Technical Field

The present disclosure relates to the field of investment casting. In particular, the present disclosure relates to an investment casting apparatus to be used during the investment casting process, and to methods of investment casting.

Background

Investment casting methods can be used to produce high quality, high precision metal components such as those used for aerospace or medical devices. This process can provide high accuracy, repeatable and cost effective components which require minimal post casting machining. Investment casting can also be used to produce complicated shapes that would be difficult to produce from other manufacturing methods.

For investment casting, a wax pattern is manufactured which corresponds to the end product to be manufactured. The wax pattern is then coated in investment materials. Typically, these are refractory ceramic materials which are applied in stages.

In the first stage, the wax pattern is dipped into a slurry of fine refractory material before being drained. This provides a‘prime coat’ of fine materials surrounding the wax pattern which preserves any fine details of the wax pattern. Less fine slurries may then be used to provide ‘back-up coats’ which add strength to the ceramic mould surrounding the wax (known as‘the investment’). In the second stage, often referred to as‘stuccoing’, ceramic materials are applied to the investment by placing it in a stream of incoming particulates. For example, the investment may be placed in a rainfall-sander. The investment is then left to dry so that the shell of investment materials hardens. This process may be repeated a number of times until a sufficient ceramic coating is achieved.

After the ceramic materials have been applied to the wax pattern, the investment is heated to melt the wax. The molten wax is then poured out of the investment thereby leaving a ceramic mould (‘shell covering’) with an internal cavity having a shape corresponding to that of the desired end product. The shell covering is then heated to further harden it, before molten metal is poured into the shell to fill the cavity. Once the metal in the cavity has set, a process of divesting occurs in which the shell is removed. This leaves the desired end metal product, which may then be subject to finishing. A limitation with investment casting is that it can be time-consuming and very costly. Also, there can be issues with the ceramic mould cracking when the wax inside is heated. As a result, it is not uncommon for wax patterns and their ceramic moulds to be manufactured which then end up not being used as they breaking during the de-waxing process.

Embodiments of the present disclosure seek to address these and other technical problems.

Summary

Aspects of the disclosure are set out in the independent claims and optional features are set out in the dependent claims. Aspects of the invention may be provided in conjunction with each other, and features of one aspect may be applied to other aspects.

In an aspect there is provided an investment casting method for simultaneous investment casting of two separate casting patterns. The method comprises applying investment materials to first and second casting patterns held on an investment casting pattern holding device. The first casting pattern is held by a first casting pattern holder of the device and the second casting pattern is held by a second casting pattern holder of the device. The investment materials are applied while rotating: (i) the first casting pattern holder relative to a body of the device about a first rotation axis to rotate the first casting pattern; and (ii) the second casting pattern holder about a second rotation axis different to the first rotation axis to rotate the second casting pattern.

In another aspect, there is provided an investment casting pattern holding device for holding casting patterns while investment materials are simultaneously applied to said casting patterns. The device comprises: (i) a body; (ii) a first casting pattern holder coupled to the body to be rotatable relative to the body about a first rotation axis; and (iii) a second casting pattern holder coupled to the body to be rotatable about a second rotation axis different to the first rotation axis.

Aspects may enable multiple casting patterns to be coated simultaneously to a high standard. One mechanical arm may be used while enabling a number of different casting patterns carried by that arm to be coated with investment materials. The casting patterns may each be rotated about their respective rotation axis to enable uniform application of ceramic materials to each part of the casting pattern. As they can rotate about their own rotation axis, the casting patterns may be held and rotated to avoid any issues associated with being in the shadow of another casting pattern. Each region of the surface of each casting pattern may therefore be exposed to oncoming investment materials for a same/similar amount of time. This may provide an even/uniform distribution of investment materials onto the casting patterns, which can provide a number of consistent layers of investment material on the casting pattern.

The provision of a casting pattern with a more even distribution of investment materials on it has been found to improve the investment casting process. For example, it may provide a more even dissipation of heat throughout the mould when subject to heating, such as when de-waxing or hardening. This may reduce the likelihood of moulds breaking during manufacturing, and thus reduce scrap rates. It has also been found that by following this approach, fewer layers of investment materials may need to be applied to the casting pattern before it is ready for heating. This may further reduce the volume of materials required and also the time taken.

Methods may comprise connecting the investment casting pattern holding device to an end effector of an independently rotatable and/or translatable mechanical arm. The mechanical arm may be used to control motion of the device, such as to place the device in an area for investment materials to be applied to it, e.g. in a stream or reservoir of particulates. For example, the mechanical arm may be operable to move the device into a slurry or rainfall sander. The mechanical arm may be a robotic arm. Additionally and/or alternatively to use of a mechanical arm, the device may be manipulated by another mechanical instrument controllable by a human, or directly controllable by a human, such as it may be a human arm which can manipulate the device.

Applying investment materials to the first and second casting patterns held on the investment casting pattern holding device may further comprise rotating the body of the device about a body rotation axis different to at least one of the first axis and the second axis. Rotation of the body about the body rotation axis may provide additional rotation to the casting pattern holders, e.g. so that they have a combined rotation about more than one rotation axis. Operation of the mechanical arm may provide further axes about which the device may rotate, yet while the device may rotate about these further axes, at least one rotational degree of freedom is provided by the first casting pattern holder. The first pattern holder provides at least one additional rotational degree of freedom to the device. For example, the first casting pattern holder may provide at least one additional rotational degree of freedom to those provided by the device itself and/or the mechanical arm. The second casting pattern holder may be rotated about the second rotation axis relative to the body of the device. The second casting pattern holder may provide at least one rotational degree of freedom for the device. For example, the second casting pattern holder may provide at least one additional rotational degree of freedom to those provided by the device itself and/or the mechanical arm.

Applying investment materials to the first and second casting patterns held on the investment casting pattern holding device may further comprise driving rotation of the body of the device about the body rotation axis. This driving rotation of the body may provide rotation of the first and/or second casting pattern holders about the first and second rotation axes respectively. One source of rotational input may be provided by the mechanical arm. This one source may give rise to rotational motion of both the first and the second casting pattern holder. Applying investment materials to the first and second casting patterns held on the investment casting pattern holding device may further comprise driving a rotation of the end effector to drive rotation of the body of the device about the body axis. The casting pattern holders are coupled to the body of the device so that rotation of the body of the device drives a rotation of the first and second casting pattern holders relative to the body of the device. The body may comprise a portion of the device which connects the mechanical arm to the casting pattern holders. The body of the device may comprise a portion of the device which is driven to drive rotation of the casting pattern holders. Applying investment materials may comprise controlling the mechanical arm to move the first and second casting patterns into a region where investment materials are applied to said casting patterns.

Applying the investment materials to the first and second casting patterns may comprise providing an orbital motion of at least one of the first and second casting pattern holders about the body of the device. Rotation of the body of the device about the body rotation axis may provide the orbital motion. For example, rotation of the casting pattern holders may cause the casting pattern holders to move along a path to provide an orbital motion of the holders. Rotation of the body of the device about the body rotation axis may provide an orbital motion of the first and second casting pattern holders about the body of the device. For example, the body may comprise a central wheel about which the casting pattern holders may orbit. The wheel may have a track which the casting pattern holders follow as they orbit around the wheel. For example, the track may be arranged to engage with the casting pattern holders so that rotation of the casting pattern holders causes the casting pattern holders to move their way along said track. Rotation of the mechanical arm may drive both the individual rotation of the first and second casting patterns and the orbital motion of at least one of the first and/or second casting pattern holders, e.g. an orbital motion about a portion of the body of the device. Apparatus of the present disclosure may provide a device adapted for connection to an end effector of an independently rotatable and/or translatable mechanical arm. The mechanical arm may comprise a robotic arm. The connection may be adapted to correspond to a connecting portion of the mechanical arm. The device may be rotatable about the connection. The connection may be arranged to enable the mechanical arm to manipulate the device (e.g. rotate and/or translate), such as to rotate the device so as to drive rotation of at least one of the body of the device, and/or the first and/or second casting pattern holders. The body may comprise a connection for connecting the device to the end effector of the mechanical arm. For example a portion of the body may be arranged to be connected to the end effector to receive rotational motion imparted via said end effector. That portion of the body may be connected to the first and/or second casting pattern holders. For example, a portion of the body may be connected to the first and/or second casting pattern holder which is arranged to both receive rotational motion imparted via the mechanical arm and to transmit said rotational motion to the first and/or second casting pattern holders. The device may be connectable to the mechanical arm to enable rotation of a portion of the mechanical arm to drive rotation of at least one of: (i) a portion of the body about a body rotation axis; (ii) the first casting pattern holder about the first rotation axis; and (iii) the second casting pattern holder about the second rotation axis.

The device may be arranged so that rotation of the body about the body rotation axis drives rotation of the first and second casting pattern holders about their respective rotation axes. Rotation of the body about the body rotation axis may be imparted by rotational movement of the end effector of the mechanical arm. One rotation of the mechanical arm may provide a plurality of rotations of the casting pattern holders. The device may be arranged so that rotation of the first and second casting pattern holders about their respective rotation axes provides an orbital motion of said casting pattern holders about the body.

The base of the device may comprise: (i) a carrier to which the first and second casting pattern holders are coupled; and (ii) a track which in use the first and second casting pattern holders move along as they rotate about the first and second rotation axis respectively. The track may follow a perimeter of a portion of a body of the device, e.g. the portion may be a central component about which the casting pattern holders may rotate. For example, the device may provide an epicyclic system in which: at least one of the first and second casting pattern holders provides a planet wheel of the epicyclic system; a portion of the body provides a carrier for the planet wheels of the epicyclic system; and the track provides a sun gear of the epicyclic system. One input rotation (e.g. of the end effector of the mechanical arm) may provide multiple output rotations (e.g. rotation of the first and second casting pattern holders about their respective axes and orbital motion of said holders about the wheel).

The second casting pattern holder may be coupled to the body to be rotatable relative to the body about the second rotation axis. For example, the first and/or second casting pattern holder may be coupled to the carrier. The first and/or second pattern holder may be coupled to the carrier so that they are rotatable relative to the carrier about their first and second rotational axis respectively.

The first casting pattern holder may be coupled to the body via a first bearing interface to enable rotation of the first casting pattern holder relative to the body. The second casting pattern holder may be coupled to the body via a second bearing interface to enable rotation of the second casting pattern holder relative to the body. For example, the bearing interface may be provided so that the casting pattern holders may rotate relative to the carrier to which they are coupled.

The apparatus may comprise a shield for shielding the body from investment material applied to the casting patterns during investment casting of the casting patterns. For example, the shield may be located in between the casting pattern holders and the wheel/track of the device. It may inhibit the flow of investment materials into a base region of the device where they may cause premature wear of the device, or impede rotational motion of components of the device.

The apparatus may comprise a first restraint for inhibiting movement of the first casting pattern holder along the first rotation axis. The apparatus may comprise a second restraint for inhibiting movement of the second casting pattern holder along the second rotation axis. The apparatus may comprise at least one further restraint for inhibiting movement of at least one of the wheel/track of the device from moving along an axis about which it rotates.

The apparatus may comprise a brake for inhibiting rotation of the track. The brake may comprise a friction brake. The apparatus may comprise an actuator for actuating the brake independently of the operation of the mechanical arm. For example, a pneumatic system may be provided for actuation of the brake. The brake may comprise a mount for mounting to the device and/or the mechanical arm. The mount may be independent of the connection between the mechanical arm and the device. For example, the mount may connect to an exterior surface of the mechanical arm. The brake may be arranged to engage with at least one of the track and/or the shield to impede rotation of the track. Operation of the brake may be used to control rotational motion of the first and/or second casting pattern holder and/or the orbital motion of said casting pattern holders about the body of the device.

The first and second casting pattern holder may each comprise a respective attachment means for holding and retaining in place a casting pattern in said casting pattern holder. For example, a clamp may be provided which is operable to retain the casting pattern in the casting pattern holder. A shaft associated with the casting pattern may be inserted into the casting pattern holder, and this shaft may be clamped to retain the casting pattern in the casting pattern holder.

The apparatus may comprise a suspender from which the holding device is suspendible. For example, this may be a hook from which the device may be manipulated e.g. picked up. The suspender may provide an additional attachment between the device and the mechanical arm, such as a means for holding the device to further facilitate lifting (e.g. translational) movement of the device by the mechanical arm.

In an aspect of the present disclosure, there is provided an investment casting pattern holding device for holding casting patterns while investment materials are simultaneously applied to said casting patterns. The device comprises: (i) a body; (ii) a first casting pattern holder coupled to the body to be rotatable relative to the body about a first rotation axis; and (iii) a second casting pattern holder coupled to the body to be rotatable relative to the body about a second rotation axis different to the first rotation axis. The device is arranged so that rotation of the first and second casting pattern holders about their respective rotation axes provides an orbital motion of said casting pattern holders about the body.

This may enable rotation of a first and second casting pattern when held on the device, as well as an orbital motion of these casting patterns. This may enable multiple casting patterns to be held by the device which can be subject to incoming investment materials, and they are rotated so that each surface of the casting pattern is subject to an even distribution of investment materials. The casting patterns also have an orbital motion so that the casting patterns may move into different regions so that each casting pattern moves into a region in which they directly receive incoming investment materials, and when in said region, the casting pattern is still rotated about its rotation axis so that the outer surfaces of the casting pattern receive a uniform distribution of investment materials.

In an aspect, there is provided an investment casting pattern holding device for holding casting patterns while investment materials are simultaneously applied to said casting patterns. The device comprises: (i) a body; (ii) a first casting pattern holder coupled to the body to be rotatable relative to the body about a first rotation axis; and (iii) a second casting pattern holder coupled to the body. The body is operable to be driven to rotate about a body rotation axis and to provide a rotation of the second casting pattern holder about a second rotation axis.

This may enable a first casting pattern to rotate about the first rotation axis, thereby receiving a uniform distribution of investment materials on its outer surface, with the outer surface of a second casting pattern also able to rotate relative to incoming investment materials by virtue of rotation of the body of the device itself. Both casting pattern holders may therefore be operable to receive a uniform distribution of investment materials on their outer surface without both of the first and second casting pattern holders being rotatable relative to the body of the device.

In an aspect, there is provided an investment casting pattern holding device for holding casting patterns while investment materials are simultaneously applied to said casting patterns. The device comprises: (i) a body; (ii) a first casting pattern holder coupled to the body to be rotatable relative to the body about a first rotation axis; and (iii) a second casting pattern holder coupled to the body to be rotatable relative to the body about a second rotation axis different to the first rotation axis. The first and second casting pattern holder are offset from one another to enable the device to be placed in a stream of investment materials coming from a first direction so that casting patterns held on both the first and second casting pattern holder receive incoming investment materials from said first direction.

This may enable a body to be provided which does not need to rotate. The rotational motion of casting patterns to provide the uniform distribution of investment materials on their outer surface may occur may be provided solely by the casting pattern holders. For example, the casting pattern holders may be arranged so that incoming investment materials from the first direction may provide the uniform distribution of the investment materials on the outer surfaces. The offset of the casting pattern holders may be such that each casting pattern holder has a direct line of sight to a source of incoming investment materials. For example a staggered layout or“v-shape” approach may be taken.

Aspects of the disclosure may provide a mechanical arm including investment casting pattern holding devices disclosed herein. For example, the investment casting pattern holding device may be provided as an integrated part of the mechanical arm or it may be provided as a separate attachment which is removable from the mechanical arm. For example, aspects may provide a kit of parts including a mechanical arm, and an investment casting pattern holding device of the present disclosure. The mechanical arm may be provided with a removable investment casting pattern holding device removably attached thereto.

For example, aspects may provide a mechanical arm for holding casting patterns while investment materials are simultaneously applied to said casting patterns. The arm comprises: (i) a body; (ii) a first casting pattern holder coupled to the body to be rotatable relative to the body about a first rotation axis; and (iii) a second casting pattern holder coupled to the body to be rotatable about a second rotation axis different to the first rotation axis. The arm may be configured to drive rotation of the first casting pattern holder about the first rotation axis and rotation of the second casting pattern holder about the second rotation axis.

Aspects of the disclosure may provide a computer program product comprising computer program instructions configured to program a controller to control operation of an investment casting pattern holding apparatus of the present disclosure to perform methods of the present disclosure.

Figures

Some embodiments will now be described, by way of example only, with reference to the figures, in which:

Fig. 1 is a schematic diagram of an example investment casting pattern holding device.

Fig. 2 is a schematic diagram of an example robotic arm for use with example investment casting pattern holding devices of the present disclosure.

Fig. 3 is a partial side-on view of an example investment casting pattern holding device.

Fig. 4 is an exploded view of a portion of a body of an example investment casting pattern holding device.

Figs. 5a to 5c are schematic diagrams of an example investment casting pattern holding device. Figs. 6a and 6b are schematic diagrams of example investment casting pattern holding devices.

In the drawings like reference numerals are used to indicate like elements.

Specific Description

Aspects of the present disclosure provide a device for holding casting patterns to which investment materials are to be applied. Each casting pattern is held by a casting pattern holder. At least one casting pattern holder can itself rotate in addition to rotational and/or translational movement of the device as a whole. A casting pattern held by that casting pattern holder may therefore rotate about a rotation axis associated with that casting pattern holder. This rotation of the casting pattern about the rotation axis is an additional rotation to any translational/rotational movement imparted to it through rotation/translation of the device itself. When investment materials are sprayed onto the casting patterns from one direction, the casting pattern holder may rotate about its rotation axis so that each region of an outer surface of the casting pattern held by that casting pattern holder receives an even amount of spray from the one direction.

Fig. 1 shows an example investment casting device 100. The device 100 includes a first casting pattern holder 121 arranged to hold a first casting pattern and a second casting pattern holder 122 arranged to hold a second casting pattern. A body of the device 100 includes a carrier 150, a wheel 151 , a shield 152 and a shaft 170. The shaft 170 includes a connection 171.

The connection 171 is located at one end of the shaft 170. At the other end of the shaft 170, the shaft 170 is connected to the carrier 150. The wheel 151 and the shield 152 are located between carrier 150 and the connection 171. The shaft 170 runs through a hole in the wheel 151 and the shield 152. The shield 152 is attached to the wheel 151 above the shield 152 (e.g. on the opposite side of the wheel 151 to the carrier 150). First and second portions of the carrier 150 extend radially outwards so that they extend beyond an edge of the wheel 151 and shield 152. The carrier 150 is shown as being cross-shaped, and the first and second portions are regions of the cross which extend radially outward beyond a perimeter of the wheel 151 and the shield 152. The first casting pattern holder 121 is coupled to the first portion of the carrier 150. The first casting pattern holder 121 is carried on (e.g. is connected to or includes) a first gear 181. The second casting pattern holder 122 is connected to the second portion of the carrier 150. The second casting pattern holder 122 is carried on (e.g. is connected to or includes) a second gear 182. The first gear 181 is arranged between the first portion of the carrier 150 and the first casting pattern holder 121. The second gear 182 is arranged to be between the second portion of the carrier 150 and the second casting pattern holder 122.

The connection 171 is arranged to provide a coupling between the shaft 170 and a mechanical arm 110. It provides a coupling so that a rotation applied by the mechanical arm 110 is operable to drive a rotation of the shaft 170. This rotation of the shaft 170 is in a plane parallel to that of the carrier 150, e.g. in a plane perpendicular to a longitudinal axis of the shaft 170. The connection 171 is arranged to fit within a corresponding recess in the mechanical arm 110, e.g. as shown in Fig. 1 , the connection 171 may be a cross-bar which an end effector of the mechanical arm 110 engages with. The connection 171 enables the device 100 to be held and rotated by the mechanical arm 110. With reference to Fig. 5b, a connecting region 112 of a mechanical arm 110 is shown. The connecting region 112 is in the form of a recess with a u-shape such that a bar of the connection 171 may be inserted into the recess. The recess may then enable the arm 110 to hold the device 100 and also to drive rotation of it.

The shaft 170 is arranged to rotate with the connection 171 when the connection 171 is driven to rotate by the mechanical arm 110. Rotation of the shaft 170 drives rotation of the carrier 150. That is, rotation of a portion of the mechanical arm 110 drives the connection 171 to rotate, which in turn drives the shaft 170 to rotate which drives the carrier 150 to rotate. The shaft 170 is rotationally separated from the wheel 151 and the shield 152, so that rotation of the shaft 170 does not drive rotation of the wheel 151 and shield 152. Rotation imparted by the mechanical arm 110 may provide rotation of the carrier 150 relative to the wheel 151 and the shield 152. This imparted rotation by a portion of the mechanical arm 110 may also provide rotation of the first and/or second casting pattern holders relative to the body of the device.

The carrier 150 is arranged to be driven to rotate by rotation of the shaft 170. The first casting pattern holder 121 is coupled to the carrier 150 to enable rotation of the first casting pattern holder 121 about a first rotation axis relative to the carrier 150. The second casting pattern holder 122 is coupled to the carrier 150 to enable rotation of the second casting pattern holder 122 about a second rotation axis relative to the carrier 150. That is, the carrier 150 is arranged so that it may be stationary, e.g. not rotating, while at least one of the casting pattern holders is rotating. A central portion of the carrier 150 is connected to the shaft 170 with regions extending radially outwards beyond the wheel 151 and shield 152. The first and second casting pattern holders are coupled to the carrier 150 in regions radially outward from the wheel 151. The carrier 150 may rotate to provide orbital motion of the first and second casting pattern holders about the wheel 151 in addition to rotational movement of the casting pattern holders about their own respective rotational axis.

The first casting pattern holder 121 is connected to the first gear 181 so that rotation of the first gear 181 drives a corresponding rotation of the first casting pattern holder 121. The first gear 181 is arranged to engage with the wheel 151 to provide rotation of the first casting pattern holder 121 about the first rotation axis. The first gear 181 is arranged to be engaged with the wheel 151 so that the rotation of the carrier 150 provides an interaction between the first gear 181 and the wheel 151 which drives a rotation of the first casting pattern holder 121 about the first rotation axis. The first gear 181 has a toothed outer profile for engagement with a corresponding toothed section of the wheel 151.

The second casting pattern holder 122 is connected to the second gear 182 so that rotation of the second gear 182 drives a corresponding rotation of the second casting pattern holder 122. The second gear 182 is arranged to engage with the wheel 151 to provide rotation of the second casting pattern holder 122 about the second rotation axis. The second gear 182 is arranged to be engaged with the wheel 151 so that the rotation of the carrier 150 provides an interaction between the second gear 182 and the wheel 151 which drives a rotation of the second casting pattern holder 122 about the second rotation axis. The second gear 182 has a toothed outer profile for engagement with a corresponding toothed section of the wheel 151.

The wheel 151 is connected to the carrier 150 to enable it to rotate relative to the carrier 150. That is, so that rotation of the carrier 150 does not directly drive rotation of the wheel 151. The wheel 151 may rotate about a body rotation axis running through its centre. Rotation of the wheel 151 may be driven by interaction between the wheel 151 and rotating gears engaged with the wheel 151. The device 100 may include means for impeding rotation of the wheel 151 to control orbital motion of the casting pattern holders about the wheel 151 in response to rotation of the casting pattern holders about their respective rotation axes. An outer perimeter of the wheel 151 is toothed for interaction with the toothed gears. The wheel 151 provides a track along which the gears, and thus the casting pattern holders, may move along as they rotate about their respective rotation axes.

The shield 152 is attached to the wheel 151 to protect the wheel 151 and other components from investment materials applied to the casting patterns during investment casting of the casting patterns. The shield 152 may span a greater width than the wheel 151 so that toothed sections around the edge of the wheel 151 are also shielded from investment materials. The shield 152 is attached to the wheel 151 so that the two rotate together. That is, if the wheel 151 is driven to rotate, it will rotate the shield 152 with it and vice versa. Impeding rotation of the wheel 151 may therefore be performed by impeding rotation of the shield 152.

Fig. 2 shows an example apparatus 200 which may be used to assist in applying investment materials to the casting patterns held by an investment casting device 100 of the present disclosure. The apparatus 200 includes a mechanical arm 210. An end effector of the mechanical arm 210 is shown which has a connecting portion 212. The connecting portion 212 has a recess shape when viewed side on. That is, it has a groove into which a T-bar 271 is inserted and secured thereto. As shown, the T-bar 271 is of a rotating device on the end of which a casting pattern 240 is mounted. The T-bar 271 is connected to a shaft 270 onto which the casting pattern 240 is mounted. In the example shown, the rotating device is not an investment casting pattern holding device of the present disclosure. It only has one casting pattern holder. However, investment casting pattern holding devices of the present disclosure, such as the investment casting pattern holding device 100 of Fig. 1 may be attached to this mechanical arm 210 in the same manner as the rotating device shown in Fig. 2.

In operation, casting patterns are loaded in the investment casting pattern holding device 100. Typically, each casting pattern will have an attachment shaft extending from the desired casting pattern so that the pattern can be clamped by the casting pattern holder. The attachment shaft is inserted into the casting pattern holder and clamped so that it is ready for application of investment materials. The device 100 is connected to an end effector of the mechanical arm 110. For example, as with the rotating device of Fig. 2, the connection 171 of the shaft 170 of the device 100 may be inserted into a corresponding recess of the end effector of the mechanical arm 110. The mechanical arm 110 is used to place the device 100 in a selected location for investment casting to be applied thereto. This may involve placing the device 100 in a slurry of fine refractory materials, or placing it in a rainfall-sander.

The mechanical arm 110 is actuated to drive a rotation of the device 100. The mechanical arm 110 drives rotation of the carrier 150 (e.g. using the connection 171 and the shaft 170). Rotation of the carrier 150 provides an orbital motion of the casting pattern holders about the track of the wheel 151. As the carrier 150 rotates it causes the gears of the casting pattern holders to rotate as they roll along the track with their teeth engaging with the teeth of the track. This provides a localised rotation of each casting pattern holder about its respective rotation axis. The casting pattern holders and thus the casting patterns both rotate about their rotation axis and orbital about an orbital axis of the device 100. As such, an even distribution of investment materials may be applied to the outer surface of each of the casting patterns. The combination of the orbital motion of the carrier 150/casting pattern holders and the individual localised rotation of each casting pattern holder is provided by one source of input rotational motion from the mechanical arm 110.

Also shown in Fig. 1 is a braking system 160 which includes a contact element 161. A connecting portion 115 of the end effector of the mechanical arm 110 is also shown.

The braking system 160 includes an attachment for attaching to the connecting portion 115 of the end effector. The attachment is attached to the end effector using a plate which extends around the end effector, and fasteners for securing the plate to the end effector. The braking system 160 includes pneumatic cylinders and attached tubing, both of which are held in place against the end effector. Extending from the end effector towards the shield 152 is a pair of extension shafts. At the opposite end of each extension shaft to the end effector, a contact element 161 is attached.

The braking system 160 is arranged to control extension of the extension shafts. The braking system 160 is operable to move the extension shafts from a position in which the contact element 161 is not in contact with the shield 152, to a position in which the contact element 161 is in contact with the shield 152.

The contact element 161 is arranged to provide increased friction between the extension shafts and the shield 152. Operation of the braking system 160 to bring the contact elements into contact with the shield 152 enables rotation of the shield 152 and wheel 151 to be inhibited. The contact element 161 may therefore act as a friction brake which is actuated by a pneumatic system.

In operation, the braking system 160 may be used to select rotational dynamics of the system. It is to be appreciated in the context of this disclosure that motion of the carrier 150, the casting pattern holders and the wheel 151 may correspond to an epicyclic arrangement of carrier 150, planet wheel and sun wheels respectively. Without the braking system 160 actuated, the three are each free to rotate, which will depending on chosen gear ratios, provide a selected speed for orbital motion and rotational motion of the casting planet holders. For example, under certain circumstances, without the braking system 160 actuated, rotation of the carrier 150 may drive a rotational motion of the casting pattern holders, but no, or limited, orbital motion of the casting pattern holders. Actuation of the braking system 160 to bring the contact element 161 into contact with the shield 152/wheel 151 may prevent rotation of the wheel 151. In turn, this may cause increased speed for the orbital motion of the casting pattern holders about the wheel 151.

Further examples of an investment casting pattern holding device 100 will now be described with reference to Figs. 3 to 5.

Fig. 3 shows a side on view of a section of an investment casting pattern holding device 100, such as the device 100 shown in Fig. 1. As such, parts corresponding to those discussed above for Fig. 1 will not be discussed again.

The shaft 170 of the device 100 is connected to the mechanical arm 110 via the connection 171. A central bush 153 is provided, which is secured to the carrier 150 so that the two rotate together. The wheel 151 and shield 152 may rotate about the shaft 170 using the bush 153. As shown, a plurality of dowel pins 155 are provided which secure the bush 153 to the carrier 150. The shaft 170 extends through the bush 153 and is secured to the carrier 150 by an attachment bolt 154. The shaft 170 may rotate the carrier 150 without imparting any rotational movement into the carrier 150 and the shield 152. A retaining means such as central circlip 156 is provided on the shaft 170 to permit rotation about/relative to the shaft 170 of the shield 152 and/or the wheel 151 whilst inhibiting movement along the shaft 170. This arrangement of an example body of the device 100 is shown in an exploded view in Fig. 4.

An example for the connection 171 of the first casting pattern holder 121 to the carrier 150 is shown in more detail on the left hand side of Fig. 3. The first casting pattern holder 121 has an external profile shaped to correspond to an internal profile of the gear 181. For example, the first gear 181 may have a hole through which the first pattern holder 121 extends, and an inner profile of the gear 181 associated with this hole includes a key which engages with the outer profile of the casting pattern holder 121. The casting pattern holder 121 and the gear 181 may therefore rotate together. A first circlip 123 and a second circlip 124 are provided to prevent movement of the casting pattern holder 121 along its rotation axis, e.g. perpendicular to the first gear 181.

A bearing interface 126 is provided for the first casting pattern holder 121. The casting pattern holder 121 is coupled to the carrier 150 so that the first casting pattern holder 121 may rotate relative to the carrier 150 about the first rotation axis. The casting pattern holder 121 may extend through a hole in the carrier 150. The bearing interface 126 is provided to facilitate relative rotation of the casting pattern holder 121. As shown, a bearing housing 127 is connected to the carrier 150 by an attachment 128, and a lower circlip 125 is provided to permit relative rotation whilst inhibiting movement along the first rotation axis.

The end effector of the mechanical arm 110 may engage with the connection 171 as discussed above. Additionally, a locking mechanism such as a pin may be applied through a hole in the top of the shaft 170. This may further secure the mechanical arm 110 to the device 100. Figs. 5a to 5c show examples of the device 100 when attached to the end effector of the mechanical arm 110.

The connection 171 may facilitate the device 100 to be rotated (e.g. tilted) relative to the mechanical arm 110. For example, the device 100 may stay flat, while the arm 110 is tilted relative to the device 100. As shown in Fig. 5a, the device 100 may be held flat with the arm 110 angled at 45 degrees to vertical, whereas in Fig. 5b, the arm 110 is angled parallel to vertical. The connection 171 may facilitate such relative rotation of the device 100 relative to the mechanical arm 110 carrying it. Fig. 5c shows an example device 100 in which a suspender 175 is included. The suspender 175 may be used to hold/lift the device 100. For example, a component of the mechanical arm 110 to which the device 100 is to be engaged may use the suspender 175 to facilitate lifting and moving of the device 100.

Specific examples of investment casting rotation devices have been described above. However, it is to be appreciated in the context of the present disclosure that certain features described are not to be considered limiting, and that other arrangements are envisaged. Figs 6a and 6b illustrate other examples of investment casting rotation devices which differ from those described above in some way.

Fig. 6a shows an investment casting rotation device 601 having a carrier 650 to which a first casting pattern holder 621 is coupled. As shown, a first gear 681 is provided for engaging with a wheel 751 of the device 601. Also shown is a second casting pattern holder 622.

The second casting pattern holder 622 is shown in the centre of the wheel 751 , although it is to be appreciated that it could be located at any suitable location of the device 601. The second casting pattern is secured to the carrier 650 of the device 601 so that rotation of the carrier 650 about a body rotation axis will also provide a rotation of the second casting pattern holder 622. The remaining components are arranged substantially as disclosed above and so will not be described again.

In operation, the carrier 650 is driven to rotate, e.g. by a mechanical arm 110 connected to the device 601. Rotation of the carrier 650 will drive rotation of the first casting pattern holder 621 about the first rotation axis. It will also drive a rotation of the second casting pattern holder 622 about a second rotation device different to the first rotation device. As the second casting pattern holder 622 is coupled to the body of the device 601 to rotate with the body, the second casting pattern holder 622 will rotate about the body rotation axis. When applying investment materials to casting patterns held by the device, both casting patterns will rotate to enable their surfaces to receive a more uniform distribution of investment materials, as there will be fewer issues associated with shadowing. Other arrangements of the first and second casting pattern holders may be provided, such as both casting pattern holders being carried by the same region of the carrier 650, with one fixedly attached to the carrier 650, and the other coupled to the carrier 650 to permit relative rotation of that holder relative to the carrier 650.

Fig. 6b shows another example of an investment casting pattern holding device 602 in which a carrier 650 is provided to which a plurality of investment casting pattern holders are attached. As shown in Fig. 6b the device 602 includes a first investment casting pattern holder 621 , a second investment casting pattern holder 622, a third investment casting pattern holder 623 and a fourth investment casting pattern holder 624.

The four casting pattern holders are arranged in a line. However, it is to be appreciated that they may be arranged in any suitable arrangement in which incoming investment materials from a first direction may have a direct line of sight towards each of the casting pattern holders. For example, each casting pattern holder may be laterally offset and also offset in another direction, such as adopting a v-shape.

Each of the casting pattern holders are rotatable relative to the carrier 650 about a respective rotation axis. The carrier 650 may therefore not rotate whilst the pattern holders rotate relative to the carrier 650 so that casting patterns held by them may present each surface to incoming investment materials uniformly. For example, the device 602 may be placed in a region for investment materials to be applied, such as by a mechanical arm. The investment materials may then be applied while the casting pattern holders are driven to rotate. The casting pattern holders may be driven in a geared manner as described above, wherein each of the holders is driven to rotate based on one incoming rotation applied via a mechanical arm. Alternatively and/or additionally, casting pattern holders may be attached to their own source of incoming rotational motion, such as a rotating shaft of a mechanical arm as described above, or by connection to independent respective motors for driving rotary motion.

Embodiments of the present disclosure may prevent an uneven distribution of investment materials on the surface of the casting patterns may arise. The present inventors have found that by maintaining a consistent and even distribution of investment materials on the surface of the casting patterns, improved heat distribution may occur when heating the casting patterns in the investment casting process. This may reduce the number of unsuccessful attempts at investment casting and may also reduce waste and the number of layers needed before the casting pattern is ready to be heated and used to provide the desired shape. This may in turn reduce time and cost of investment casting.

Other examples of investment casting pattern holding devices are also envisaged. For example, some of the above examples have described epicyclic arrangements in which a carrier is driven to rotate which in turn provides orbital motion of planet wheel casting pattern holders about a sun wheel. However, it is to be appreciated in the context of this disclosure that any suitable epicyclic arrangement could be used which may enable the first and/or second casting pattern holder to rotate about the first and second rotation axis respectively, and optionally to provide orbital motion of the holders about the body. For example, an outer ring could also be provided. The ring may be driven instead of the carrier, or alternatively the sun gear may be driven whilst still providing the relevant rotational and/or orbital motion of the casting pattern holders.

It is to be appreciated in the context of the present disclosure that where an epicyclic arrangement is adopted, the gear ratios may be selected accordingly. For example, the rotational inertia of components may also be selected to provide a desired rotational behaviour when driven at a selected rotational speed. For example, the arrangement could be selected so that driving rotation of the carrier at a constant torque provides both orbital motion and rotational motion of the first and/or second casting pattern holders (e.g. without the need for a braking system). The ratios may be selected so that for one complete orbit of a casting pattern holder about the wheel, there may be a selected number of rotational revolutions of the casting pattern holder about its rotation axis. For example, this may be an integer number; it may be more than one; it may be less than one. In some examples, it may be selected to provide a non-integer number of rotations, so that in subsequent orbits, when the pattern holder is at a selected point in its orbit, a different region of its surface is facing the source of incoming investment materials than when it was previously at that position in an orbit.

Examples have been described in which a rotational motion from the mechanical arm is used to drive motion of the casting pattern holders. In particular, examples used toothed connections between rotating parts to impart rotational and orbital motion into the casting pattern holders. However, other arrangements are also considered. For example, at least one independent motor (e.g. pneumatic or electric) may be provided for imparting rotational motion. The motor may be connected to each casting pattern holder directly and/or it may be connected to the carrier in a similar manner to how the mechanical arm may drive a carrier of the device. It is to be appreciated that in embodiments in which a motor is directly connected to the casting pattern holder directly, a carrier may not be needed. For example the casting pattern holders may then rotate independently relative to a body of the device. Additionally and/or alternatively, instead of the use of toothed gears and/or a toothed wheel, friction or toothed pulley systems may be used for transmitting rotational motion. For example, the device may include toothed/friction pulleys to provide the relevant rotational and/or orbital motion of the pattern holders.

The carrier has been shown in a cross-shape in which each arm accommodates one holder. However, this is not to be considered limiting, as other shapes may be considered. For example, the carrier may be circular, or it may have multiple casting pattern holders per each portion of the carrier which extends radially outward from the wheel.

Bushes, bearing interfaces and circlips have been described herein. However, it is to be appreciated in the context of the present disclosure that their inclusion is merely exemplary, and that any other suitable component which facilitates the relevant rotational movement and/or impedes the relevant translational movement may be used. For example, where a circlip and/or bushing are provided between the wheel/shield and the shaft, this same functionality may be provided by having a larger hole in the wheel/shield so that they do not touch the shaft. They will be constrained in place by their interaction with the pattern holders. Likewise, where the bearing interface is shown as being located beneath the carrier (e.g. on the opposite side of the carrier to the pattern holders) this is not to be considered limiting as it could be provided in any suitable location for facilitating rotation of the pattern holder relative to the body of the device. Suitable components for facilitating relative rotation may include bearing interfaces, thrust bearings - sometimes multiple bearings may be used where high loads are expected, also bushings or air bearings could be used. Examples include a shield connected to the wheel. However, it is to be appreciated that other arrangements are envisaged which provide similar functionality. For example, the shield may be integrated with the wheel (e.g. they may be one component, wherein the top of the component is shaped to provide the relevant shielding functionality). The shield may not be necessary at all. For example, where toothed connections are not used, the risk of material ingress into moving parts may no longer exist.

Examples include description of the connection between the shaft and the mechanical arm, wherein the connection is in the form of a T-bar arrangement. However, other options are possible such as the connection being a screw attachment between the shaft and the mechanical arm. Other suitable connections may include a ball lock attachment, a pin lock attachment, a magnetic lock and/or a vacuum lock. It is to be appreciated that any suitable connection may be used which may facilitate the mechanical arm to transmit rotational and/or translation motion to the device, such as to drive rotation of casting pattern holders relative to the body of the device about their respective rotation axes. Preferably, the connection may permit rotation (e.g. tilting) of the device relative to the mechanical arm.

The braking system described herein has been described with reference to pneumatic actuation. However, it is to be appreciated that any suitable braking system may be used which is operable to inhibit rotation of at least one rotating component of the device. For example, any braking system may be used which may inhibit rotation of one component of the epicyclic arrangement to provide or vary rotation (e.g. orbital motion) of another component of the epicyclic arrangement, such as to inhibit rotation of a sun gear (or a ring or carrier) to facilitate rotation of the pattern holders about their rotation axis, and optionally to facilitate them orbiting around the wheel. Other suitable restraining devices may include a pin lock arrangement, or the use of a fixed gear arrangement in the device. Alternatively and/or additionally, a magnetic or vacuum lock may be used to provide this functionality.

Reference has been made to investment materials which are to be applied to the casting patterns. It is to be appreciated that this may include any suitable material for use when investment casting. For example, this may include refractory materials, such as ceramic materials such as stucco. These particles may be in a suitable form, such as held in suspension in a slurry, or applied in a stream of particles, e.g. by a rainfall sander. Likewise, although casting patterns have been described as being manufactured out of wax, they may be any suitable material for use when investment casting. Materials such as plastic may be used. Whilst examples described have been described with regards to an incoming stream of particles, in particular from one direction, it is to be appreciated in the context of the present disclosure that this is not limiting. For example, the particles may be applied to the casting patterns when coming from more than one direction. The relative rotation of the device may still provide advantageous effects in this case as it may enable a more uniform application of materials to the surface of the casting patterns by varying which sides are exposed. Examples may have been described with reference to incoming investment materials, such as when placed in a rainfall sander, but they may also be beneficial when e.g. dunking the device in a slurry of investment materials. For example, the relative rotation of the holders to the body of the device may help with turbulence and interference type effects which may occur with the holders being placed in a fluid reservoir.

Examples have been described with reference to a mechanical arm such as a robotic arm. However, it is to be appreciated that advantageous effects of the present disclosure may also occur when other suitable manipulation of the device is provided, e.g. by another machine/alternative mechanical device and/or when the device is manipulated by a human user. For examples where machinery such as a mechanical arm is used to control/manipulate the device, a controller (e.g. a computer) may be provided for controlling operation of the mechanical arm. The controller may be configured to control rotation of the first and/or second casting pattern holders based on controlling rotation of the relevant component of the mechanical arm. For example, the controller may control the arm to impart rotation to the casting pattern holders in the event that a signal is received indicating that investment materials are to be applied and that the relative rotation of the holders to the body of the device is desired.

It will be appreciated from the discussion above that the embodiments shown in the figures are merely exemplary, and include features which may be generalised, removed or replaced as described herein and as set out in the claims. With reference to the drawings in general, it will be appreciated that schematic functional block diagrams are used to indicate functionality of systems and apparatus described herein. The function of one or more of the elements shown in the drawings may be further subdivided, and/or distributed throughout apparatus of the disclosure. In some embodiments the function of one or more elements shown in the drawings may be integrated into a single functional unit.

As will be appreciated by the skilled reader in the context of the present disclosure, each of the examples described herein may be implemented in a variety of different ways. Any feature of any aspects of the disclosure may be combined with any of the other aspects of the disclosure. For example method aspects may be combined with apparatus aspects, and features described with reference to the operation of particular elements of apparatus may be provided in methods which do not use those particular types of apparatus. In addition, each of the features of each of the embodiments is intended to be separable from the features which it is described in combination with, unless it is expressly stated that some other feature is essential to its operation. Each of these separable features may of course be combined with any of the other features of the embodiment in which it is described, or with any of the other features or combination of features of any of the other embodiments described herein. Furthermore, equivalents and modifications not described above may also be employed without departing from the invention. Other examples and variations of the disclosure will be apparent to the skilled addressee in the context of the present disclosure.