WO2022225783A1

WO2022225783A1 - Method and system for additive manufacturing

Info

Publication number: WO2022225783A1
Application number: PCT/US2022/024801
Authority: WO
Inventors: John BOORADY; Daniel Hutchinson; Gary BURCH; Michael Demeo; Owen WEGMAN
Original assignee: Postprocess Technologies, Inc.
Priority date: 2021-04-21
Filing date: 2022-04-14
Publication date: 2022-10-27

Abstract

A system and method are disclosed for additively manufacturing an object to facilitate smoothing a surface of the object. An evaluation is made whether positioning the object with a specific orientation in a finishing apparatus is desirable and if so, the object is printed with an alignment feature. After printing the object, the object is positioned in the finishing apparatus using the alignment feature to provide the specific orientation in the finishing apparatus and the finishing apparatus is operated to smooth the surface of object. After smoothing the surface of the object, the alignment feature may be removed if necessary.

Description

METHOD AND SYSTEM FOR ADDITIVE MANUFACTURING

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of the filing date under 35 U.S.C. § 119(e) of U.S. Provisional Application Serial No. 63/177,550 filed April 21, 2021 which is hereby incorporated by reference in its entirety.

[0002] This patent application is related to US Pat. App. Pub. No. US 2019/0176403 Al, filed on December 4, 20218 and entitled “Method And Apparatus For Surface Finishing And Support Material Removal (Deci Duo) ”, the entire disclosure of which is hereby incorporated by reference.

FIELD OF THE DISCLOSURE

[0003] The present invention relates generally to a system and method that provides an improved way to manufacture parts using additive manufacturing processes that facilitates surface finishing including smoothing of the parts.

BACKGROUND OF THE INVENTION

[0004] Additive manufacturing processes, including three dimensional ("3D") printing, selective laser sintering ("SLS"), stereolithography ("SLA"), fused deposition modeling ("FDM"), material jetting ("MJ"), electron beam ("e-beam"), etc., have revolutionized the design and manufacturing industries. These processes are used to make parts from a variety of build materials, including metals/alloys, ceramics and polymers (including plastics). Additive manufacturing allows for the production of parts with different sizes and geometries and even geometries which would not have been possible with traditional manufacturing techniques, such as casting, injection molding, or forging.

[0005] An issue that sometimes arises with some additive manufacturing processes is the need for smoothing a surface of the part made by the additive manufacturing process. Since additive manufacturing creates a part in discrete layers, the surface finish of a part may be rough or striated, because each printed layer may not line up precisely with an adjacent layer, thus leaving a striated surface. This striated surface may be incompatible with the use for which the part is intended thereby requiring that the surface of the part be smoothed after being printed but before it is used for its intended purpose.

[0006] A prior solution in the additive manufacturing industry has been to manually smooth the surface of the part. Depending on the type of part or its design, manually smoothing parts can be labor intensive, time-consuming, inconsistent, cost prohibitive, and potentially damaging to the part.

[0007] Another approach taken by some in the additive manufacturing industry is use of machines to perform surface finishing. However, these machines have generally had limited functionality and also often require ongoing operator involvement during use thus failing to eliminate the manual labor obstacle. Thus, there has been a long-felt need for a method and apparatus for automatically smoothing the surface of parts made using additive manufacturing techniques.

[0008] PostProcess Technologies, Inc. of Buffalo, NY has developed systems for finishing additively manufactured parts. These systems include software-controlled machines and specially-designed chemical formulations. A PostProcess® system for smoothing surfaces of additively manufactured parts is the DECI Duo™ system, described in US Pat. App. Pub. No. US 2019/0176403 Al. The systems described in US Pat. App. Pub. No. US 2019/0176403 Al, as well as other systems from PostProcess Technologies, Inc., provide improved solutions for finishing parts made by additively manufacturing. There exists room for further improvements.

SUMMARY OF THE INVENTION

[0009] The present invention comprises a system and method for additively manufacturing an object to facilitate smoothing a surface of the object. An evaluation is made whether positioning the object with a specific orientation in a finishing apparatus is desirable and if so, the object is printed with an alignment feature on a body of the object. After printing the object, the object is positioned in the finishing apparatus by using the alignment feature on the object to position the object in the finishing apparatus in a specific orientation, and then the finishing apparatus is operated to smooth a surface of object. After smoothing the surface of the object, the alignment feature may be detached if necessary.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] For a fuller understanding of the nature and objects of the invention, reference should be made to the accompanying drawings and description.

[0011] FIG. l is a diagram showing a portion of an apparatus for finishing additively manufactured parts in which an embodiment of the present invention can be used.

[0012] FIG. 2 is a perspective view of a turntable platform shown in FIG. 1. [0013] FIGS. 3A, 3B, and 3C are different perspective views of an additively manufactured part that can be finished in the apparatus of FIG. 1.

[0014] FIG. 4 is a perspective view of another additively manufactured part that can be finished in the apparatus of FIG. 1.

[0015] FIG. 5 is a perspective view of still another additively manufactured part that can be finished in the apparatus of FIG. 1.

[0016] FIGS. 6A, 6B, and 6C are perspective views of the additively manufactured part shown in FIGS. 3A, 3B, and 3C with the addition of a detachable stalk in accordance with an embodiment of the invention.

[0017] FIG. 7 is a perspective view of the additively manufactured part shown in FIG. 4 with the addition of a detachable stalk in accordance with an embodiment of the invention. [0018] FIG. 8 is a perspective view of the additively manufactured part shown in FIG. 5 with the addition of a detachable stalk in accordance with an embodiment of the invention. [0019] FIG. 9 is a perspective view of a mounting fixture used in the apparatus of FIG. 1 according to an embodiment of the invention.

[0020] FIG. 10 is a view of an end of a detachable stalk.

[0021] FIG. 11 is a view of an end of another detachable stalk with a profile different than the profile of the detachable stalk in FIG. 10.

[0022] FIG. 12 is a view of an end of yet another detachable stalk with a profile different than the profiles of the detachable stalks in FIGS. 10 and 11.

[0023] FIG. 13 is block diagram showing components of an alignment feature design system in accordance with an embodiment of the invention.

[0024] FIG. 14 is a flow chart of steps in a process to additively manufacture a part and finish the part in accordance with an embodiment of the invention.

[0025] FIG. 15 is a perspective view of another embodiment of the invention.

[0026] FIG. 16 is a diagram of another alternative embodiment of the invention.

[0027] FIG. 17 is a flow chart of a process performed by the embodiment of FIG. 16. DETAILED DESCRIPTION OF THE INVENTION

[0028] Embodiments of the present invention are used in connection with apparatuses like those disclosed in US Pat. App. Pub. No. US 2019/0176403 Al. An example of such an apparatus is the PostProcess® DECI Duo system for surface finishing parts made by additive manufacturing processes. Embodiments of the present invention can be used in other systems and apparatuses as well, as described below. [0029] FIG. 1 shows a diagram of a portion of an apparatus 10 for surface finishing additively manufacture parts. The apparatus 10, the portion of which is shown in FIG.1, is similar or identical to the apparatus 10 disclosed in US Pat. App. Pub. No. US 2019/0176403 Al.

[0030] The apparatus 10 uses a fluid formulation 7 to smooth a surface of one or more additively manufactured parts 19. The fluid formulation 7 is composed of a liquid that has solid media particles suspended, entrained, or carried therein. The composition of the liquid and the size, shape, and composition of the solid media particles are selected to facilitate abrasion to smooth surfaces of additively manufactured parts. Suitable formulations are disclosed in US Pat. App. Pub. No. US 2019/0322898 Al filed April 22, 2019 and PCT App. No. PCT/US2020/038482, filed June 18, 2020, the entire disclosures of which are incorporated by reference herein. Suitable formulations include the following consumable products from PostProcess Technologies, Inc.: PLM-001-DUO detergent, MTL-001-DUO, AS-SS, AS-ALO, and SS-SS suspended solids

[0031] The apparatus 10 includes a spraying chamber 25. Located in the spraying chamber 25 is a platform 22, which, in one embodiment, is a turntable. A plurality of spray nozzles are located in the spraying chamber 25, including one or more side nozzles 28A and one or more upper nozzles 28B. The side nozzles 28 A are located horizontally adjacent an upper side of the turntable platform 22. The upper nozzles 28B are located vertically above the upper side of the turntable platform 22. The side nozzles 28A are oriented horizontally to spray at parts located on the upper side of the turntable platform 22. The upper nozzles 28B are oriented vertically downward toward the upper side of the turntable platform 22 to spray at parts located on the upper side of the turntable platform 22.

[0032] As shown in FIG. 2, the turntable platform 22 has openings 23 so that the fluid formulation 7 sprayed from the side nozzles 28A and upper nozzles 28B can pass through the turntable platform 22 and not collect on a top surface of the turntable platform 22.

[0033] Referring again to FIG. 1, located below the turntable platform 22 is a tank 31, open at its upper side 34. After being sprayed at the parts 19 on the turntable platform 22, the fluid formulation 7 sprayed at the parts 19 passes through the openings 23 in the turntable platform 22 and falls into the tank 31.

[0034] A pump 37 is connected to the tank 31 by a suitable conduit. The pump 37 draws the fluid formulation 7 from the tank 31 and then pumps the fluid formulation 7 through conduits 43 to the side nozzles 28A and upper nozzles 28B, which, together with forced air (i.e. "compressed air"), cause the fluid formulation 7 to spray out of the side nozzles 28A and upper nozzles 28B at the parts 19 located on the turntable platform. After being sprayed at the parts 19, the fluid formulation 7 then collects back into the tank 31 from which it is pumped back to the nozzles 28A and 28B again.

[0035] The positions of the side nozzles 28A and upper nozzles 28B relative to the turntable platform 22 are adjustable so that the side nozzles 28A and upper nozzles 28B can be located nearer to or farther away from parts 19 located on the turntable platform 22. In addition, one or more actuators (not shown) are operatively connected to the side nozzles 28A and upper nozzles 28B. The actuators provide for movement of the side nozzles 28A and upper nozzles 28B during operation, including oscillation of position relative to the turntable platform 22 (back-and-forth, side-to-side, upward-and-downward) or oscillation of orientation (sweeping angle back-and-forth).

[0036] The turntable platform 22 is connected to an actuator (not shown) that provides for optionally rotating the turntable platform 22.

[0037] US Pat. App. Pub. No. US 2019/0176403 A1 includes further details and information about the apparatus 10 and its components.

[0038] Operation of the smoothing apparatus. The apparatus 10 is operated to finish an additively manufactured part, and more particularly to smooth one or more surfaces of an additively manufactured part. In operation, one or more parts 19 are located on the turntable platform 22. The turntable platform 22 includes features so that one or more parts 19 to be finished can be secured to the turntable platform 22. These features for securing may include T-nuts, bolts, ties, clamps, etc. Alternatively, the parts 19 may be placed in a basket structure which is then secured to the turntable platform 22 so that the parts 19 may tumble inside the basket structure.

[0039] US Pat. App. Pub. No. US 2019/0176403 A1 includes additional information about the operation of the apparatus 10.

[0040] As mentioned above, additive manufacturing enables production of parts having complex geometries. Depending on the orientation of the part during the process of printing, one or more surfaces of the part may be striated. Striae occur on some surfaces of an additively manufactured part as a result of the printing process. Further, depending on the orientation of the part during the process of printing, some surfaces of the part may be more striated than other surfaces. Still further, depending on the use to which the part will be put, it may be necessary to smooth some or all striated surfaces of the part to the same or different specific levels of smoothness.

[0041] FIGS. 3A, 3B, 3C, 4 and 5 show examples of additively manufactured parts having complex geometries. FIGS. 3A, 3B, and 3C are perspective views of a part 100 having a complex geometry. The part 100 in FIGS. 3A, 3B, and 3C has multiple oblique surfaces, multiple curved surfaces, and internal passages. FIG. 4 is a perspective view of another additively manufactured part 110 having multiple oblique surfaces, multiple curved surfaces, and internal passages. FIG. 5 is a perspective view of yet another additively manufactured part 120 having multiple oblique surfaces, multiple curved surfaces, and internal passages. The parts 100, 110, 120 may have a combination of striated surfaces that require smoothing, striated surfaces that do not require smoothing, and/or surfaces that are not striated.

[0042] When using the apparatus 10 to smooth one or more surfaces of a part, it may be preferable to take into account factors such as which surfaces of the part have striae, which surfaces of the part require smoothing, and what degree of smoothness is required. These factors help determine an appropriate orientation of the part when positioning the part on the turntable platform 22. For example, it may be preferable to orient a striated surface of an additively manufactured part toward either the side nozzles 28 A or upper nozzles 28B. In another example, if an internal passage of an additively manufactured part requires smoothing, it may be preferable to orient an opening to the internal passage toward the side nozzles 28 A or the upper nozzles 28B. Positioning an additively manufactured part in the apparatus 10 with the proper orientation provides that those surfaces of an additively manufactured part that require smoothing are smoothed to a desired level of smoothness in an efficient manner. Further, positioning an additively manufactured part in the apparatus 10 with the proper orientation is more efficient, cost-effective, flexible and easier to implement than modifying the apparatus.

[0043] In some circumstances, it may be difficult to know which surfaces of the part have striae, which surfaces of the part require smoothing, and how smooth a surface is needed. [0044] To facilitate positioning of an additively manufactured part with proper orientation in the apparatus 10, a present embodiment provides for adding an alignment feature to the additively manufactured part. In one embodiment, the alignment feature is a stalk, stem or other extension or protrusion on the body of the object. In one embodiment, the stalk is detachable so that after the additively manufactured part is finished to a desired level of smoothness, the stalk can be removed from the additively manufactured part. (In an alternative embodiment, described below, the stalk is not detachable and is not removed after the part is smoothed.) In a present embodiment, the stalk is added to, or integrated with, the additively manufactured part during the additive manufacturing of the part. That is, the additively manufactured part is printed with the stalk physically connected to and extending from the body of the part. The stalk is printed with the part by the additive manufacturing printer. One way to cause the additive manufacturing printer to add a stalk and print the stalk connected to the additively manufacture part is to modify the print file used by the printer to add the stalk to the body of the part to be printed so that the stalk is printed at the same time as the part during and as part of the printing process.

[0045] In one embodiment, the stalk is added to the part being printed at a location, and in an orientation and size, on the part that facilitates positioning the part with a desired orientation in the finishing apparatus 10. This takes into account which surfaces of the part will have striae when printed and which striated surfaces require smoothing. This embodiment also takes into account how the stalk can be used to position the part with a desired orientation in the finishing apparatus 10 taking into account the design and configuration of the finishing apparatus, e.g., the location and orientation of the spray nozzles.

[0046] If more than one surface of an additively manufactured part has striae that require smoothing, the additively manufactured part can be printed with multiple stalks at different locations on the body thereof.

[0047] FIGS. 6A, 6B, 6C, 7, and 8 show additively manufactured parts printed with detachable stalks in accordance with an embodiment of the present invention. FIGS. 6A, 6B, and 6C show the additively manufactured part 100 from FIGS. 3A, 3B, and 3C with a detachable stalk 102 connected to and extending from the body thereof. FIG. 7 shows the additively manufactured part 110 from FIG. 4 with a detachable stalk 112 connected to and extending from the body thereof. FIG. 8 shows the additively manufactured part 120 from FIG. 5 with two detachable stalks 122 and 124 connected to and extending from different locations on the body thereof.

[0048] As explained above, adding a detachable stalk to a body of an additively manufactured part can facilitate positioning the part with a desired orientation in an apparatus used for smoothing surfaces of the part. In a present embodiment, positioning the part with a detachable stalk with a desired orientation in the smoothing apparatus is facilitated by using a mounting fixture. FIG. 9 shows a mounting fixture 50. The mounting fixture 50 is sized and adapted to be affixed to the turntable platform 22 (in FIG. 1) by suitable means, such as clamps, thumbscrews, lock nuts, a friction fitting, compression fittings, or other devices. The mounting fixture 50 includes one or more openings or slots 52, 54, and 56. Each of the openings 52, 54, and 56 is sized and adapted to receive therein a stalk like the detachable stalks 102, 112, 122, 124 on the additively manufactured parts 100, 110, 120.

[0049] To facilitate proper orientation and to provide for different orientations for different types, sizes, and shapes of parts, the detachable stalks that are added to the additively manufactured parts are printed with specific cross sectional profiles or “key” shapes. Different cross sectional profiles can be selected and used to provide for different orientations of parts in the finishing apparatus 10. The profile of the stalk matches the shape of a corresponding opening the mounting fixture 50. FIG. 10 shows an end 103 of the detachable stalk 102 opposite the body of the additively manufactured part 100 shown in FIGS. 6 A, 6B, and 6C. The end 103 of the detachable stalk 102 has a cross sectional profile that fits into the corresponding slot 56 in the mounting fixture 50 shown in FIG. 9. FIG. 11 shows an end 113 of the detachable stalk 112 opposite the body of the additively manufactured part 110 shown in FIG. 7. The end 113 of the detachable stalk 112 has a cross sectional profile that fits into the corresponding slot 52 in the mounting fixture 50 shown in FIG. 9. FIG. 12 shows an end 123 of the detachable stalk 122 opposite the body of the additively manufactured part 120 shown in FIG. 8. The end 123 of the detachable stalk 122 has a profile that fits into the corresponding slot 54 in the mounting fixture 50 shown in FIG. 9. FIGS. 10, 11, and 12 show three examples of profiles of detachable stalks and various other shapes and sizes of profiles may be developed and used with corresponding profiles of openings in the mounting fixture. In one embodiment, each opening is designed to receive only a specific stalk profile in a specific orientation to reduce or minimize operator error. [0050] As explained above, the design of the size and location of the detachable stalk on the body of an additively manufactured part is made to facilitate positioning the additively manufactured part with a desired orientation in the smoothing apparatus 10. The design process takes into account which surfaces of the part require smoothing. The design process can be done manually, i.e., by the person who designs the part using knowledge and information about which surface(s) of the part will require smoothing after printing. Alternatively, the design process can be performed by an automated system that analyzes a design file used for printing the additively manufactured object, obtains additional information, and then automatically prepares a new design file for printing the object that includes the detachable stalk on the appropriate surface thereof.

[0051] FIG. 13 is a block diagram of an alignment feature design system 82 for modifying a print design file to add an alignment feature, such as a detachable stalk, if appropriate. The alignment feature design system 82 shown in FIG. 13 is a software program run on an appropriate computer hardware platform, such as a personal computer, digital controller, network server, etc., or alternatively, the stalk design system 82 can be incorporated as part of a 3D printer or an apparatus that finishes parts made a 3D printer (such as the apparatus 10 in FIG. 1). The alignment feature design system 82 receives the original print design file 84. The alignment feature design system 82 may receive the original print design file 84 from the operator, from a 3D printer 86 or from another source. The original print design file contains information about the size, geometry, wall thickness, internal passages, surfaces, angles, etc., of the part to be printed. The alignment feature design system 82 may also receive additional data, files, parameters or inputs, including information about the type of 3D printer being used in making the part, information about the material used in making the part, information about the type of finishing apparatus being used, information about the chemicals (e.g., the detergent) being used in the finishing apparatus, as well as other information. This additional information may be obtained from an operator, the 3D printer 86, the finishing apparatus 10, or other sources.

[0052] After receiving this information, the alignment feature design system 82 evaluates whether the part being manufactured has one or more surfaces that will require smoothing and, if so, whether it would be appropriate to add an alignment feature, such as a detachable stalk, to position the part with a specific orientation in the finishing apparatus to be used to smooth the striated surface(s). In determining whether an alignment feature is appropriate, the alignment feature design system 82 takes into account factors mentioned above, such as the size and geometry of the part, the kind of 3D printer being used to make the part, the material from which the part is being printed, the expected striae on surfaces of the part, the kind of finishing apparatus to be used, the chemicals used in the finishing apparatus to smooth the part, as well as other factors. If the alignment feature design system 82 determines that it is appropriate to add an alignment feature, such as a detachable stalk, to the part, the alignment feature design system 82 determines the size and geometry of the alignment feature and the appropriate location and orientation on the part to which to add the alignment feature so that the part has a desired orientation in the finishing apparatus. Then, the alignment feature design system 82 modifies the original print design file 84 to produce a modified print design file 85 that include the alignment feature.

[0053] In one alternative embodiment, the alignment feature design system 82 also accesses a design database 98. The design database 98 contains information from previous evaluations of parts requiring smoothing. The information in the design database 98 can be used for facilitating the evaluation of the suitability of modifying a part to include an alignment feature . The design database 98 may be located locally (e.g., physically proximate with the printer and/or finishing apparatus) or remotely (e.g., accessible over a network). The design database 98 may be associated with just a single printer and/or finishing apparatus or may be shared with multiple printers and/or finishing apparatuses, either locally or remotely. The information in the design database 98 includes and is searchable by part size and geometry, materials, hardware (3D printer, finisher), chemicals (e.g., detergents), etc. After the alignment feature design system 82 evaluates the suitability of modifying the print design file to include an alignment feature, such as a detachable stalk, and forms a modified print design file, the information about the evaluation and modified file is stored in the design database 98 for use in evaluating print design files in the future.

[0054] FIG. 14 is a flowchart showing an embodiment of a process 200 for additively manufacturing a part with one or more alignment features, such as a detachable stalk, in accordance with the present invention. (The first three steps of the process 200, i.e., Steps 204, 206 and 208, may use the alignment feature design system 82 in FIG. 13.) In a first step (Step 204), the print design file 84 is received. Next, the geometry of the print design file 84 is examined and evaluated to determine whether it is desirable to position the printed part with a specific orientation during finishing and if so whether to add one or more alignment features, such as a detachable stalk (Step 206). If it is determined that it is not desirable to position the printed part with a specific orientation during finishing or if it is not appropriate to add one or more alignment features, the part is printed and finished with the process disclosed in US Pat. App. Pub. No. 20190176403. However, if it is determined that it is desirable to position the printed part with a specific orientation during finishing and to add one or more alignment features, the modified print design file 85 is produced (Step 208). In this embodiment, the alignment feature is a detachable stalk. The part is printed with a 3D printer using the modified print design file 85 (Step 210). Next, the part is placed in the chamber of the finishing apparatus 10 by inserting the detachable stalk into the corresponding matching opening in the mounting fixture 50 (Step 216). The part is sprayed in the finishing apparatus to smooth surfaces of the part (Step 218). After the surfaces of the part have been smoothed, if the part has an additional surface to be smoothed and has an additional detachable stalk to facilitate positioning the part in the apparatus with another desired orientation, the part is reoriented in the finishing apparatus by inserting another of the stalks into the mounting fixture (Steps 220, 222, and 216) and then the part is sprayed again (Step 218). These steps (Steps 220, 222, 216, and 218) are repeated until the part is sprayed in all orientations for which detachable stalks were added. Then, the one or more stalks are detached (Step 224). The detachable stalk(s) can be removed manually, for example by snapping off the stalk by hand, or the detachable stalk(s) can be removed by an automated process, such as by using a robotic arm. If necessary, the location on the part where the detachable stalk was connected may be smoothed, either manually or by using an automated process such as by application of a spray in the finishing apparatus 10. The part is removed from the finishing apparatus 10 (Step 226) and the process is done (Step 228).

Alternatives embodiments

[0055] In the embodiments described above, it was stated that the disclosed invention can be used in systems for finishing additively manufactured parts like the systems disclosed in US Pat. App. Pub. No. US 2019/0176403 Al. The disclosed invention can be used in other systems for finishing parts in which it is desired to position a part with a specific orientation. Examples of such systems include those disclosed in US Pat. No. 10,737,440, US Pub. Nos. US 2019/0022931 Al, and US 2019/0202126 Al, the entire disclosures of which are incorporated by reference herein.

[0056] In some of the embodiments disclosed above, the stalk was described as being detachable. In an alternative embodiment, the stalk is not detachable. According to this alternative, when the design of the object is being evaluated for whether adding a stalk would facilitate positioning the object with a desired orientation in a finishing apparatus, an evaluation is also made whether a non-detachable stalk can be added to the object without detracting from the ultimate intended purpose of the object. If the ultimate purpose of the object would not be affected by adding a stalk to the object to facilitate positioning in a desired orientation in a finishing apparatus, the print file is modified to add a non-detachable stalk. An advantage of this embodiment is that the need to remove the stalk and possibly smooth the location on the body of the object where the stalk was attached is eliminated. [0057] In another alternative embodiment, a detachable stalk can be designed that has a single stem at the end that attaches to the additively manufactured part and multiple branches extending from the single stem that have profiles that match one or more openings in the mounting fixture. This embodiment has the advantage that a single stalk can provide for multiple orientations of the part during the finishing operation.

[0058] The detachable stalk can have different shapes, including straight, curved, bent, angled, or tapered. The shape of the detachable stalk relates to providing a desired orientation of the additively manufactured part in the finishing apparatus. In further alternatives, the detachable stalk can be hollow or may be designed with creases or perforations to facilitate removal after the finishing process.

[0059] In another alternative embodiment, when a determination is made to add a stalk to an additively manufactured part to facilitate positioning during finishing, instead of modifying the original design file, the detachable stalk is added to the design in a temporary or intermediate file, or in the printer file or data stored in the printer operating memory.

[0060] FIG. 15 shows another alternative embodiment. In the embodiment shown in FIG. 15, the design of an additively manufactured object is evaluated to determine whether adding an alignment feature would facilitate positioning the object with a desired orientation in a finishing apparatus. If a determination is made that it is appropriate to add an alignment feature to the object, an appropriate size and geometry of the alignment feature is determined. In this embodiment, instead of modifying the print design file to include a detachable stalk, the print design file is modified to include a mounting slot, cavity or receptacle at a location on the body of the object. FIG. 15 shows an additively manufactured object 300 with a mounting slot 302 formed therein. The mounting slot 302 on the body of the object 300 has a size and profile to receive therein a separate mounting stalk 304. The separate mounting stalk 304 has a size and profile that fits into the slot 302 on the object 300. The separate mounting stalk 304 also has a size and profile that fits into an opening on a mounting fixture that can be located, or is already affixed or present, in a finishing apparatus, such as one of the openings 52, 54 or 56 in the mounting fixture 50 shown in FIG. 9. The size and profile of the end of the mounting stalk that fits into the mounting slot in the object may be the same as the size and profile of the other end of the mounting stalk that fits into the mounting fixture, or they may be different. After the object with the mounting slot is printed, the mounting stalk 304 is inserted into the mounting slot 302 in the object 300, as indicated by the arrow 306 in FIG.

15. Then, the object with the separate mounting stalk inserted therein is installed in a finishing apparatus by inserting the mounting stalk into the appropriate opening in the mounting fixture, such as the fixture 50 in FIG. 9. After the surface of the object is smoothed, the separate mounting stalk is removed from the mounting slot in the object. The mounting slot in the object may be filled in or may be left open. This embodiment has the advantage that it may be relatively easier to remove the separate mounting stalk from a mounting slot on an object than a stalk that has been printed already attached to the object. Also, this embodiment has the advantage that it may be easier to smooth the location on the object where the stalk was inserted. In this embodiment, the separate mounting stalk may be printed with the object, but as a separate piece. Alternatively, the separate mounting stalk may be constructed separately. The separate mounting stalk may be reused for use smoothing different additively manufactured objects, or may be reused for use smoothing different surfaces of the same additively manufactured object.

[0061] FIG. 16 shows another alternative embodiment. FIG. 16 shows a portion of an apparatus 410 for surface finishing additively manufacture parts. The apparatus 410 in FIG. 16 is similar to the apparatus 10 in FIG. 1. The apparatus 410 includes a spraying chamber 425 in which is located a turntable platform 422 upon which a mounting fixture 450 is attached. Parts 419 to be smoothed are mounted by detachable stalks onto the mounting fixture 450. A pump 437 pumps a fluid formulation 407 from a tank 431 located below the turntable platform 422 to side nozzles 428 A and upper nozzles 428B to spray at the parts 419. [0062] The apparatus 410 includes one or more sensors 440. The sensors 440 are operative to sense the parts 419 on the turntable platform 422. More specifically, the sensors 440 are adapted to sense (or measure) properties indicative of smoothing of the parts 419. Thus, the sensors 440 provide for real time feedback of the smoothing process. The sensors 440 may include suitable devices, such as an optical profilometer, a lidar system, a CT scanner, cameras, ultrasound, or radar. The outputs from the sensors 440 are provided to a controller 448 of the system 410. Programming 452 on the controller 448 uses the information in the outputs from the sensors 440 to analyze (i.e., measure) the smoothness of the parts during the smoothing operation. Based on these measurements, the programming 452 automatically determines whether to modify the smoothing process (e.g., increase or decrease spray intensity and/or direction), reorient the parts, or stop the spraying when the smoothing process is complete, i.e., when the parts are at a desired level of smoothness. [0063] FIG. 17 is a flowchart that shows an embodiment of a process 460 performed by the apparatus 410 in FIG. 16. After the parts 419 are installed in the mounting fixture 450 on the turntable platform 422 (Step 462) and an appropriate set of operating parameters are selected (Step 464), the apparatus 410 is operated (e.g., pump 437 is engaged) to spray the fluid formulation 407 at the parts 419 (Step 466). The sensors 440 are operated to sense the parts 419 and provide outputs to the controller 448 (Step 468). The sensors 440 may operate continuously or intermittently. The programming 452 on the controller 448 analyzes the information from the sensors 440 (Step 470). This step may involve image recognition as well as other technologies. The programming 452 determines the smoothness of the parts being sprayed, but also may perform other functions including determining whether to increase or decrease spray intensity and if so to what degree, determining whether to change spray nozzle orientation and if so in what direction(s), determining whether to reorient the parts and if so how, as well as other functions (Step 472). If it is determined that modification of the process is needed, the process is modified and spraying continues (Steps 472, 474, and 466). If no modification is determined to be needed, it is determined whether further smoothing is needed and if so, the spraying continues (Steps 476 and 466). If it is determined that the parts are at a desired level of smoothness, the parts are removed from the apparatus (Step 478), the detachable stalks removed (Step 480) and the process ends (Step 482). (The process 460 in FIG. 17 may include additional steps including some or all the steps in the process 200 in FIG. 14.)

[0064] The process 460 in FIG. 17 provides several advantages. One advantage is that smoothing operation proceeds automatically, i.e., reducing labor-intensive tasks. The process also provides for efficiency and consistency.

[0065] A system like the one described herein can be used in equipment or systems that finish or otherwise process parts produced by other than additive manufacturing processes. For example, a system like the one described herein can be used in systems or equipment that finish or otherwise process parts produced by traditional manufacturing processes or other kinds of non-traditional manufacturing processes.

[0066] In embodiments described above, an alignment feature was disclosed as being a stalk or a slot into which a stalk could be inserted. In alternative embodiments, the alignment feature may have other types of construction. The alignment feature may be formed as a stub, a stem, an extension, a protrusion, a hook, a notch, perforations, or combinations thereof. In further alternative embodiments, the detachable stalk may be formed as a single piece or multiple pieces.

[0067] In the foregoing description, example embodiments are described. The specification and drawings are accordingly to be regarded in an illustrative rather than a restrictive sense.

[0068] It will be appreciated that various aspects of the above-disclosed invention and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, and/or improvements therein may be subsequently made by those skilled in the art, and those alternatives, modifications, variations, and/or improvements are intended to be encompassed by the following claims.

[0069] Although the present invention has been described with respect to one or more particular embodiments, it will be understood that other embodiments of the present invention may be made without departing from the spirit and scope of the present invention. Hence, the present invention is deemed limited only by the appended claims and the reasonable interpretation thereof.

Claims

CLAIMS:

1. A method of printing an object with an additive manufacturing process comprising: evaluating a print design file that defines physical properties of an object to be printed with the additive manufacturing process to determine whether the object defined by the printed design file includes a surface to be smoothed in a finishing apparatus; determining a desired orientation of the object in the finishing apparatus to smooth the surface; and modifying the print design file to include an alignment feature on the object to facilitate mounting the object in the finishing apparatus with the desired orientation.

2. The method of Claim 1 further comprising: with the additive manufacturing process, printing the object with the alignment feature.

3. The method of Claim 2 further comprising: positioning the object in the finishing apparatus with the desired orientation using the alignment feature.

4. The method of Claim 3 wherein the alignment feature is a detachable stalk extending from the object, and wherein the step of positioning the object in the finishing apparatus further comprises mounting the detachable stalk into a slot in the finishing apparatus.

5. The method of Claim 4 wherein the detachable stalk has a profile that matches a profile of the slot.

6. The method of Claim 4 further comprising: after operating the finishing apparatus to smooth the surface, removing the detachable stalk from the object.

7. The method of Claim 6 wherein the detachable stalk is removed with an automated mechanism.

8. The method of Claim 7 further comprising: smoothing a location on the body of the object where the detachable stalk had been attached.

9. The method of Claim 3 wherein the alignment feature is a slot located in the object, and wherein the step of positioning the object in the finishing apparatus further comprises mounting the object on a stalk in the finishing apparatus.

10. The method of Claim 9 wherein the slot has a profile that matches a profile of the stalk.

11. The method of Claim 3 further comprising: operating the finishing apparatus to smooth the surface.

12. The method of Claim 11 further comprising: after starting the step of smoothing the surface of the object, sensing a smoothness of the surface of the object by use of a sensor associated with the finishing apparatus.

13. The method of Claim 11 wherein the finishing apparatus includes at least one nozzle that sprays a surface-smoothing formulation.

14. The method of Claim 13 wherein the surface- smoothing formulation comprises a liquid having solid media entrained therein.

15. The method of Claim 1 wherein the step of determining a desired orientation of the object in the finishing apparatus further comprises: determining multiple desired orientations of the object in the finishing apparatus; and wherein the step of modifying the print design file further comprises: modifying the print design file to include multiple alignment features on the object to facilitate mounting the object in the finishing apparatus with the multiple desired orientations.

16. An object manufactured using the modified print design file of Claim 1.

17. The object of Claim 16 wherein the alignment feature and a body of the object are composed of the same material.

18. A system for manufacturing an object with an additive manufacturing process comprising: an alignment feature design component that evaluates a print file to determine whether the object has a surface suitable for being aligned with a specific orientation in a finishing apparatus and if so, modifies the print file to include an alignment feature attached on the object at a location so that the alignment feature can be used to position the object in the finishing apparatus with the specific orientation; and an additive manufacturing printer that receives the modified print file from the alignment feature design component and prints the object with the alignment feature.

19. The system of Claim 18 further comprising: a finishing apparatus that receives the object with the alignment feature from the additive manufacturing printer, has the object with the alignment feature mounted therein, and smooths the surface of the object.

20. The system of Claim 19 wherein the alignment feature is a detachable stalk and wherein the finishing apparatus has a mechanism that removes the detachable stalk mechanically.

21. The system of Claim 19 wherein the finishing apparatus includes at least one sensor that detects properties of the object during a finishing process and a controller that receives an output from the at least one sensor and modifies or stops the finishing process based on said output.

22. The system of Claim 18 wherein the alignment feature design component evaluates suitability to include the alignment feature based on at least one of: a size and geometry of the object, a type of 3D printer used to make the object, a material from which the object is printed, a kind of finishing apparatus being to smooth a surface of the object, and one or more chemicals used in the finishing apparatus.

23. The system of Claim 18 wherein the alignment feature design component determines a size and geometry of the alignment feature.

24. The system of Claim 18 wherein the alignment feature design component accesses an alignment feature design database that contains information from previous evaluations of objects with surfaces to be smoothed for facilitating evaluation of suitability of modifying the print file for the object to include an alignment feature