cyclonic or vortex-like) processing media flow path may also be used to effectively alter the surface properties of an AM part (e.g. by smoothing or roughening the surface).

In exemplary embodiments, the processing chamber is defined by one or more chamber walls and at least a portion of the one or more chamber walls has a substantially circular cross-section; optionally, wherein the one or more chamber walls comprise a cylindrical portion and/or a conical portion and/or a frustoconical portion and/or a polygonal portion which approximates a cylindrical portion and/or a polygonal portion which approximates a conical or frustoconical portion; optionally, wherein the processing chamber comprises a cylindrical portion and a conical or frustoconical portion below the cylindrical portion.

Having at least a portion with a substantially circular cross-section facilitates the formation of a swirling flow path in said portion (e.g. along a circumference of said portion).

Having a cylindrical portion and/or conical portion and/or frustoconical portion (or polygonal approximations thereof) has been found to facilitate the formation of a swirling processing media flow path (since such shapes have substantially circular cross-sections or approximations of circular cross-sections).

It has been found that a processing chamber with a cylindrical portion and a conical or frustoconical portion below the cylindrical portion is particularly suitable for generating a swirling processing media flow path. In exemplary embodiments, the processing apparatus further comprises an inlet arrangement for introducing processing media to the processing chamber, wherein the processing apparatus is configured to direct processing media from the inlet arrangement along an internal circumference of said portion of the one or more chamber walls having a substantially circular cross-section to induce the swirling processing media flow path.

Directing processing media along a circumference of a cylindrical or conical orfrustoconical portion of a processing chamber has been found to be an effective method for forming a swirling flow path for said processing media.

In exemplary embodiments, the processing chamber defines a longitudinal axis, and wherein the inlet arrangement is offset from the longitudinal axis; optionally, wherein the inlet arrangement defines an inlet axis along which processing media is introduced to the processing chamber, and wherein the inlet axis is approximately tangential to the circumference of the processing chamber.

Offsetting the inlet arrangement from the longitudinal axis of the processing chamber provides a simple means of directing processing media along the circumference of the processing chamber and inducing a swirling processing media flow path.

Having an inlet axis approximately tangential to the circumference of the processing chamber provides a simple means of directing processing media along the circumference of the processing chamber and inducing a swirling processing media flow path.

In exemplary embodiments, the inlet arrangement comprises an angled ramp (e.g. downwardly angled) for introducing processing media to the processing chamber.

Having an angled ramp (e.g. a downwardly angled ramp) has been found to assist a flow of processing media into the processing chamber (i.e. via gravity), which increases the kinetic energy of the processing media entering the processing chamber, and helps to facilitate the swirling flow path for said processing media.

In exemplary embodiments, the processing apparatus further comprises one or more baffles for inducing the swirling processing media flow path; optionally, wherein the one or more baffles are arranged to direct processing media along a circumference of the processing chamber to induce the swirling processing media flow path; optionally, wherein the one or more baffles comprise an angled ramp along the circumference of the processing chamber. Having one or more baffles provides an alternative, or additional means for inducing a swirling processing media flow path within the processing chamber.

In exemplary embodiments, the processing apparatus comprises an inlet arrangement for introducing processing media to the processing chamber, and wherein the processing apparatus is configured to introduce two or more types of processing media to the processing chamber via the inlet arrangement.

The use of two or more different types of processing media facilitates effective removal of powder from AM parts and/or surface modification of AM parts (e.g. smoothing). For example, using a coarse type of processing media has been found to more effectively break apart a powder cake or dislodge large chunks of powder from an AM part, whereas use of a fine type of processing media has been found to be more effective in removing powder from small cracks or crevices of an AM part. In addition, a combination of different types of processing media has been found to allow powder to be effectively removed from AM parts or powder cakes, and surfaces of the AM parts to be smoothed or roughened as desired in a single processing cycle (e.g. by using a metal or glass-based media for bulk powder removal and metal or ceramic-based media for alteration of surface properties). Furthermore, introducing the two or more types of processing media to the processing chamber via an inlet arrangement allows the volume and/or flow rate of the processing media to be controlled.

In exemplary embodiments, the inlet arrangement comprises two or more inlet pipes each connected to a respective processing media tank; optionally, wherein the two or more inlet pipes converge to a single inlet portion prior to entering the processing chamber.

Having two or more inlet pipes each connected to a respective processing media tank facilitates supplying only one type of processing media, or a combination of different types of processing media at any given time instance (e.g. there is more flexibility than when processing media are mixed in a single tank).

The two or more inlet pipes converging to a single inlet portion prior to entering the processing chamber facilitates mixing of processing media, which improves processing performance. Having a single inlet portion also removes need for multiple inlets to the processing chamber, which reduces the impact on a flow of fluid in the processing chamber (e.g. a swirling flow path). In exemplary embodiments, the processing apparatus further comprises a control system configured to control the input of different types of processing media to the processing chamber; optionally, wherein the control system is configured to select one or more types of processing media for input to the processing chamber; optionally, wherein the control system is configured to alter a ratio of different types of processing media input to the processing chamber; optionally, wherein the control system is configured to alter a ratio of different types of processing media input to the processing chamber during different stages of a processing operation; optionally, wherein the control system is configured to determine one or more appropriate types of processing media based on a type of part; optionally, wherein the control system comprises one or more user inputs; optionally, wherein the one or more user inputs comprise: type of processing media and/or ratio of types of processing media and/or fluid flow rate and/or processing cycle duration and/or type of part.

Controlling the input of different types of processing media to the processing chamber allows the volume and/or flow rate of the processing media to be controlled for optimal processing performance.

Altering a ratio of different types of processing media input to the processing chamber allows an optimal type of processing media or combination of different types to be used for a given processing operation.

Altering a ratio of different types of processing media input to the processing chamber during different stages of a processing operation allows an optimal type of processing media or combination of different types to be used at each stage. For example, coarse particles have been found to be most suitable for breaking apart a powder cake in an initial "unpacking" stage, while fine particles have been found to be most suitable for removing powder from small cracks and crevices during a final "cleaning" stage.

Determining one or more appropriate types of processing media based on a type of part (e.g. via a lookup table stored in a control system) allows the optimal type of processing media or combination of different types to be used. If automated (e.g. via a control system) this step also reduces the knowledge requirements of an operator (who may not know the optimal processing media type(s) for a given part) and/or reduces human error (e.g. an operator may be less likely to select an incorrect part than an incorrect type of processing media). The control system having one or more user inputs allows an operator to select a desired set of parameters for a processing operation.

In exemplary embodiments, the processing apparatus further comprises an outlet arrangement for transfer of removed powder and/or processing media from the processing chamber.

Providing such an outlet arrangement inhibits a build-up of removed powder and/or processing media within the processing chamber which could reduce effectiveness of processing (e.g. via covering parts).

In exemplary embodiments, the processing chamber comprises a perforated member provided between the inlet arrangement and the outlet arrangement, wherein the perforated member is provided for supporting one or more AM parts and/or a powder cake thereon and for permitting removed powder and processing media to pass through to the outlet arrangement.

Such a perforated member provides a simple means for supporting parts or powder cakes in the processing chamber without inhibiting a flow of media and/or fluid and/or removed powder to the outlet arrangement.

In exemplary embodiments, the processing chamber comprises a rack or hook for supporting one or more AM parts and/or a powder cake.

In exemplary embodiments, the perforated member is rotatable (e.g. rotatable by 360 degrees) and/or tiltable (e.g. tiltable by 45 degrees).

The perforated member being rotatable and/or tiltable allows parts located thereon to be moved so that a flow of processing media impacts the parts from different angles.

In exemplary embodiments, the processing apparatus further comprises a separating arrangement configured to separate processing media from powder amassed during or after a processing operation; optionally, wherein the separating arrangement is coupled to the outlet arrangement.

By separating/isolating powder it can be re-used in a new additive manufacturing build operation. Similarly, by separating/isolating processing media it can be re-used (e.g. stored in a tank for use in a subsequent processing operation, or recycled through the processing chamber in the same processing operation).

In exemplary embodiments, the separating arrangement comprises one or more separating screens and/or sieves and/or filters; optionally, wherein the separating arrangement comprises two or more separating screens and/or sieves and/or filters; optionally, wherein the separating arrangement comprises three or more separating screens and/or sieves and/or filters; optionally, wherein the separating arrangement comprises a vibrating and/or shaking and/or ultrasonic adapted separating mechanism; optionally, wherein separating arrangement further comprises a filter for filtering fluid (e.g. air) expelled from the processing chamber; optionally, wherein the processing apparatus is configured to re-cycle filtered fluid from the separating arrangement to the processing chamber.

The use of one or more separating screens/sieves/filters allows processing media and/or removed powder to be effectively isolated.

The use of two or more separating screens/sieves/filters allows two or more types of processing media and/or removed powder to be effectively isolated.

The use of two or more separating screens/sieves/filters allows two or more types of processing media and removed powder to be effectively isolated.

Having a vibrating and/or shaking and/or ultrasonic adapted separating mechanism encourages a movement of processing media and powder through the separating arrangement.

Filtering a flow of fluid expelled from the processing chamber removes particles (e.g. powder) prior to re-cycling or emitting to the atmosphere. Such filtering is particularly useful when emitting to the atmosphere (which is likely to be a factory where people are working), since it prevents inhalation of small particles by people in proximity to the processing chamber.

In exemplary embodiments, the separating arrangement is configured to transfer separated processing media to one or more processing media tanks, and/or wherein the processing apparatus is configured to re-cycle separated processing media from the separating arrangement through the processing chamber, and/or wherein the separating arrangement is configured to transfer separated powder to one or more powder tanks. By storing the separated/isolated processing media in one or more tanks, it can be re used in future processing operations. By recycling the separated/isolated processing media through the processing chamber and impacting the AM parts/powder cake with the recycled processing media, the apparatus acts as a closed system, which reduces the amount of processing media required for a processing operation. Recycling processing media also reduces the size of or mitigates the need for processing media storage tanks. By storing separated/isolated powder in one or more tanks it can be used in another additive manufacturing build operation (i.e. the separated/isolated powder is not wasted, which improves the environmental efficiency of the additive manufacturing process, and reduces costs associated with raw powder materials).

In exemplary embodiments, the processing apparatus comprises an inlet arrangement for introducing processing media to the processing chamber.

Introducing processing media to the processing chamber via an inlet arrangement allows the volume and/or flow rate of the processing media to be controlled (e.g. as opposed to systems where all the processing media is provided in a tray or the like within the processing chamber.

In exemplary embodiments, the processing apparatus is configured to induce a flow of fluid (e.g. air) and/or processing media within the processing chamber for impacting one or more AM parts and/or a powder cake located within the processing chamber with said fluid and/or processing media; optionally, wherein the processing apparatus comprises a blower having a motor and an impeller driven by the motor for inducing a flow of fluid and/or processing media within the processing chamber; optionally, wherein the processing apparatus comprises one or more pumps for inducing a flow of fluid and/or processing media around the processing apparatus (e.g. within the processing chamber).

Providing a blower to induce a flow of fluid within the processing chamber increases the processing effectiveness. For example, in cases where processing media is provided in the processing chamber, such a flow of fluid provides a means for transferring kinetic energy to the processing media (i.e. via entraining in the flow of fluid) which increases the force at which the processing media impacts AM parts or powder cakes.

A motor-driven impeller provides a simple means for inducing a flow of fluid within a processing chamber. Pumps provide a flexible and controllable means for driving fluid (and any processing media entraining therein) around the processing apparatus.

In exemplary embodiments, the processing apparatus is configured to expel fluid (e.g. air) from the processing chamber; optionally, wherein the processing apparatus is configured to expel fluid (e.g. air) from the processing chamber to create a region of low pressure proximal the or an inlet arrangement for urging a flow of processing media through the inlet arrangement to the processing chamber; optionally, wherein the processing chamber comprises an outlet tube having a fixed end coupled to an end of the processing chamber and a free end within the processing chamber, and wherein the processing apparatus is configured to expel fluid (e.g. air) from the processing chamber via the outlet tube; optionally, wherein a longitudinal axis of the outlet tube is aligned with a longitudinal axis of the processing chamber.

Configuring the processing apparatus to remove fluid from the processing chamber prevents a build-up of fluid within the processing chamber (e.g. in the case where fluid is also being input to the processing chamber via one or more pumps).

Creating a region of low pressure proximal the inlet arrangement has been found to urge processing media into the processing chamber, which increases its kinetic energy for impacting AM parts or powder cakes in the processing chamber.

Having an outlet tube with a free end within the processing chamber means that fluid is removed from the middle of the processing chamber, rather than at one end. Removing fluid from the middle of the processing chamber has been found to facilitate formation of a low pressure region at the end of the processing chamber (i.e. the end to which the fixed end of the outlet tube is attached). When the inlet arrangement is located proximal said end of the processing chamber, said low pressure region has been found tol urge processing media to flow into the processing chamber.

Such an outlet tube arrangement has been found to facilitate a swirling flow of fluid within the processing chamber, which improves processing efficiency either on its own, or in combination with processing media entrained within the swirling flow.

In exemplary embodiments, the processing chamber comprises a chamber opening for input of AM parts and/or powder cakes to the processing chamber or removal of AM parts from the processing chamber; optionally, wherein the chamber opening is provided on a side of the processing chamber; optionally, wherein the processing chamber further comprises a door, lid or the like for sealing the chamber opening during a processing operation.

Such a chamber opening allows parts to be easily input or removed from the processing chamber.

In exemplary embodiments, the processing apparatus further comprises an automated mechanism for inserting and/or removing AM parts and/or powder cakes from the processing chamber (e.g. via the chamber opening).

Having an automated mechanism for inserting and/or removing AM parts and/or powder cakes reduces the requirements for manual operation of the system, which results in a more efficient processing operation.

In exemplary embodiments, the automated mechanism comprises a robotic arm for movement of one or more AM parts and/or powder cakes.

In exemplary embodiments, the automated mechanism comprises a vision system for determining the location of one or more AM parts and/or powder cakes.

In exemplary embodiments, the processing apparatus comprises a control system configured to operate the processing apparatus; optionally, wherein the control system is operated via one or more user inputs; optionally, wherein the one or more user inputs comprise: type of part and/or type of processing media and/or ratio of different types of processing media and/or fluid flow rate and/or processing cycle duration; optionally, wherein the control system is configured to automatically determine a type of processing media and/or ratio of different types of processing media and/or fluid flow rate and/or processing cycle duration based on a type of part.

The control system having one or more user inputs allows an operator to select a desired set of parameters for a processing operation.

Determining one or more appropriate types of processing media based on a type of part (e.g. via a lookup table stored in a control system) allows the optimal type of processing media or combination of different types to be used. If automated (e.g. via a control system) this step also reduces the knowledge requirements of an operator (who may not know the optimal type(s) of processing media for a given part) and/or reduces human error (e.g. an operator may be less likely to select an incorrect part than an incorrect type of processing media).

In exemplary embodiments, the processing apparatus further comprises a compressed fluid source (e.g. compressed air source) coupled to one or more nozzles configured to impact the one or more AM parts and/or powder cake with high pressure fluid (e.g. compressed air) from the compressed fluid source.

Providing high pressure fluid via the nozzle(s) is useful for breaking apart a powder cake, moving parts to expose different faces to a flow of fluid/processing media, and/or for removing powder from or altering surface properties within cracks or crevices in AM parts.

In exemplary embodiments, one or more of said nozzles comprises an air flow amplifier.

Having an air flow amplifier increases the volumetric flow rate and/or flow velocity through one or more of said nozzles, which has been found to increase processing performance.

In exemplary embodiments, one or more of said nozzles is moveable (e.g. via a robotic arm).

One or more nozzles being moveable (e.g. via a robotic arm) allows high pressure fluid to be directed to regions of AM parts/powder cakes which are difficult to clean/de-powder (e.g. cracks/crevices which may be sheltered from a flow of processing media in the processing chamber).

In exemplary embodiments, the processing apparatus system further comprises a sensor configured to detect a de-powdering state of the one or more AM parts (e.g. a load cell to detect a weight of the one or more AM parts and/or powder cake and/or powder within the processing chamber).

Having a sensor configured to detect a de-powdering state of the one or more AM parts allows the system to be automated, which reduces the need for manual input to the de- powdering process (e.g. determining an appropriate cycle time, checking whether parts are de-powdered and re-running a de-powdering operation if checked parts are not fully de-powdered).

In exemplary embodiments, the processing apparatus is configured to prevent generation of static electricity in the processing chamber and/or cancel static electricity generated within the processing chamber; optionally, wherein the processing apparatus comprises one or more de-ionising devices.

Preventing generation of static electricity and/or cancelling static energy reduces the likelihood of damage to the processing apparatus and/or AM parts. Preventing generation of static electricity and/or cancelling static energy also prevents AM parts from being charged in ways which would be detrimental to further processing operations, such as coating operations.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a cross section view of an apparatus for processing AM parts and/or powder cakes, according to an embodiment;

Figure 2 is a side view of the apparatus of Figure 1;

Figure 3 is an alternative cross section view of the apparatus of Figures 1 and 2;

Figure 4 is a perspective view of a separating arrangement of the apparatus of Figures 1 to 3;

Figure 5 is a cross section view of the separating arrangement of Figure 4;

Figure 6 is an enlarged perspective cross section view of a processing chamber of the apparatus of Figures 1 to 3, including a rotating device;

Figure 7 is an enlarged side cross section view of the processing chamber and rotating device of Figure 6;

Figure 8 is a perspective view of an apparatus for processing AM parts and/or powder cakes according to an embodiment, the apparatus including a cabinet housing the apparatus of Figures 1 to 3; and

Figure 9 is a rear view of the apparatus of Figure 8 showing the sifting mechanism and a manual blasting cabinet.

DETAILED DESCRIPTION Referring firstly to Figures 1 to 3, an apparatus for processing one or more additively manufactured (AM) parts and/or a powder cake containing one or more AM parts is indicated at 10. The processing apparatus 10 includes a processing chamber 12 for receiving one or more AM parts and/or a powder cake containing one or more AM parts. As will be described in more detail below, the processing apparatus 10 also includes a mechanism for inducing a flow of processing media within the processing chamber 12, for impacting one or more AM parts and/or a powder cake with the processing media in use.

Processing media (i.e. particles of glass, metal, ceramic or other material) can be used for a number of processing operations for AM parts/powder cakes using the processing apparatus 10. In exemplary embodiments, the processing media is of a kind selected for removing powder from AM parts/powder cakes located within the processing chamber 12, hereinafter a de-powdering media, e.g. a glass-based media. In exemplary embodiments, the processing media is of a kind selected for altering the surface properties of AM parts located within the processing chamber 12 (i.e. beyond mere de-powdering of the surface), hereinafter an abrasive media, e.g. metal-based or ceramic-based media.

In the illustrated embodiment, the processing apparatus 10 is configured to create a swirling flow path for said processing media within the processing chamber 12, for impacting the one or more AM parts and/or powder cake with the processing media in use. The use of a swirling (i.e. cyclonic or vortex-like) flow path for said processing media within the processing chamber 12 has been found to provide multiple processing benefits for the processing of AM parts or powder cakes containing one or more AM parts. The swirling processing media is able to impact (e.g. "blast") any AM parts or powder cakes located within the processing chamber from multiple directions, which reduces or mitigates the need to flip or rotate AM parts or powder cakes within the processing chamber, thereby leading to more efficient automated processing of the AM parts or powder cakes. The swirling flow path has been found to provide fast and efficient removal of excess powder from powder cakes (in order to reveal the AM part(s) within), as well as effective removal of excess powder from different faces of an AM part. A swirling (i.e. cyclonic or vortex like) processing media flow path has also been found to effectively alter the surface properties of an AM part beyond mere de-powdering of the surface (e.g. by smoothing or roughening the surface).

As will be described in more detail below, the processing chamber 12 is defined by one or more chamber walls 13. In exemplary embodiments, at least a portion of the one or more chamber walls 13 has a substantially circular cross-section, as will be described in more detail below.

In the illustrated embodiment, the chamber walls 13 define a cylindrical portion 14 and a frustoconical portion 16 below the cylindrical portion 14. In the illustrated embodiment, the frustoconical portion 16 defines a relatively long frustum (i.e. almost a full cone). However, in alternative embodiments, the frustoconical portion 16 defines a relatively shorter frustum. It has been found that a processing chamber 12 with chamber walls 13 defining a cylindrical portion 14 and frustoconical portion 16 below the cylindrical portion 14 is particularly suitable for generating a swirling processing media flow path in the processing chamber 12. However, in alternative embodiments, the processing chamber 12 has one or more chamber walls 13 defining any other combination of a cylindrical portion 14 and/or a conical portion and/or a frustoconical portion 16 and/or a spherical portion and/or a part-spherical portion, which will still be suitable for generating a swirling media flow path (since such shapes have substantially circular cross-sections). In alternative embodiments, the processing chamber 12 has one or more chamber walls 13 defining any other configuration suitable for generating a swirling processing media flow path. For example, the chamber may have chamber walls defining one or more polygonal portions approximating a cylindrical portion and/or a conical portion and/or a frustoconical portion (e.g. polygonal portions of 5 or more sides, such as those of hexagonal cross sections). Alternatively, the swirling media flow path may be induced via formations such as baffles within the processing chamber 12 instead of, or in addition to, the shape of the chamber wall(s) 13 of the processing chamber 12.

In the illustrated embodiment, the processing apparatus 10 has an inlet arrangement 18 for introducing processing media to the processing chamber 12. The processing apparatus 10 is configured to direct processing media from the inlet arrangement 18 along an internal circumference 20 of the chamber walls 13 of the processing chamber 12 (i.e. the cylindrical portion 14) to induce the swirling processing media flow path. The inlet arrangement 18 allows processing media to be input to the processing chamber 12 during a processing operation. However, in alternative embodiments, the processing chamber is pre-charged with the processing media, so that processing media is provided within the processing chamber 12 without an inlet arrangement 18 (e.g. processing media is provided in a tray or other container within the processing chamber 12).

In the illustrated embodiment, the processing chamber 12 defines a longitudinal axis, and the inlet arrangement 18 is offset from the longitudinal axis (e.g. as best shown in Figure 2). It has been found that offsetting the inlet arrangement 18 provides a simple means of directing processing media along the circumference 20 of the processing chamber and inducing a swirling processing media flow path. In particular, the inlet arrangement 18 of the illustrated embodiment defines an inlet axis along which processing media is introduced to the processing chamber 12, and the inlet axis is approximately tangential to the circumference 20 of the processing chamber 12. Such a tangential inlet axis has been found to effectively inducing a swirling processing media flow path within the processing chamber 12.

In alternative embodiments, the inlet axis of the inlet arrangement 18 is aligned with the longitudinal axis of the processing chamber 12 or the inlet axis of the inlet arrangement 18 is provided between the longitudinal axis of the processing chamber 12 and an axis which is tangential to the circumference 20 of the processing chamber 12. In such embodiments, one or more baffles or other devices may be provided for directing processing media along the circumference 20 of the processing chamber 12, or for inducing a swirling processing media flow path via another mechanism.

In the illustrated embodiment, the inlet arrangement 18 includes a downwardly angled ramp 22 for introducing processing media to the processing chamber (as best shown in Figure 3). Such an angled ramp 22 has been found to assist a flow of processing media into the processing chamber 12 (i.e. via gravity) and to increase the kinetic energy of the processing media entering the processing chamber 12, which helps to facilitate the swirling flow path for said processing media.

In exemplary embodiments, the processing apparatus 10 includes one or more baffles or other devices (not shown) for inducing the swirling processing media flow path. For example, an angled ramp along the circumference of the processing chamber (e.g. a helical ramp). Such an angled/helical ramp may complement or replace the mechanisms for inducing a swirling media flow path shown in the illustrated embodiment. In exemplary embodiments, the processing apparatus 10 also includes one or more baffles or other devices (not shown) for directing processing media towards a region of the processing chamber 12 intended for location of AM parts or powder cakes.

In the illustrated embodiment, the inlet arrangement 18 is configured to introduce two different types of processing media to the processing chamber 12 via the inlet arrangement 18, as will be described in more detail below. In alternative embodiments, the inlet arrangement 18 is configured to introduce more than two different types of processing media to the processing chamber 12. The use of two or more different types of processing media facilitates effective removal of powder from AM parts and/or surface modification of AM parts (e.g. smoothing). For example, using a coarse type of processing media has been found to more effectively break apart a powder cake or dislodge large chunks of powder from an AM part, whereas use of a fine type of processing media has been found to be more effective in removing powder from small cracks or crevices of an AM part. In addition, a combination of different types of processing media has been found to allow powder to be effectively removed from AM parts or powder cakes, and surfaces of the AM parts to be smoothed or roughened as desired in a single processing cycle (e.g. by using a metal or glass-based media for bulk powder removal and metal or ceramic- based media for alteration of surface properties).

In the illustrated embodiment, the inlet arrangement 18 has two inlet pipes 24 each connected to a respective processing media tank 26 (e.g. as best shown in Figure 2). Having two inlet pipes 24 each connected to a respective processing media tank 26 facilitates supplying only one type of processing media, or a combination of different types of processing media at any given time instance (e.g. there is more flexibility than when processing media are mixed in a single tank). However, in alternative embodiments, two or more types of processing media are mixed within a single processing media tank 26, which requires only a single inlet pipe 24 for input of the two or more types of processing media to the processing chamber 12. In alternative embodiments, more or less than two inlet pipes 24 and two processing media tanks 26 are provided.

In the illustrated embodiment, the two inlet pipes 24 converge to a single inlet portion 30 prior to entering the processing chamber 12. Such a single inlet portion 30 facilitates mixing of processing media, which improves processing performance, removes need for multiple inlets to the processing chamber 12, and reduces the impact on a flow of fluid in the processing chamber 12 (e.g. a swirling flow path).

A pump 28 is provided in each inlet pipe 24 to propel processing media from the respective processing media tank 26 to the processing chamber 12 (e.g. via the single inlet portion 30 and angled ramp 22). The processing media tanks 26 may be vented so that the pumps 28 suck air into the processing media tanks 26 to entrain processing media from the processing media tanks 26 for transfer along the inlet pipes 24. However, any suitable mechanism for propelling processing media via the pumps 28 may be used.

In alternative embodiments, the processing media tank(s) 26 are provided above the inlet arrangement 18, so that a flow of processing media flows along the inlet pipe(s) 24 and into the processing chamber 12 via gravity alone, or via a combination of gravity and pump 28 action. In such embodiments, one or more valves may be provided (e.g. between the processing media tank(s) 26 and the inlet pipe(s) 24) for controlling the flow of processing media along the inlet pipe(s) 24.

The processing apparatus 10 includes a control system 76 configured to control the input of different types of processing media to the processing chamber 12. Controlling the input of different types of processing media allows the volume and/or flow rate of the processing media to be controlled for optimal processing performance.

In exemplary embodiments, the control system 76 is configured to select one or more types of processing media for input to the processing chamber 12.

In exemplary embodiments, the control system 76 is configured to alter a ratio of different types of processing media input to the processing chamber 12. Altering this ratio allows an optimal type of processing media or combination of different types to be used for a given processing operation. In exemplary embodiments, the control system 76 is configured to alter a ratio of different types of processing media input to the processing chamber 12 during different stages of a processing operation. Altering this ratio during different stages allows an optimal type of processing media or combination of different types to be used at each stage. For example, coarse particles have been found to be most suitable for breaking apart a powder cake in an initial "unpacking" stage, while fine particles have been found to be most suitable for removing powder from small cracks and crevices during a final "cleaning" stage. Another example includes using de-powdering media (metal or glass-based media) for a de-powdering stage and abrasive media (e.g. metal-based or ceramic-based media) for a surface property alteration stage (e.g. a smoothing or roughening stage).

In exemplary embodiments, the control system 76 is configured to determine one or more appropriate types of processing media based on a type of part (e.g. via a lookup table stored in a control system 76). Determining one or more appropriate types of processing media allows the optimal type of processing media or combination different types to be used, and reduces the knowledge requirements of an operator (who may not know the optimal type(s) of processing media for a given part) and/or reduces human error (e.g. an operator may be less likely to select an incorrect part than an incorrect type of processing media).

In exemplary embodiments, the control system 76 includes one or more user inputs 66 (e.g. as shown in Figure 8). In exemplary embodiments, the user inputs 66 include: type of processing media and/or ratio of types of processing media and/or fluid flow rate and/or processing cycle duration and/or type of part.

In the illustrated embodiment, the processing apparatus also includes an outlet arrangement 32 for transfer of removed powder and/or processing media from the processing chamber 12. Such an outlet arrangement 32 inhibits a build-up of removed powder and/or processing media within the processing chamber 12 which could reduce effectiveness of processing (e.g. via covering parts).

In the illustrated embodiment, the processing chamber 12 has a perforated member 34 provided between the inlet arrangement 18 and the outlet arrangement 32. The perforated member 34 is arranged for supporting one or more AM parts and/or a powder cake thereon and permitting removed powder and processing media to pass through to the outlet arrangement 32. In alternative embodiments, AM parts or powder cakes are supported within the processing chamber 12 via a different means (e.g. inside rotating device 58 with the perforated member 34 omitted). In alternative embodiments, the processing chamber 12 includes a rack or hook for supporting one or more AM parts (e.g. instead of, or in addition to the perforated member 34).

In exemplary embodiments, the perforated member 34 is rotatable (e.g. rotatable by 360 degrees) and/or tiltable (e.g. tiltable by 45 degrees). The perforated member 34 being rotatable and/or tiltable allows parts located thereon to be moved so that a flow of processing media impacts the parts from different angles.

The processing apparatus also includes a separating arrangement 36 configured to separate processing media from powder amassed during or after a processing operation. By separating/isolating powder it can be re-used in a new additive manufacturing build operation. Similarly, by separating/isolating processing media it can be re-used (e.g. stored in a tank for use in a subsequent processing operation, or recycled through the processing chamber 12 in the same processing operation).

As shown in Figures 2 and 3, the separating arrangement 36 is coupled to the outlet arrangement 32. Specifically, the outlet arrangement 32 includes an outlet pipe 33 connected to the separating arrangement 36. The outlet arrangement 32 also includes a pump 28 (i.e. for propelling a flow of fluid and/or processing media and/or powder along the outlet pipe 33 to the separating arrangement 36). Figures 4 and 5 show an embodiment in which, the separating arrangement 36 has a plurality of screens 38. The screens 38 each have openings which permit particles of narrower width to pass through the openings and prevent particles of wider width from passing through the openings. Each subsequent screen 38 in a flow path through the separating arrangement 36 has narrower openings than the previous screen 38. In this way, the largest particles are separated by the first screen 38, the second largest particles are separated by the second screen 38 and so on.

In the illustrated embodiment, the first screen 38 (i.e. the upper screen 38 in Figure 5) is arranged for separating unusually large debris (e.g. parts which have fallen through the perforated member 34 unintentionally) from processing media and powder. The second screen 38 (i.e. the middle screen 38 in Figure 5) is arranged for separating a first type of processing media (i.e. the coarsest type of processing media) from a second type of processing media and powder. The third screen 38 (i.e. the lower screen 38 in Figure 5) is arranged for separating the second type of processing media from powder.

In alternative embodiments, the separating arrangement 36 has a single screen 38 (e.g. a screen having openings wide enough to permit powder to pass through but narrow enough to prevent processing media to pass through, or vice versa).

The illustrated separating arrangement 36 includes a vibrating separating mechanism. Specifically, the separating arrangement 36 includes a vibration motor 40 and is mounted on resilient members 42 (e.g. springs) which permit movement of the separating arrangement 36 due to the action of the vibration motor 40. In alternative embodiments, the separating arrangement 36 is vibrated or shaken via other means (e.g. via an eccentric drive mechanism, or an ultrasonic energy source). Being a vibrating and/or shaking and/or ultrasonic adapted separating arrangement 36 encourages a movement of processing media and powder through the separating arrangement 36.

The separating arrangement 36 is configured to transfer separated processing media to respective processing media tanks 26 (e.g. via media return pipes 44). By storing the separated/isolated processing media in one or more tanks, it can be re-used in future processing operations. In exemplary embodiments, the processing apparatus 10 is configured to recycle separated processing media from the separating arrangement 36 through into the processing chamber 12 (e.g. directly, or via the processing media tanks 26). Recycling the separated/isolated processing media through the processing chamber 12 reduces the amount of processing media required for a processing operation. This recycling reduces the required size of or mitigates the need for processing media storage tanks 26.

In the illustrated embodiment, the separating arrangement 36 is also configured to transfer separated powder to one or more powder tanks 82. By storing separated/isolated powder in one or more tanks 82 it can be used in another additive manufacturing build operation (i.e. the separated/isolated powder is not wasted, which improves the environmental efficiency of the additive manufacturing process, and reduces costs associated with raw powder materials).

In the illustrated embodiment, a powder return pipe 48 is provided between the separating arrangement 36 and powder cabinet 46 having one or more powder tanks 82 for storing the separated powder. A pump 28 is provided to propel a flow of powder and fluid along the powder return pipe 48.

In exemplary embodiments, the powder cabinet 46 includes a filter 78 for filtering fluid (e.g. air) expelled from the processing chamber 12 (i.e. powder entrained fluid flowing along powder return pipe 48). This filter 78 allows particles (e.g. powder) to be separated prior to emitting the fluid to the atmosphere or re-cycling through the processing chamber 12. This filter 78 is particularly useful when emitting the fluid to the atmosphere (which is likely to be a factory where people are working), since it prevents inhalation of powder by people in proximity to the processing apparatus 12.

In exemplary embodiments, the processing apparatus 10 is configured to re-cycle filtered fluid from the powder cabinet 46 to the processing chamber 12 (e.g. in closed-loop embodiments where an inert gas is used in the processing chamber, rather than air which can be input from the atmosphere).

In exemplary embodiments, the processing apparatus 10 includes a sensor configured to detect a de-powdering state of the AM parts (e.g. a load cell to detect weight of the AM parts and/or powder cake and/or powder within the processing chamber 12). Such a sensor allows the processing apparatus 10 to be automated, which reduces the need for manual input to a de-powdering process (e.g. determining an appropriate cycle time, checking whether parts are de-powdered and re-running a de-powdering operation if checked parts are not fully de-powdered).

Referring again to Figure 1, the processing apparatus 10 is configured to induce a flow of fluid (e.g. air) and/or processing media within the processing chamber 12 for impacting one or more AM parts and/or a powder cake located within the processing chamber 12 with said fluid and/or processing media. In addition to the pumps 28 discussed above, the processing apparatus 10 of the illustrated embodiment includes a blower for inducing a flow of fluid within the processing chamber. The blower has a blower motor 50 and an impeller 52 driven by the motor. Providing a blower to induce a flow of fluid within the processing chamber 12 has been found increase the processing effectiveness. For example, in cases where processing media is provided in the processing chamber, such a flow of fluid provides a means for transferring kinetic energy to the processing media (e.g. in addition to or instead of pumps 28 which increases the force at which the processing media impacts AM parts or powder cakes).

In the illustrated embodiment, the processing apparatus 10 is configured to expel fluid (e.g. air) from the processing chamber 12 (e.g. via the blower). Expelling fluid from the processing chamber 12 prevents a build-up of fluid within the processing chamber 12 (e.g. in the case where fluid is also being input to the processing chamber 12 via one or more pumps 28). As will be described in more detail below, the processing apparatus 10 is configured so that expulsion of fluid from the processing chamber 12 via the blower creates a region of low pressure proximal the inlet arrangement 18 (e.g. proximal the single inlet portion 30) for urging a flow of processing media through the inlet arrangement 18 into the processing chamber 12. Such a region of low pressure has been found to urge processing media into the processing chamber 12, which increases its kinetic energy for impacting AM parts or powder cakes in the processing chamber 12.

The processing chamber 12 has an outlet tube 54 (as best shown in Figures 6 and 7) having a fixed end coupled to an end of the processing chamber 12 and a free end within the processing chamber 12, and the processing apparatus 10 is configured to expel fluid (e.g. air) from the processing chamber 12 via the outlet tube 54 (i.e. the blower is in fluid communication with the outlet tube 54). Having an outlet tube 54 with a free end within the processing chamber 12 means that fluid is removed from the middle of the processing chamber 12, rather than at a side or end of the processing chamber 12. Removing fluid from the middle of the processing chamber 12 has been found to facilitate formation of a low pressure region at an end of the processing chamber 12 (i.e. the end to which the fixed end of the outlet tube 54 is attached).

In the illustrated embodiment, the outlet tube 54 has a longitudinal axis which is aligned with a longitudinal axis of the processing chamber 12. Such an outlet tube 54 arrangement has been found to facilitate a swirling flow of fluid within the processing chamber 12, which improves processing efficiency either on its own, or in combination with processing media entrained within the swirling flow. However, in alternative embodiments, the outlet tube 54 is configured or arranged differently.

The processing apparatus also includes a blower pipe 53 which is connected to a filter 78 in the powder cabinet 46 (e.g. the same filter 78 as connected to powder return pipe 48 discussed above, or a different filter 78). Such a filter 78 prevents any small particles (e.g. powder or processing media) which are removed from the processing chamber 12 via the outlet tube 54 from being emitted to the atmosphere (e.g. where they could be inhaled by persons close to the processing apparatus 10). In alternative embodiments, a filter 78 is provided in the outlet tube 54, in the blower pipe 53 or is omitted entirely.

The processing apparatus 10 also includes a compressed fluid source 80 (e.g. as shown in Figure 7), such as a compressed air source), coupled to nozzles 56 configured to impact the one or more AM parts and/or powder cake with high pressure fluid (e.g. compressed air) from the compressed fluid source. Such compressed fluid nozzles 56 are useful for breaking apart a powder cake, moving parts to expose different faces to a flow of fluid/processing media, and/or for removing powder from or altering surface properties within cracks or crevices in AM parts.

In the illustrated embodiment, the nozzles 56 are arranged concentrically around an inner surface of the outlet tube 54. In alternative embodiments, the nozzles 56 are omitted or a single nozzle 56 is provided. In alternative embodiments, the nozzles 56 are arranged differently (e.g. on an outer surface of the outlet tube 54, or on the circumference 20 of the processing chamber 12).

In exemplary embodiments, one or more of the nozzles 56 includes an air flow amplifier. Having an air flow amplifier increases the volumetric flow rate and/or flow velocity through the nozzle 56, which has been found to increase processing performance.

In exemplary embodiments, one or more of the nozzles 56 is moveable (e.g. via a robotic arm). One or more of the nozzles 56 being moveable (e.g. via a robotic arm) allows high pressure fluid to be directed to regions of AM parts/powder cakes which are difficult to clean/de-powder (e.g. cracks/crevices which may be sheltered from a flow of processing media in the processing chamber 12).

As is most clearly illustrated in Figures 6 and 7, the processing chamber 12 has a rotating device 58 (e.g. in the form of a rotating drum) for receiving one or more AM parts and/or a powder cake containing one or more AM parts. The rotating device 58 is provided within an interior of the processing chamber 12 (i.e. within the cylindrical portion 14 and/or frustoconical portion 16 of the chamber walls 13). The rotating device 58 is configured to move one or more AM parts and/or a powder cake located within the rotating device 58 (e.g. via rotating device shaft 60 coupled to the rotating device 58). This movement has been found to be effective for agitation of powder and/or removal of powder from AM parts/powder cakes (either on its own, or in combination with a flow of fluid and/or processing media). Therefore, in exemplary embodiments, the processing apparatus 10 may only have a processing chamber 12 with a rotating device 58 (i.e. the inlet arrangement 18, blower and outlet tube 54 are omitted, and/or the processing chamber 12 is of different shape).

The movement of the rotating device 58 has also been found to be effective for exposing different faces of AM parts/powder cakes to a flow of fluid and/or processing media within the processing chamber 12. Exposing different faces of parts/powder cakes to a flow of fluid and/or processing media has been found to facilitate an automated removal of powder from the AM parts and/or powder cake and/or an automated alteration of surface properties of the one or more AM parts.

In the illustrated embodiment, the rotating device 58 is perforated to permit powder and/or fluid and/or processing media to be input to or output from the rotating device 58. The rotating device 58 being perforated prevents a build-up of removed powder and/or processing media within the rotating device 58, and allows a flow of fluid and/or processing media to be used to impact the AM parts/powder cakes receiving within the rotating device 58 (e.g. for removal of powder or alteration of surface properties).

In the illustrated embodiment, the processing apparatus is configured so that the rotating device 58 is removable from the processing chamber 12. The rotating device 58 being removable allows processing of larger parts or powder cakes (e.g. parts or powder cakes which would not fit in the rotating device) within the processing chamber 12. The rotating device 58 being removable also facilitates better processing efficiency where rotation of parts is not necessary (since removal of the rotating device 58 would lead to less impact on a flow of fluid and/or processing media within the processing chamber 12).

In the illustrated embodiment the rotating device 58 includes a device opening (i.e. defined by an open end of the rotating device 58) for input of AM parts or powder cakes to the rotating device 58 or removal of de-powdered or surface-altered parts from the rotating device 58. Referring now to Figures 8 and 9, the processing chamber 12 includes a chamber opening 62 for input of AM parts and/or powder cakes to the processing chamber 12 or removal of AM parts from the processing chamber 12. In the illustrated embodiment, the chamber opening 62 is provided on a side of the processing chamber 12. The processing chamber 12 also has a chamber door 64 for sealing the chamber opening 62 during a processing operation. In the illustrated embodiment, the chamber door 64 is configured to slide over the chamber opening 62, but in alternative embodiments, the chamber door 64 is hinged to pivot to open or close the chamber opening 62.

In exemplary embodiments, the processing apparatus 10 includes an automated mechanism for inserting and/or removing AM parts and/or powder cakes from the processing chamber 12 (e.g. via chamber opening 62). Having an automated mechanism for inserting and/or removing AM parts and/or powder cakes reduces the requirements for manual operation of the processing apparatus 10, which results in a more efficient processing operation.

In exemplary embodiments, the automated mechanism includes a robotic arm for movement of one or more AM parts and/or powder cakes. In exemplary embodiments, the automated mechanism comprises a vision system for determining the location of one or more AM parts and/or powder cakes.

In the illustrated embodiment, the processing apparatus 10 is housed within a cabinet 68. The cabinet 68 includes the user inputs 66 (as discussed above). The cabinet 68 also includes a cabinet opening 70 for access to the chamber opening 62 and chamber door 64. In the illustrated embodiment, the cabinet opening 70 is covered by a cabinet door 72 (which is hingedly mounted to the cabinet 68 in the illustrated embodiment). Alternatively, the cabinet door 72 may be omitted.

The processing apparatus also includes a manual blasting cabinet 74 on an opposite side of the cabinet 68 to the processing chamber 12. In alternative embodiments, the manual blasting cabinet 74 is omitted, or provided as a separate apparatus.

In exemplary embodiments, the processing apparatus 10 is configured to prevent generation of static electricity in the processing chamber 12 and/or cancel static electricity generated within the processing chamber 12. For example, the processing apparatus 10 may include one or more de-ionising devices. Preventing generation of static electricity and/or cancelling static energy reduces the likelihood of damage to the processing apparatus 10 and/or AM parts. Preventing generation of static electricity and/or cancelling static energy also prevents AM parts from being charged in ways which would be detrimental to further processing operations, such as coating operations.

Referring again to Figures 1 to 3, a method of processing one or more additively manufactured (AM) parts and/or a powder cake containing one or more AM parts using the processing apparatus 10 described above includes the following steps: locating one or more AM parts and/or a powder cake containing one or more AM parts in the processing chamber 12; providing processing media in the processing chamber 12; and creating a swirling flow path for said processing media within the processing chamber 12 for impacting the one or more AM parts and/or powder cake with the processing media.

The method also includes: introducing processing media to the processing chamber 12 via the inlet arrangement 18; and directing processing media from the inlet arrangement 18 along the circumference 20 of the processing chamber 12 to induce the swirling flow path for said processing media.

The method also includes: inducing a flow of fluid (e.g. air) through the processing chamber 12 (e.g. via the inlet arrangement 18 and/or blower); and entraining processing media in the flow of fluid.

In exemplary embodiments, the method also includes: expelling a flow of fluid from the processing chamber 12 (e.g. via outlet tube 54).

A second method of processing one or more additively manufactured (AM) parts and/or a powder cake containing one or more AM parts using the processing apparatus 10 described above includes the following steps (in addition to, or instead of the steps of the first method): locating one or more AM parts and/or a powder cake containing one or more AM parts in the processing chamber 12; providing two or more types of processing media in the processing chamber 12; and impacting the one or more AM parts and/or powder cake with the processing media; wherein the two or more types of processing media each have a different particle size and/or hardness and/or shape and/or other material property.

The use of two or more different types of processing media facilitates effective removal of powder from AM parts and/or surface modification of AM parts (e.g. smoothing). For example, using a coarse type of processing media has been found to more effectively break apart a powder cake or dislodge large chunks of powder from an AM part, whereas use of a fine type of processing media has been found to be more effective in removing powder from small cracks or crevices of an AM part. In addition, a combination of different types of processing media allows powder to be effectively removed from AM parts or powder cakes, and surfaces of the AM parts to be smoothed or roughened as desired in a single processing cycle (e.g. by using a metal or glass-based media for bulk powder removal and metal or ceramic-based media for alteration of surface properties).

In exemplary embodiments, the second method also involves introducing the two or more types of processing media to the processing chamber 12 via the inlet arrangement 18.

In exemplary embodiments, the second method also includes controlling the input of different types of processing media to the processing chamber 12 (e.g. via control system 76). For example, in exemplary embodiments controlling the input of different types of processing media includes: selecting one or more types of processing media for input to the processing chamber 12; altering a ratio of different types of processing media input to the processing chamber 12; altering a ratio of different types of processing media input to the processing chamber 12 during different stages of a processing operation; and/or determining one or more appropriate types of processing media based on a type of part.

Altering a ratio of different types of processing media input to the processing chamber 12 allows an optimal type of processing media or combination of different types to be used for a given processing operation. Furthermore, altering a ratio of different types of processing media input to the processing chamber 12 during different stages of a processing operation allows an optimal type of processing media or combination of different types to be used at each stage. For example, coarse particles have been found to be most suitable for breaking apart a powder cake in an initial "unpacking" stage, while fine particles have been found to be most suitable for removing powder from small cracks and crevices during a final "cleaning" stage.

Determining one or more appropriate types of processing media based on a type of part (e.g. via a lookup table stored in a control system 76) allows the optimal type of processing media or combination of different types to be used. If automated (e.g. via control system 76) this step also reduces the knowledge requirements of an operator (who may not know the optimal type(s) of processing media for a given part) and/or reduces human error (e.g. an operator may be less likely to select an incorrect part than an incorrect type of processing media).

Referring to again to Figures 3 to 5, a third method of processing one or more additively manufactured (AM) parts and/or a powder cake containing one or more AM parts using the processing apparatus 10 described above includes the following steps (in addition to, or instead of the steps of the first and/or second methods): locating one or more AM parts and/or a powder cake containing one or more AM parts in a processing chamber 12; providing processing media in the processing chamber 12; performing a processing operation wherein the one or more AM parts and/or powder cake are impacted by the processing media; and performing a separation operation for separating processing media from powder amassed during or after the processing operation (e.g. via the separating arrangement 36).

By separating/isolating powder it can be re-used in a new additive manufacturing build operation. Similarly, by separating/isolating processing media it can be re-used (e.g. stored in a tank for use in a subsequent processing operation, or recycled through the processing chamber 12 in the same processing operation).

In exemplary embodiments, the third method includes the step of transferring a mixture of processing media and removed powder from the processing chamber to the separating arrangement 36.

In exemplary embodiments, the third method includes vibrating and/or shaking and/or providing ultrasonic energy to at least a portion of the separating arrangement 36 (e.g. the screens 38). Vibrating/shaking/providing ultrasonic energy encourages a movement of processing media and powder through the separating arrangement 36.

In exemplary embodiments of the first, second or third methods described above, the processing media used to impact the one or more AM parts and/or powder cake includes metal processing media such as metal beads.

In exemplary embodiments of the first, second or third methods described above, the step of impacting the one or more AM parts and/or powder cake with the processing media is carried out while the one or more AM parts and/or powder cake are still warm (i.e. above room temperature) from an AM build operation.

Although the invention has been described in relation to one or more embodiments, it will be appreciated that various changes or modifications can be made without departing from the scope of the invention as defined in the appended claims. For example: the processing chamber 12 may have a different shape or configuration; the processing chamber may be pre-charged with the processing media, so that processing media is provided within the processing chamber 12 without an inlet arrangement 18 (e.g. processing media is provided in a tray or other container within the processing chamber 12); the processing chamber 12 and/or inlet arrangement 18 may have any type of configuration suitable for inducing a swirling flow of processing media within the processing chamber 12; the processing apparatus 10 may be configured to induce a non-swirling flow of processing media through the processing chamber (e.g. via an inlet arrangement 18 aligned with a longitudinal axis of the processing chamber 12); more or less than two types of processing media may be provided (with a corresponding change in the number of inlet pipes 24, processing media tanks 26 and screens 28); two or more types of processing media may be mixed within a single processing media tank 26; more or less pumps 28 may be used to control flow of fluid and processing media through the processing apparatus 10; the separating arrangement 36 may be alternatively configured (e.g. more or less screens 38 may be provided); the separating arrangement may be shaken/vibrated via a different mechanism (e.g. an eccentric drive mechanism, or ultrasonic energy source); the blower may be of different configuration; and the nozzles 56 and compressed fluid source may be omitted or alternatively configured/arranged.