Method for additively manufacturing an article with a groove

Abstract

A method is disclosed for additively manufacturing an article comprising a groove. The method includes obtaining (202) a model of an article to be manufactured, the article comprising a groove, the groove comprising two sides with a gap between them. The method further includes adapting (204) the model by adding supports connecting the sides of the groove, and additively manufacturing (206) the article based on the adapted model. The method further includes removing (207) the loose powder from the groove, sintering (208) the additively manufactured article, and removing (210) the supports, thereby obtaining the manufactured article.

Description

[Technical field]

[0001] The present disclosure relates generally to methods and systems for additive manufacturing of articles comprising grooves, particularly using binder jetting techniques. [Background technology]

[0002] Additive manufacturing, also known as 3D printing, generally involves manufacturing or printing one layer at a time using specialized systems. In particular, a layer of powdered material can be deposited onto a work surface in a build chamber and then bonded with another layer of the same or different material. Additive manufacturing can be used to produce articles from computer-aided design models using techniques such as binder jetting.

[0003] Additive manufacturing steps are performed to compact and bond the powder composition, resulting in a green body. The green body is then subjected to sintering, where heat and / or pressure are applied to the green body. During the sintering process, powder particles fuse together, resulting in densification, and potentially adversely affecting the resulting article with shrinkage and / or deformation.

[0004] One case where such deformation is particularly relevant is where the article being manufactured includes a groove, which, if excessively deformed, may impair the functionality of the article.

[0005] Today, the way to deal with the problem of deformation occurring during sintering of green bodies is to compensate for the deformation beforehand, for example by modifying the dimensions of the article before it is additively manufactured. However, this is very difficult and requires very detailed knowledge of exactly how and to what extent the article will deform.

[0006] It would be beneficial to provide a better method of additively manufacturing articles with grooves such that reduced deformation occurs during sintering.

[0007] Thus, a need exists for improvements when using additive manufacturing techniques to produce articles with grooves. Summary of the Invention

[0008] It is the thesis of the present invention to address at least some of the problems and issues outlined above. The thesis of an embodiment of the present invention is to provide a method for manufacturing an article with grooves such that deformation during sintering, particularly deformation of the grooves, is reduced.

[0009] According to one aspect, a method for manufacturing an article comprising a groove is provided. The method includes obtaining a model of an article to be manufactured, the article comprising a groove, the groove comprising two sides with a gap therebetween. The method further includes adapting the model by adding supports connecting the sides of the groove, additively manufacturing the article based on the adapted model, and removing the loose powder from the groove. The method further includes sintering the additively manufactured article and removing the supports, thereby obtaining the manufactured article.

[0010] According to another aspect, an additive manufacturing system is provided that operates to additively manufacture an article comprising a groove. The additive manufacturing system comprises an additive manufacturing device, a processing circuit, and a memory including instructions executable by the processing circuit. The additive manufacturing system operates to obtain a model of an article to be manufactured, the article comprising a groove, the groove comprising two sides with a gap therebetween, and to adapt the model by adding supports connecting the sides of the groove. The additive manufacturing system is further operative to additively manufacture the article based on the adapted model and to remove loose powder from the groove. The additive manufacturing system is further operative to sinter the additively manufactured article and remove the supports, thereby obtaining a manufactured article.

[0011] According to other aspects, there is also provided a computer program and a carrier, the details of which are set out in the claims and the detailed description.

[0012] Further possible features and advantages of this solution will become apparent from the detailed description below.

[0013] The solution will now be explained in more detail by means of exemplary embodiments and with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0014] [Figure 1] 1 shows an article comprising a support according to different embodiments; [Diagram 2] 1 shows an article comprising a support according to different embodiments; [Diagram 3] 1 shows an article comprising a support according to different embodiments; [Figure 4] 1 shows an article comprising a support according to different embodiments; [Diagram 5] 1 shows an article comprising a support according to different embodiments; [Figure 6] 1 shows an article comprising a support according to different embodiments; [Figure 7] 1 is a flow chart of a method for manufacturing an article according to one embodiment. [Figure 8] FIG. 1 illustrates a block schematic diagram of components of an additive manufacturing system according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Briefly, the present disclosure relates to a method for manufacturing an article with a groove using additive manufacturing techniques. The method includes obtaining a model of the article with a groove and adapting the model by adding supports connecting sides of the groove, thereby obtaining an adapted model with the supports as part of the article. The method further includes additively manufacturing the article based on the adapted model, sintering the article, and then removing the supports, thereby obtaining a finished article without supports.

[0016] The present disclosure is based on the realization that an article with grooves can be better manufactured by adding supports connecting the sides of the grooves during additive manufacturing, sintering the article in the presence of the supports, and then removing the supports after the article has been sintered. The purpose of the supports is to reduce deformation of the article, especially of the grooves, and to achieve a more linear shrinkage during sintering. Preferably, the deformation should be as small as possible.

[0017] Deformation of the grooves during the sintering process typically requires subsequent machining of the grooves. Using the methods disclosed herein, it becomes possible, or at least easier, to additively manufacture articles having grooves in a manner that requires much less or no machining of the grooves themselves after sintering.

[0018] The support can be seen as a sintering support adapted to support an article during sintering, as opposed to a support used to support an article during an additive manufacturing process.

[0019] The methods and systems disclosed herein are suitable for use on virtually any article that includes grooves produced using additive manufacturing techniques, particularly when using binder jetting techniques.

[0020] Referring now to FIG. 1, a modified article comprising a support according to one embodiment is shown.

[0021] The modified article 100 comprises a groove 110 having a first side 112 and a second side 114 with a gap therebetween, and a floor portion 116. The modified article 100 further comprises a support 120 connecting the sides of the groove, the support 120 being intended to be removed after sintering of the article, and thus not intended to form part of the finished article.

[0022] The size and position of the support 120 can be adapted based on the article to be manufactured. When the width of the support is relatively small compared to the extension of the groove, as in the case of Figure 1, the support 120 is preferably positioned in the center of the groove 110, as in the case of Figure 1, in order to provide as much support as possible to the entire groove.

[0023] In some embodiments, such as that shown in FIG. 1, the support 120 is positioned above the groove so that the bottom of the support 120 is aligned with the top of the article 100 .

[0024] In some embodiments, such as that shown in FIG. 2, the support 120 is positioned inside the groove such that the top of the support 120 is aligned with the top of the article 100 .

[0025] In some embodiments, the support 120 is sized to cover as much of the groove as possible. Although it is desirable to cover the entire groove with the support, there will be loose powder in the groove that needs to be removed after the additive manufacturing process is complete. If the support covers the entire groove, the loose powder cannot be removed and an article without a groove will result after sintering has occurred. Therefore, the powder needs to be able to exit the groove at some locations.

[0026] 3 shows an embodiment having a support 120 with a hole 125 that covers substantially the entire groove (not shown in the figure since it is covered by the support 120) of the article 100. As can be seen, in the embodiment shown in FIG. 3, the hole 125 in the support 120, rather than the support 120 itself, is preferably positioned in the center of the groove in this embodiment.

[0027] 4 shows another embodiment comprising multiple supports 120 positioned along the groove 110. By positioning multiple relatively small supports, preferably relatively uniformly along the groove, a balance between structural support of the article and holes for removing powder can be achieved.

[0028] 5 and 6, there are shown embodiments in which the support 120 is adapted to provide a substantially flat surface of the conformable article in the plane in which the support extends. In some embodiments, the support is adapted to cover substantially all of the surface of the article in the same plane in which the support extends.

[0029] FIG. 5 shows an embodiment of the support of FIG. 1, in which the support 120 covers the entire top surface of the article 100.

[0030] FIG. 6 shows one embodiment of the support of FIG. 2, where the support covers the entire top surface as well as the front and back surfaces of the article 100.

[0031] One reason for the embodiments shown in Figures 5 and 6 is to provide a flat surface that is easy to machine after sintering has taken place and the support has been removed. Whether the embodiment of Figures 1 / 2 or 5 / 6 is used may depend on what technique is used to remove the support 120 after sintering.

[0032] In some embodiments, the grooves of the article extend at least partially in a vertical direction as seen during additive manufacturing of the article. In some embodiments, the grooves of the article extend in a direction offset from vertical by up to 45 degrees. In some embodiments, the grooves extend substantially only in a vertical direction.

[0033] The steps of a method for manufacturing an article comprising grooves according to one embodiment will now be described with reference to Figure 7. The method may be a computer-implemented method. The method may be performed by an additive manufacturing system.

[0034] The method includes obtaining 202 a model of the article with the groove. The model may be any type of model useful for the purpose, such as a CAD model. The model may be obtained in any applicable manner, for example, by using a CAD program to generate it or by obtaining a CAD model generated elsewhere.

[0035] The method further includes fitting 204 the model by adding supports connecting the sides of the grooves. The model is preferably fitted using a software program for working with such models, e.g., a CAD program. By having supports connecting the sides of the grooves, the grooves do not deform to the same extent as they would otherwise, since the supports counter and / or resist forces that act to deform the article during the sintering process.

[0036] The method further includes additively manufacturing 206 the article based on the adapted model. The additive manufacturing process includes using any relevant additive manufacturing technique where powders are bonded together to form the article. Because the article is additively manufactured based on the adapted model, the resulting green body is a adapted article with an added support.

[0037] The method further includes removing the loose powder from the grooves 207. The powder must be removed prior to sintering because it solidifies during the sintering process. In embodiments where the support includes holes, removing step 207 can include removing the loose powder through the holes in the support.

[0038] The method further includes sintering 208 the conformable article including the support. As previously mentioned, the support counteracts, at least to some extent, forces that cause deformation of the article, particularly the grooves, during sintering.

[0039] The method further comprises removing 210 the support, thus obtaining the finished article. Since the support is added during the additive manufacturing process, it must of course be removed after sintering to obtain the article, otherwise the obtained article will be a modified article with a support.

[0040] In some embodiments, the support may be used in an intermediate operation, such as turning or milling, before being removed. Thus, in some embodiments, the method may include using the support for an intermediate operation prior to removing 210 the support.

[0041] In some embodiments, the supports are positioned above the gaps of the grooves, and the supports can also be seen as above the grooves, rather than inside the grooves. Positioning the supports in this manner facilitates their removal after sintering has been performed. As will be appreciated, what is considered to be above the gaps / grooves will vary depending on which direction the grooves are facing. For example, in FIG. 4, both visible supports positioned on the sides of the article are also considered to be above the gaps.

[0042] In some embodiments, the support is positioned inside the gap, preferably as close as possible to the tops of the first and second sides. In some embodiments, the support is positioned inside the gap so as to connect the first and second sides into a continuous surface with no height difference, or at least a relatively small difference. In some embodiments,

[0043] In some embodiments, the support covers a majority of the grooves, the more the grooves are covered by the support the more it can resist or resist deformation during sintering.

[0044] However, there may be other reasons why one does not want to cover the entire groove, such as the need to remove loose powder from the groove before sintering. To this end, in some embodiments, the support may include a hole. In some such embodiments, the hole in the support is located approximately in the center of the support.

[0045] In some embodiments, the dimensions of the support are adapted based on the characteristics of the groove, the term groove characteristics including, for example, the size including the length, width and height of the groove, the orientation of the groove, the placement of the groove on the article, the material properties of the powder of the article, and similar information. As will be appreciated, larger grooves generally require larger supports than smaller grooves if they are to similarly reduce deformation during sintering.

[0046] In some embodiments, at least a portion of the gaps of the groove face upward, which may also be viewed as the groove facing upward. The direction "upward" is intended herein to indicate the upward direction of the article as it is positioned during sintering.

[0047] In some embodiments, the method can include positioning the article such that at least a portion of the groove gap faces upward during sintering 208. This can involve positioning the additively manufactured article after the additive manufacturing step 206 and before the sintering step 208 such that at least a portion of the groove gap faces upward.

[0048] In some embodiments, the support or at least one of the supports is positioned on top of the article during sintering with respect to how the article is positioned during sintering. Thus, in some embodiments, the method includes positioning the additively manufactured article such that the support is positioned on top of the article during sintering. This may involve positioning the additively manufactured article after additive manufacturing step 206 and before sintering step 208 such that the support is positioned on top of the article.

[0049] In some embodiments, the upward direction of the article during sintering is the same as the manufacturing direction of the article during the additive manufacturing step. In some embodiments, the method includes additively manufacturing the article during additive manufacturing step 206 such that at least a portion of the groove faces the manufacturing direction. In some embodiments, the method includes additively manufacturing the article during additive manufacturing step 206 such that the support is positioned at the top of the article, as viewed in the manufacturing direction.

[0050] In some embodiments, the support is positioned approximately in the center of the groove. This is particularly relevant in embodiments where the support covers a relatively small portion of the groove.

[0051] In some embodiments, fitting the model by adding supports 204 includes adding a number of supports, each connecting a side of the groove.

[0052] In some embodiments, the thickness of the support is 10% to 50% of the width of the groove, In some embodiments, the thickness of the support is 20% to 30% of the width of the groove.

[0053] In some embodiments, the holes 125 in the support have a diameter at least 3 times the diameter of the largest particle size of the powder, in some embodiments, the holes 125 have a diameter 5-10 times the diameter of the largest particle size of the powder, measured as the D90 of the powder.

[0054] In some embodiments, the width of the groove, i.e., the distance between the first side 112 of the groove and the second side 114 of the groove, is substantially the same throughout the groove. In some embodiments, the distance between the first side 112 of the groove and the second side 114 of the groove varies throughout the groove.

[0055] An example of an additive manufacturing system 600 according to one embodiment operative to perform methods according to the present disclosure will now be described.

[0056] The additive manufacturing system 600 comprises an additive manufacturing apparatus suitable for carrying out the method steps according to the present disclosure. Such an additive manufacturing apparatus comprises at least a powder bed, a means for supplying powder, and a means for fusing the powder together. As will be appreciated, the additive manufacturing apparatus may also comprise additional components. In some embodiments, the additive manufacturing apparatus may be a binder jetting printer, and the means for using the powder together is a means for dispensing binder to the powder bed. The additive manufacturing system may further comprise a means for sintering the article, and further comprise a means for removing the powder from the article.

[0057] Referring now to FIG. 8, a block schematic diagram of components of an additive manufacturing system 600 according to one embodiment is shown. The additive manufacturing system 600 comprises a processing circuit 603 and a memory 604. The processing circuit 603 may comprise one or more programmable processors, application specific integrated circuits, field programmable gate arrays, or combinations thereof (not shown) adapted to execute instructions. The memory includes instructions executable by said processing circuit, whereby the additive manufacturing system 600 operates to obtain a model of an article to be manufactured, the article comprising a groove, the groove comprising two sides having a gap therebetween. The additive manufacturing system 600 further operates to adapt the model by adding supports connecting the sides of the groove, additively manufacture the article based on the adapted model, and remove the loose powder from the groove. The additive manufacturing system 600 further operates to sinter the additively manufactured article and remove the supports, thereby obtaining the manufactured article.

[0058] The additive manufacturing system 600 performing the method may be a group of devices, and the functionality for performing the method is distributed across different physical or virtual devices of the system. In other words, the additive manufacturing system 600 may be a cloud solution, i.e., the additive manufacturing system 600 may be deployed as a cloud computing resource that may be distributed within the system.

[0059] According to one embodiment, additive manufacturing system 600 is further operative to perform any other of the method steps described herein.

[0060] According to other embodiments, the additive manufacturing system 600 may further comprise a communication unit 602, which may be considered to comprise conventional means for communicating with other parts of the additive manufacturing system. The instructions executable by the aforementioned processing circuitry 603 may for example be arranged as a computer program 605 stored in a memory 604. The processing circuitry 603 and the memory 604 may be arranged in a partial configuration 601. The partial configuration 601 may be a microprocessor and suitable software and storage, thus a programmable logic device, PLD, or other electronic component(s) / processing circuit(s) configured to perform the above-mentioned methods.

[0061] The computer program 605 may include computer readable code means which, when executed on the additive manufacturing system 600, causes the additive manufacturing system 600 to perform the steps described in any of the described embodiments of the additive manufacturing system 600. The computer program 605 may be carried by a computer program product connectable to the processing circuit 603. The computer program product may be the memory 604. The memory 604 may be realized, for example, as a RAM (Random-access memory), a ROM (Read-Only Memory), or an EEPROM (Electrical Erasable Programmable ROM). Furthermore, the computer program may be carried by a separate computer readable medium, such as a CD, a DVD, or a flash memory, from which the program may be downloaded to the memory 604. Alternatively, the computer program may be stored on a server or any other entity connected to the additive manufacturing system 600 accessible via the communication unit 602. The computer program may then be downloaded from the server to the memory 604.

[0062] Although the above description includes multiple specificities, these should not be construed as limiting the scope of the concepts described herein, but merely as providing illustrations of some exemplary embodiments of the concepts described herein. It will be understood that the scope of the concepts described herein fully encompasses other embodiments that may become apparent to one of ordinary skill in the art, and thus the scope of the concepts described herein should not be limited. Reference to an element in the singular does not mean "one and only one" unless expressly stated, but rather "one or more." All structural and functional equivalents to the elements of the above embodiments known to one of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed herein. Furthermore, a device or method need not address every problem sought to be solved by the concepts described herein to be encompassed herein. In the exemplary figures, dashed lines generally mean that the features within the dashed lines are optional.

Claims

1. 1. A method for manufacturing an article having a groove, comprising: Obtaining a model of an article to be manufactured (202), the article comprising a groove having two sides and a floor portion with a gap therebetween; Fitting the model by adding supports connecting the sides of the grooves (204); Additively manufacturing the article based on the adapted model (206); and Removing the loose powder from the grooves (207); Sintering the additively manufactured article (208); and removing 210 the support, thereby obtaining the manufactured article; A method comprising:

2. The method of claim 1 , wherein a support is positioned above the gap of the groove.

3. The method of claim 1 , wherein the support covers a majority of the groove.

4. The method of claim 1 , wherein the support comprises holes.

5. The method of claim 1 , wherein the dimensions of the support are adapted based on the characteristics of the groove.

6. 10. The method of claim 1, further comprising positioning the additively manufactured article such that at least a portion of the groove faces upward during sintering (208).

7. 10. The method of claim 1, further comprising positioning the additively manufactured article such that a support is positioned on top of the article during sintering (208).

8. The method of claim 1 , wherein the support is adapted to cover substantially the entire surface of the article in a plane in which the support extends.

9. The method of claim 1 comprising a plurality of supports each connecting a side of a groove.

10. The method of claim 1, wherein the thickness of the support is between 10% and 50% of the width of the groove.

11. The method of claim 1 , wherein the support is a sintering support adapted to support the article during sintering.

12. 1. An additive manufacturing system (600) operative to additively manufacture an article comprising a groove, the additive manufacturing system (600) comprising: An additive manufacturing device; A processing circuit (603); A memory (604), The memory (604) includes instructions executable by the processing circuitry (603) to cause the additive manufacturing system (600) to: Obtaining a model of an article to be manufactured, the article comprising a groove having two sides and a floor portion with a gap therebetween; Fitting the model by adding supports connecting the sides of the groove; Additively manufacturing an article based on the adapted model; Removing loose powder from the grooves; Sintering the additively manufactured article; and Removing the support, thereby obtaining the manufactured article. Works for, An additive manufacturing system (600).

13. 13. The additive manufacturing system (600) of claim 12, further operative to perform the steps of the method of any one of claims 2 to 11.

14. A computer program (605) comprising computer readable code means for execution on an additive manufacturing system (600), said computer readable code means, when executed on the additive manufacturing system (600), causing the additive manufacturing system (600) to perform the following steps: obtaining a model of an article to be manufactured, the article comprising a groove having two sides and a floor portion with a gap therebetween; Fitting the model by adding supports connecting the sides of the grooves; additively manufacturing the article based on the adapted model; removing the loose powder from the grooves; sintering the additively manufactured article; and Removing the support, thereby obtaining the manufactured article. A computer program (605) for causing the computer to execute the above steps.

15. A carrier comprising the computer program (605) of claim 14, which is one of an electronic signal, an optical signal, a radio signal or a computer readable storage medium.

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