[0002] The invention of this disclosure relates to the cleaning of 3D printed products such as 3D sand and binder printed products. More specifically, the invention of this disclosure is directed to an apparatus for cleaning impurities or debris such as excess sand from the surfaces of 3D sand and binder printed products that remain on the surfaces of the products after the printing process, by the application of a stream of shot over the surfaces of the products.

BACKGROUND ART

[0003] The concept of this disclosure is to provide an apparatus that utilizes a mild form of depositing shot or pellets of metallic, ceramic, or other equivalent types of materials in a stream over the surfaces of a product that has been prepared by a 3D sand and binder printing process.

[0004] The 3D sand and binder printing process is a known form of additive manufacturing that involves the blending of sand such as silica sand and a binder such as a dry acid binder in a mixture. The liquid binder is deposited on a layer of sand to form a mixture, and the mixture is built up on a flat surface, layer by layer and allowed to dry to produce a three-dimensional sand product such as a mold core. [0005] The apparatus is used to clean material such as excess sand and or debris from the exterior surfaces of the 3D printed product, thereby preparing the product or mold core for use in a molding process such as a metal molding process.

[0006] Additive manufacturing by 3D sand and binder printing has been in existence since approximately the early 1970s. Essentially, it is the reproduction by way of sand and binder and 3D printers, of digital images generated by computer and provide the preparation of models or products from the sand and binder that the user wishes to see from the standpoint of effectiveness, operative ability, aesthetics, before any final commercial product is developed or manufactured. In such printing, it is the application of what is generically called sand, but which may comprise various chemicals in the form of a dry acid binder, paste, and liquids, and which may be fortified with filling materials, such as solder paste, silica and silicates, and other types of materials or chemical ingredients that can add to the viscosity of the printing material, in order to build up the three-dimensional aspects of the product or component being formed, through such 3D sand printing procedures.

[0007] Where silica is an additive to the binder fluid being 3D printed, when the finished component is formed, it has a soft granular surface, on the formed product, that needs to be removed in order to achieve the finished version, of the desired product. Heretofore, it was common practice to use a brush, or other soft textured cleaner, that could be manually used to wipe the surface of the formed printed product such as a mold core, but if one is not careful in performing that procedure, the actual desired surface part of the mold core could also be removed, if too much pressure was applied during the cleaning process.

[0008] Hence, the concept of the current invention is to provide a precisely functioning apparatus, that applies just the right amount of steel, other metal, or ceramic beads, within a range of deposit, through what is identified as a shot cascading procedure, to the formed product or mold core, in order to effectively remove residual sand from the mold core, to complete its finishing. SUMMARY OF THE INVENTION

[0009] This invention generally relates to the surface cleaning of a formed or cast product, usually one that is to function as a model for a potential commercial product, and more specifically pertains to the cleansing of the surface of the printed formed product, generally deposited by the 3D sand and binder printing method, to form such a model of the desired product.

[0010] In the formation of the 3D printed product, the viscosity of the liquid deposited ingredient that is built up into a three-dimensional model, is rather essential. Usually, some form of filler material, that enhances the viscosity of the liquid being deposited, will include a viscosity enhancing ingredient that allows for the buildup of the forming product, through the sand and binder printing method. One such ingredient, as previously stated, is the use of silica, such as silicone, or fine sand, that is used in the formation of the desired design, which is generally deposited through the control of a computer, that regulates the deposit of the liquid material through the digital control of such a computer, in the printing of the formative product. When such a product is formed, the silica aspects of the product generally leaves a sandy or gritty type surface upon the formed product, that needs to be removed, so that the actual product as printed can be achieved, to provide that finished product desired by the applicant, through usage of such a printing process. That particular sandy surface needs to be removed, and can be attained by a variety of methods, such as through brushing, wiping, but the preferred embodiment provided herein is the usage of an apparatus that functions as a shot cascading device, depositing in a stream pelletized metal or ceramics or related materials onto the surface of the formed product, at just the proper pressure, volume, and quantity, in order to remove the gritty surface, and end up with the desired product through usage of this method. [0011] The apparatus of this invention includes a machine base that supports a contoured collecting bin for the shot material being deposited onto the product, and then as located therein a funnel like member that mates within the machine base, and upwardly of these assembled components is the shot supply hopper, in which the shot is deposited, and then discharged by gravity onto the product to be cleaned, during its functioning.

[0012] The shot supply hopper, upon actuation, includes a shot gate that opens to allow for a series of streams for falling of the steel shot media, downwardly, by gravity, onto the formed printed product held either by hand, or by other holding instrument, within the path of the falling shot, in order to attain that surface cleaning as desired. The uncleaned 3D printed sand product is held within the shot stream, and rolled around or moved in all angular directions, to position eventually all surfaces of the product within the falling shot stream. The falling cleanser shot media delivers the loose sand, within the 3D printed support material, off the surface of the product, thereby quickly performing the gross depowdering process without the need for any brushes, vacuum, or air blast, through labor or human participation, when cleansing the product surface. The shot media primarily used, in this embodiment, is the S230 steel shot. That particular shot has an average diameter, per particle, of around .025 in., and has been found most effective in cleansing most of the sand and binder printed products, as formed. The size of the shot can be varied depending on the size of the grains of sand to be removed from the surface of the product. The bottom of the shot supply hopper includes a pneumatic cylinder that actuates the shot gate on the hopper, and that shot gate uses eleven i in. diameter holes to drop the shot media at an approximate rate of 18.5 Ibs./min. (1.5-2 lbs./min. per hole) downwardly upon the positioned product, to achieve its cleansing. The size of the holes can be varied depending on the size of the shot. Larger size shot may be used to clean larger sized products, however, the system is most beneficial for smaller, detailed 3D printed products, that have been formed by the sand and binder printing process, and need to be cleaned to their desired dimensions. The rate of delivery, the size of the shot, and the time for holding the printed product under the shot gate, will vary depending upon the size of the product, but usually a time period of thirty seconds to four minutes has been found most effective, for small printed products through this method. Also, the variable tolerance for these parameters for the apparatus and its operations may be plus or minus 5 percent.

[0013] The machine base for the apparatus also includes a bin like member. And, within the bin like member is a funnel arrangement, rather complementary of insertion into the machine base and its bin, and the supplied shot, following cleansing, falls into the funnel, and out of its bottom into the bin of the machine base, where there is a cleansing and separation of the steel or ceramic shot, from the removed sand ingredient, as to be explained.

[0014] Upon the funnel is mounted, at its bottom exit point, a sand separator nozzle. That nozzle connects with a suction tube, to a vacuum source, and when the combined shot, and the removed sand ingredient, exit from the bottom of the funnel, the sand separator nozzle allows the steel shot to bypass said separator, but the lighter weight sand ingredient is sucked into the nozzle, by way of its suction tube, and delivers the separated sand to another collection point, where it can be cleansed and reused for further sand and binder printing, of other components. At the same time, the separated and collected shot, that drops downwardly within the bin of the machine base, is collected by a recycle pump, and is pumped through a shot recycle conduit, and back up into the shot supply hopper, for further and continuous usage, for further cleansing of formed product, during application of this apparatus.

[0015] The bottom of the previously defined shot supply hopper includes a pneumatic cylinder that actuates the shot gate, on demand, and upon its actuation, the shot gate opens to allow a series of streams of falling steel shot media from the gate, to be used for the cleansing process. The uncleaned 3D printed product is held in the shot stream, below the hopper and below the gate, and moved or rolled around to position all surfaces within the shot stream, as previously reviewed. [0016] The mixed sand and shot from the printed product during a cleansing drops such mixture to the bottom of the funnel, that cascades over the top of the sand separator nozzle. The heavier steel shot media passes over the nozzle and cascades downwardly into the machine base, and into the shot recycle pump maintained below the machine base, to posture it for recycling. The relatively lightweight sand, removed from the surface of the cleansing product, is drawn into the suction path of the sand separator nozzle, is collected in the formed vacuum, and is vacuumed out of the apparatus and to another area of collection. The sand ingredient can be cleansed and reused, for further sand and binder printing.

[0017] The cleaned metallic or ceramic shot which is deposited at the bottom of the machine base for the apparatus, is removed by the shot recycle pump, which is cyclically controlled below for a preset time, and then the shot material is pumped back to the shot supply hopper, at the top of the apparatus, for a preset time for repeat usage.

[0018] Thus, all the operator needs to do is initiate the operations of the apparatus, which allows for the controlled discharge of the shot material from the supply hopper by operation of the shot gate, deposit the same by gravity onto the held product to be cleaned, and then the apparatus completes the cycle by allowing the steel shot to fall downwardly into the machined base for pumping back into the hopper for recycling, while at the same time, the sand separated from the product is vacuumed into the nozzle at the bottom of the funnel, and through its suction tube for collection at a nearby location.

[0019] It is, therefore, the principal object of this invention to provide for the automation, through the use of a shot delivering means, to cleanse a 3D printed and formed product, without any further manual participation other than simply holding the product within the stream of the shot, during its usage. [0020] Another object of this invention is to provide a shot delivering apparatus that is regulated as to time, shot How, using a shot within a particular size and weight range, and depositing through the application of gravity to cleanse a sand and binder 3D printed product, without any further manual participation.

[0021] Still another object of this invention is to provide and simplify the method for cleansing of a sand and binder 3D printed product or model.

[0022] A further object of this invention is to provide a quick method for cleansing a printed product, under controlled conditions, that allow for the desired printed product to attain its determined dimensions in preparation for further testing and usage.

[0023] These and other objects may become more apparent to those skilled in the art upon review of the Summary of the Invention as provided herein, and upon undertaking a study of the Description of the Preferred Embodiment, in view of the Drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1 is a front isometric view of the shot cascading apparatus of this invention.

[0025] FIG. 2 is a rear isometric view of the shot cascading apparatus.

[0026] FIG. 3 is an isometric view of the exploded structures forming the shot delivering apparatus of this invention.

[0027] FIG. 4 is a view of the shot supply hopper, with the pneumatic operative shot gate at its bottom for controlled delivering the shot stream by gravity downwardly therefrom. [0028] FIG. 5A is an isometric view of the sand separator nozzle which is applied to the funnel structure of the apparatus, and showing a path for flow of the deposited shot, and surface removed sand, for the apparatus.

[0029] FIG. 5B is a perspective view of the sand separator nozzle and disclosing the removal of the deposited lightweight sand that is drawn in by vacuum from the apparatus.

[0030] FIG. 6 shows the separated shot that deposits within the machine base and the pump for recycling the shot back into its supply hopper, for reusage.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0031] As previously summarized, the concept of this invention is to provide a shot cascading apparatus for use in cleaning 3D sand and binder printed products, for example a mold core. As stated, this invention is designed to provide just the right and proper amount of shot in a falling stream, whether it be shot of a metallic type, ceramic type, or other equivalent type of small, pelletized materials, at a proper flow rate, applying a range of pressure upon the printed mold core, so as to eliminate any surface granular material, such as silica from the mold core, so that the finished mold core can be readily observed, handled, processed, to determine the physical structure and aesthetics of the mold core. The cleaned mold core may then be used for its intended purpose to cast or mold in abundance other finished products for commercial use, application, or sale.

[0032] The structural components of the shot cascading apparatus to be described are constructed of a material, such as a metal, a composite or other equivalent types of materials that provide the apparatus with sufficient structural strength to function in the intended manner to be described. [0033] A front perspective view of the shot cascading apparatus 1 of this disclosure is represented in FIG. 1. As represented, the apparatus 1 is comprised of a series of generally vertically aligned structures in the form of and comprising a machine base or framework 2. The base or framework 2 includes a supported bin 3 and which is designed for resting upon the ground surface, during usage and application. Sufficient clearance is provided between the bottom of the bin 3, and a shot recycling apparatus in the form of a shot recycle pump 4 that is useful for returning the spent and used shot back to its shot supply hopper 5 for reuse and in preparation for further cleansing of the printed product or mold core, during usage. Located within the bin 3 is a funnel like arrangement 6, added somewhat nested within the bin, as noted, and leaving some space between the bottom of the funnel 6 and the bottom of the bin 3, for locating other operative components of this apparatus, as will be described. As noted, the funnel 6 has a series of handles, as at 7, to provide for its lifting and removal from the bin 3, as becomes necessary for servicing or cleaning out of the apparatus, as represented in FIG. 3.

[0034] It can be seen that there is further structural support, as at 8, and lateral support 9 for holding in the hopper 5 in the position vertically above the combined funnel 6 and bin 3 of the apparatus. The hopper 5 has an open top and an interior volume that is configured to store a supply of shot.

[0035] At the bottom of a hopper 5 is located a gate mechanism 10, as also seen in FIG. 4. The gate mechanism 10 is in operative communication with the hopper 5 and the supply of shot stored in the hopper 5. The gate mechanism 10 may be pneumatically, manually, or electrically operated, in order to provide for shifting, through its operated lever arrangement 11 for opening fully or partially opening, or closing, the shot supply hopper 5 to adjust a rate of ejecting or dispensing a stream of shot from the hopper 5, as may be necessary during the operations of this apparatus. The gate mechanism 10 may be operable in some other equivalent manner to selectively adjust a stream of shot ejected or dispensed from the hopper 5. [0036] As previously reviewed, the hopper is designed for functioning as a shot gate, which when opened, allows a series of streams of falling steel or other material shot media downwardly, by gravity, and to impact upon the positioned 3D printed product or mold core, to provide for its surface cleansing.

[0037] Generally, as can be seen in FIG. 2, there is a substantial spacing or open area 12 between the bottom of the hopper 5, and the upper edges of the funnel 6, generally as noted at 12. It is in this open area 12 location where the operator may hold the printed product or mold core, either manually or with a tool, directly in the path of the steel shot media, ejected or dispensed from the hopper 5 or falling by gravity out of the hopper 5, in order to provide for an abrasive cleansing of the surface residue deposits of the silica or sand aspects of the printed material forming the product or mold core. The stream of shot, as desired, will only remove that surface content of the sand, and not imbed in any way into the actual formed product itself, which desires to be fully preserved for further usage in the development of a particular commercial product, as desired. For example, the 3D printed product may comprise the housing body of, for example, a gasoline dispensing nozzle, which eventually will be molded from aluminum, or other metal, and the predeveloped product can be sand and binder 3D printed through methods as previously described, and known in the art, so that an example and idea of the product configuration of the desired nozzle, can be readily observed, before the model component may be used, as for forming the mold, for casting of commercial products, when forming the gasoline dispensing nozzle housing for marketing. The operator may even hold the product for cleansing, within that spacing 12, or make use of other type of grasping instrument for supporting the product within the stream of the falling shot media, during a cleansing process. The operator can readily observe when the product is fully cleaned, upon its surface, because of the openness of the open area 12 of the apparatus, during its usage and operation, when the product is held in that spacing 12, while performing a surface cleansing process. [0038] The bottom of the shot gate 10 may have a series of openings, along its bottom surface 13, and the slide portion 11 of the gate mechanism lever cylinder, has a series of openings, which can be shifted into alignment fully or partially with the openings at the bottom surface of said gate 13, to control the amount of shot being discharged, from an opening in the bottom of the hopper 5, through the openings in the slide portion of the lever cylinder 11 and through the openings in the bottom surface 13 of the gate mechanism 10, during its functioning.

[0039] As can also be seen in FIG. 3, there is a sand separator apparatus comprising a sand separator nozzle 14 operatively associated with the bottom of the funnel 6. The sand separator nozzle 14 is connected with a suction tube 15 to which a vacuum source is applied, and functions as follows:

[0040] As can be seen in FIG. 5 A, the nozzle 14, which is secured by fasteners, located through an opening in the side of the funnel 6 shown in FIGS. 1 and 3, has an extending portion 16 that locates beneath the bottom opening of the funnel 6. The combined mixed sand, removed from the surface of a product being treated, and the metallic shot, dropped from the bottom of the funnel, cascades over the upper frontal surface of the separator nozzle, generally as indicated by the flow path B of the shot represented by the lines of circles in FIG. 5A, which exposes the mixed sand and shot to the lower opened end 17 of the nozzle, during its operations. The suction tube 15 connects with the integral fitting 18 at the upper end of the shown nozzle 14, and when the nozzle is operative, the heavier steel shot portion of the abrasive cleaner will fall downwardly past the open end 17 of the nozzle and downwardly from the lower edge of the shown nozzle, as noted by the path B, because the steel shot is of heavier consistency than the combination of the mixed sand and shot. While at the same time, the suction from the tube 15 will pull the relatively lightweight sand and draw it into the nozzle open end 17, as noted through the schematic of path A in FIG. 5B, and return the sand back to an area for collection, and reuse, in the component forming process. Thus, as can be readily understood, the heavier steel shot will fall off of the end of the nozzle open end 17, while the relatively lightweight sand is pulled back into the nozzle open end 17, for transfer, and collection, for reusage. Usually this type of granular material is relatively expensive, and it's cleaning and reusage is encouraged, from a cost standpoint.

[0041 ] On the other hand, since the steel shot falls to the bottom of the funnel 6, and down into the bin 3, it locates, by gravity, at the bottom end of the bin 3, and falls into the shot recycle pump 4, where it, likewise, is collected, and transferred through a shot recycle conduit 19 back to the top of and discharged into the shot supply hopper 5, for reapplication for a continuous cleansing process of the components being cleaned.

[0042] Providing a more detailed description of the apparatus 1 while referring to the FIGS. 1-6, the framework 2 of the apparatus is basically comprised of four vertical columns 22 that are relatively positioned in a three-dimensional, rectangular configuration. Each of the columns 22 is secured to the support bin 3 and the hopper 5 and fix the support bin 3 and hopper 5 in their relative, vertically spaced positions represented in FIGS. 1 and 2. This also fixes the gate mechanism 10 and the funnel 6 at their vertically spaced relative positions represented in the drawing FIGS. 1 and 2. Thus, the vertical columns 22 support the shot supply hopper 5 at its elevated position represented in FIGS. 1 and 2 with the gate mechanism 10 secured to the bottom of the hopper five. The gate mechanism 10 is held by the vertical columns 22 directly above the open area 12. The vertical columns 22 support the bin 3 and the funnel 6 directly below the open area 12. The shot recycling apparatus or shot recycling pump 4 is supported by the vertical columns 22 by the pump 4 being secured to the bottom of the bin 3.

[0043] The support bin 3 has an upper portion 23 having a rectangular configuration. The rectangular configuration is defined by four rectangular side walls 24 of the upper portion 23. The support bin 3 also has a lower portion 25 that is defined by four side walls 26 having trapezoidal configurations. The trapezoidal configurations of the four side walls 26 of the lower portion 25 of the bin 3 converge toward each other to a bottom opening at the bottom of the four trapezoidal sidewalls 26. The shot recycle pump 4 communicates with the bottom opening defined by the bottoms of the four trapezoidal sidewalls 26.

[0044] The four side walls 24 of the upper portion 23 of the bin 3 extend around and engage underneath four panels 27 that make up the configuration of the funnel 6. The side walls 24 support the funnel 6 and suspend the funnel 6 inside the bin 3 with there being an interior volume separating an exterior surface of the funnel 6 from an interior surface of the bin 3. As represented in FIG. 3, the four panels 27 of the funnel 6 each have a trapezoidal configuration. The four panels 27 are secured together with the trapezoidal configurations of the panels 27 converging downward toward each other as they extend downwardly from the side walls 24 of the bin 3. The four funnel panels 27 extend downwardly and converge toward each other to a bottom opening of the funnel 6 that is positioned just above the sand separator nozzle 14 described earlier. The sidewalls 24 of the bin upper portion 23 support and suspend the funnel 6 above the four sidewalls 26 of the bin lower portion 25 and define a space or the interior volume between the funnel panels 27 and the sidewalls 26 of the bin lower portion 25. The sand separator nozzle 14 is positioned in and housed in the space or in the interior volume. As represented in FIGS. 1 and 3, an opening 28 in one of the sidewalls 24 of the bin upper portion 23 provides access to the sand separator nozzle 14 in the space. The suction tube 15 and fitting 18 of the sand separator 14 pass through the opening 28.

[0045] As represented in FIGS. 1-4, the three-dimensional configuration of the hopper 5 is defined by 4 hopper side walls 29 having trapezoidal configurations. The four hopper side walls 29 are secured together with their trapezoidal configurations converging toward each other as they extend downwardly to a bottom opening of the hopper 5. The gate mechanism 10 is secured to the bottom of the hopper side walls 29 over the bottom opening. [0046] As represented in FIG. 4, the gate mechanism 10 has a plurality of openings 32 that pass through the gate mechanism and emerge from the bottom surface 13 of the gate mechanism. As described earlier, the holes or openings 32 have diameters of 1/2 inch to allow steel shot, for example S230 steel shot having an average diameter of 0.025 inch to easily pass through the openings 32. The lever slide portion 11 of the gate mechanism 10 also has holes of the same dimension passing through the slide portion 11. On operation of the gate mechanism 10, the holes through the slide portion 11 can be moved relative to the holes or openings 32 through the bottom surface 13 of the gate mechanism to allow a stream of shot 34 to easily flow from the hopper 15 through the gate mechanism 10, or to completely stop the flow of shot from the hopper 15 through the gate mechanism 10, or to adjust the rate of flow of a stream of shot 34 from the hopper 5 through the gate mechanism 10. In this manner, the gate mechanism 10 can be adjustably operated to adjust a rate at which a stream of shot 34 flows from the hopper 5 and is ejected as the stream of shot 34 from the gate mechanism 10. It is pointed out that although the stream of shot 34 is described as being ejected from the gate mechanism 10 by the force of gravity, the gate mechanism 10 could be modified to eject a stream of shot from the gate mechanism 10 by other than or in addition to the force of gravity. For example, a source of pneumatic pressure could be communicated with the gate mechanism 10 to eject a stream of shot from the gate mechanism by pneumatic pressure. With such a modification, it is not necessary that the stream of shot be directed downward and the stream of shot could be directed in a direction having a horizontal component.

[0047] The foregoing provides an example and an analysis of the structural components that make up the assembly of this shot cascading apparatus, and how it can be continuously used for cleaning components formed by a sand and binder 3D printer.

[0048] Variations or modifications of the subject matter of this invention may occur to those skilled in the art upon review of the development as explained herein. Such variations, if within the spirit of this invention, are intended to be encompassed within the scope of any claims to patent protection issuing upon this development. The summary of the invention as provided herein, and explanation as the preferred embodiment, and as depicted in the drawings, is generally set forth for illustrative purposes only. Such variations, if within the concept of this invention, are intended to be encompassed within the scope of any claims to patent protection issuing upon this invention.