Method and system for forming an article from a powder

Abstract

The present disclosure relates to a method and system for forming an article from a powder. A method of forming an article includes sequentially depositing a plurality of individual layers of a batch of powder over each other and melting the plurality of individual layers together to form a workpiece and excess powder. The method includes recovering excess powder from the workpiece to thereby form an article. Contemporaneously with the recovery, the method comprises: continuously analyzing the color of the excess powder to provide a color value; and distributing the excess powder according to the color value by at least one of: mixing the supply powder with at least a portion of the excess powder in a ratio of the supply powder to the excess powder to form a subsequent batch of powder; and quarantine isolating the excess powder from the supplied powder. A system for forming an article is also described.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a method and system for forming an article from powder. BACKGROUND

[0002] Additive manufacturing refers to the layer-by-layer formation of a three-dimensional object. In particular, layers of material can be deposited on top of one another under computer control to produce a three-dimensional object.

[0003] Powder bed fusion is a class of additive manufacturing that involves selectively fusing regions of a powder bed layer-by-layer to form a three-dimensional object. Powder bed fusion processes, such as selective laser sintering, high speed sintering, direct metal laser sintering, electron beam melting, and multi-jet fusion, can be suitable for producing dense, durable parts from metals, polymers, and ceramics that other subtractive manufacturing methods cannot easily produce.

[0004] For example, a multi-jet fusion process can deposit a thin layer of powder and fusing agent across a computer-controlled print bed, and the fusing agent can melt, causing the powder to bind together. After a layer is fused, another layer of powder can be spread across the first layer, so that a three-dimensional object can be built up from the bottom, without the need for custom tools or molds. SUMMARY

[0005] A method of forming an article includes depositing a plurality of individual layers of a batch of powder on top of one another in an order and fusing the plurality of individual layers together to form a workpiece and excess powder. The method also includes recovering the excess powder from the workpiece to thereby form the article. Concurrent with the recovering, the method also includes continuously analyzing a color of the excess powder to provide a color value and distributing the excess powder according to the color value by at least one of: mixing a supply powder with at least a portion of the excess powder to form a subsequent batch of powder at a certain ratio of the supply powder to the excess powder; and quarantining the excess powder from the supply powder.

[0006] In an aspect, the continuously analyzing can include determining whether and in what quantity to reuse the excess powder.

[0007] In another aspect, the continuously analyzing can include measuring the color with a colorimeter as the excess powder is recovered to determine one of: a first ratio of a supply powder to the excess powder, the first ratio corresponding to a first condition in which the color value is less than or equal to an exceptional value; a second ratio of the supply powder to the excess powder, the second ratio corresponding to a second condition in which the color value is less than or equal to a nominal value and greater than the exceptional value; a third ratio of the supply powder to the excess powder, the third ratio corresponding to a third condition in which the color value is less than or equal to a threshold value and greater than the nominal value; and a fourth condition in which the color value is greater than the threshold value. The first ratio can be less than the second ratio and the third ratio, and the second ratio can be greater than the first ratio and less than the third ratio.

[0008] In an additional aspect, the method can further include, contemporaneous with determining the second condition, reusing at least a portion of the excess powder by mixing the supply powder and the at least a portion of the excess powder together at a first ratio to form a subsequent batch of powder.

[0009] In a further aspect, the continuous analysis can include automatically adjusting at least one of the first ratio, the second ratio, and the third ratio based on the color value.

[0010] In an aspect, the method can further include, contemporaneous with determining the fourth condition, flagging the excess powder as waste powder and diverting the excess powder from the supply powder.

[0011] In another aspect, the method can further include, contemporaneous with determining the third condition, reusing at least a portion of the excess powder by mixing the supply powder and the at least a portion of the excess powder together at a third ratio to form a subsequent batch of powder.

[0012] In an additional aspect, the method can further include, contemporaneous with determining the first condition, reusing at least a portion of the excess powder by mixing the supply powder and the at least a portion of the excess powder together at a first ratio to form a subsequent batch of powder.

[0013] In a further aspect, recycling the excess powder can include at least one of manually recycling and automatically recycling the excess powder.

[0014] In an aspect, quarantining can include at least one of manually diverting and automatically diverting the excess powder from the supply powder.

[0015] In another aspect, a vehicle can include an article formed by the method.

[0016] In another embodiment, a method of forming an article includes depositing a plurality of individual layers of a batch of powder on top of one another in a sequence and fusing the plurality of individual layers together to build a three-dimensional workpiece and excess powder layer-by-layer. The method further includes recycling the excess powder from the three-dimensional workpiece to thereby form the article. In addition, the method includes continuously analyzing a color of the excess powder while recycling the excess powder to assign a plurality of color values. Contemporaneous with the continuous analysis, the method further includes determining at least one of a usable condition, in which one of the plurality of color values is less than or equal to a threshold value and flagging the excess powder as recycled powder, and a non-usable condition, in which one of the plurality of color values is greater than the threshold value and flagging the excess powder as waste powder. Contemporaneous with determining the usable condition, the method includes mixing the supply powder and the recycled powder at a ratio of the supply powder to the recycled powder. Contemporaneous with determining the non-usable condition, the method includes quarantining the waste powder from the supply powder.

[0017] A system for forming an article includes an additive manufacturing device configured to sequentially deposit and fuse together a plurality of individual layers each formed from a batch of powder to form a workpiece and excess powder. The system further includes a powder transfer mechanism configured to transfer the excess powder away from the workpiece to form the article. Additionally, the system includes a colorimeter attached to the powder transfer mechanism and configured to continuously measure a color of the excess powder as the excess powder is transferred away from the workpiece to provide a color value. The system further includes a data processor configured to continuously analyze the color value and a powder mixer configured to mix together a supply powder and the excess powder to form a subsequent batch of powder according to the color value.

[0018] In an aspect, the powder transfer mechanism can be a vacuum tube configured to manually transfer the excess powder away from the workpiece and the colorimeter can be disposed at a distal end of the vacuum tube.

[0019] In another aspect, the powder transfer mechanism can be a screw-driven transfer device defining a cavity and configured to automatically transfer the excess powder away from the workpiece. The colorimeter can be disposed within the cavity and enclosed by the screw-driven transfer device.

[0020] In an additional aspect, the additive manufacturing device can include an energy source configured to additively fuse together the plurality of layers to build the workpiece layer-by-layer therefrom.

[0021] In a further aspect, the colorimeter can be enclosed by the powder transfer mechanism to shield the excess powder from external light and can include a light source to illuminate the excess powder.

[0022] In an aspect, the data processor can be configured to determine at least one of: a first condition in which the color value is less than or equal to an exceptional value; a second condition in which the color value is less than or equal to a nominal value and greater than the exceptional value; a third condition in which the color value is less than or equal to a threshold value and greater than the nominal value; and a fourth condition in which the color value is greater than the threshold value.

[0023] In another aspect, the powder mixer can be configured to mix the supply powder and the excess powder in ratios of: a first ratio of the supply powder to the excess powder according to the second condition; a second ratio of the supply powder to the excess powder greater than the first ratio according to the third condition; and a third ratio of the supply powder to the excess powder less than the first ratio according to the first condition.

[0024] In an additional aspect, the powder transfer mechanism can be further configured to divert a waste powder from the supply powder according to the fourth condition.

[0025] The above features and advantages of the present disclosure, as well as other features and attendant advantages of particular embodiments thereof, will be readily appreciated as the same becomes better understood by reference to the following detailed description. The disclosure is explicitly considered to encompass all combinations and sub-combinations of the elements and features presented in the following detailed description and in the accompanying drawings.

[0026] The present invention comprises the following technical solutions:

[0027] 1. A method of forming an article, the method comprising:

[0028] sequentially depositing a plurality of individual layers of a batch of powder on top of one another and fusing the plurality of individual layers together to form a workpiece and excess powder;

[0029] recovering the excess powder from the workpiece to thereby form the article;

[0030] concurrent with the recovering, continuously analyzing a color of the excess powder to provide a color value; and

[0031] distributing the excess powder according to the color value by at least one of:

[0032] mixing a supply powder with at least a portion of the excess powder to form a subsequent batch of powder at a ratio of the supply powder to the excess powder; and

[0033] quarantining the excess powder from the supply powder.

[0034] 2. The method of solution 1, wherein the continuously analyzing comprises determining whether and in what quantity to reuse the excess powder.

[0035] 3. The method of solution 1, wherein the continuously analyzing comprises measuring the color with a colorimeter as the excess powder is recovered to determine one of:

[0036] a first ratio of the supply powder to the excess powder, the first ratio corresponding to a first condition in which the color value is less than or equal to an exceptional value;

[0037] a second ratio of the supply powder to the excess powder, the second ratio corresponding to a second condition in which the color value is less than or equal to a nominal value and greater than the exceptional value;

[0038] a third ratio of the supply powder to the excess powder, the third ratio corresponding to a third condition in which the color value is less than or equal to a threshold value and greater than the nominal value; and

[0039] a fourth condition in which the color value is greater than the threshold value.

[0040] wherein the first ratio is less than the second ratio and the third ratio; and

[0041] wherein the second ratio is greater than the first ratio and less than the third ratio.

[0042] 4. The method of Scheme 3, further comprising, concurrent with determining the second condition, reusing at least a portion of the excess powder by mixing the supply powder and at least a portion of the excess powder together at the first ratio to form the subsequent batch of powder.

[0043] 5. The method of Scheme 3, wherein continuously analyzing comprises automatically adjusting at least one of the first ratio, the second ratio, and the third ratio based on the color value.

[0044] 6. The method of Scheme 3, further comprising, concurrent with determining the fourth condition, flagging the excess powder as waste powder and diverting the excess powder away from the supply powder.

[0045] 7. The method of Scheme 3, further comprising, concurrent with determining the third condition, reusing at least a portion of the excess powder by mixing the supply powder and at least a portion of the excess powder together at the third ratio to form the subsequent batch of powder.

[0046] 8. The method of Scheme 3, further comprising, concurrent with determining the first condition, reusing at least a portion of the excess powder by mixing the supply powder and at least a portion of the excess powder together at the first ratio to form the subsequent batch of powder.

[0047] 9. The method of Scheme 1, wherein recovering the excess powder comprises at least one of manually recovering and automatically recovering the excess powder.

[0048] 10. The method of Scheme 1, wherein quarantining comprises at least one of manually diverting and automatically diverting the excess powder away from the supply powder.

[0049] 11. A vehicle comprising an article formed by the method of Scheme 1.

[0050] 12. A method of forming an article, the method comprising:

[0051] sequentially depositing a plurality of individual layers of a batch of powder on top of one another and fusing the plurality of individual layers together to build a three-dimensional workpiece and excess powder layer-by-layer;

[0052] reclaiming the excess powder from the three-dimensional workpiece to form the article therefrom;

[0053] continuously analyzing a color of the excess powder while reclaiming the excess powder to assign a plurality of color values; and

[0054] concurrent with the continuous analyzing, determining at least one of:

[0055] an available condition, wherein one of the plurality of color values is less than or equal to a threshold value and the excess powder is labeled as reclaimed powder; and

[0056] an unavailable condition, wherein one of the plurality of color values is greater than the threshold value and the excess powder is labeled as waste powder;

[0057] concurrent with the determining the available condition, mixing the supply powder and the reclaimed powder at a ratio of supply powder to reclaimed powder; and

[0058] concurrent with the determining the unavailable condition, quarantining the waste powder from the supply powder.

[0059] 13. A system for forming an article, the system comprising:

[0060] an additive manufacturing device configured to sequentially deposit and fuse together a plurality of individual layers each formed from a batch of powder to form a workpiece and excess powder;

[0061] a powder transfer mechanism configured to transfer the excess powder away from the workpiece to form an article;

[0062] a colorimeter attached to the powder transfer mechanism and configured to continuously measure a color of the excess powder while transferring the excess powder away from the workpiece to provide a color value;

[0063] a data processor configured to continuously analyze the color value; and

[0064] a powder mixer configured to mix together a supply powder and the excess powder to form a subsequent batch of powder according to the color value.

[0065] 14. The system of clause 13, wherein the powder transfer mechanism is a vacuum tube configured to manually transfer the excess powder away from the workpiece and the colorimeter is disposed at a distal end of the vacuum tube.

[0066] 15. A system according to option 13, wherein the powder transfer mechanism is a screw-driven transfer device, which defines a cavity and is configured to automatically transfer the excess powder away from the workpiece, and wherein the colorimeter is disposed in the cavity and enclosed by the screw-driven transfer device.

[0067] 16. The system of claim 13, wherein the additive manufacturing apparatus comprises an energy source configured to fuse multiple layers of additive material together to thereby build up the workpiece layer by layer.

[0068] 17. The system of claim 13, wherein the colorimeter is enclosed by the powder transfer mechanism to shield the excess powder from external light, and includes a light source for illuminating the excess powder.

[0069] 18. The system of claim 13, wherein the data processor is configured to determine at least one of:

[0070] a first condition, wherein the color value is less than or equal to an exceptional value;

[0071] a second condition, wherein the color value is less than or equal to the nominal value and greater than the exceptional value;

[0072] a third condition, wherein the color value is less than or equal to a threshold value and greater than the nominal value; and

[0073] The fourth condition is that the color value is greater than the threshold.

[0074] 19. The system of claim 18, wherein the powder mixer is configured to mix the supply powder and the excess powder in the following ratios:

[0075] a first ratio of the supply powder to the excess powder according to the second condition;

[0076] a second ratio of the supplied powder to the excess powder according to the third condition, the second ratio being greater than the first ratio; and

[0077] A third ratio of the supplied powder to the excess powder is provided according to the first condition, the third ratio being smaller than the first ratio.

[0078] 20. The system according to claim 18, wherein the powder transfer mechanism is further configured to divert waste powder away from the supply powder according to the fourth condition. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Figure 1 is a schematic flow chart of a method of forming an article.

[0080] Figure 2 It is for Figure 1 Schematic illustration of a system for forming an article for use in conjunction with the method of.

[0081] Figure 3 yes Figure 2 Schematic top view of a portion of an additive manufacturing apparatus of a system.

[0082] Figure 4 yes Figure 1 Schematic illustration of a portion of a method in which excess powder is recovered from a workpiece to form an article.

[0083] Figure 5 is a graphical representation of multiple color values, each of which is Figure 4 The excess powder is associated with a corresponding one of the plurality of samples.

[0084] Figure 6 yes Figure 1 A schematic flow chart of another embodiment of a method. DETAILED DESCRIPTION

[0085] Referring to the drawings, wherein like reference numerals refer to like elements, there is generally shown a method for forming an article 14 ( Figure 4 )Method 10( Figure 1 )、110( Figure 6 ) and System 12( Figure 2 ). The methods 10, 110 and system 12 may be useful for applications requiring additive manufacturing or forming of a three-dimensional object 14 from powder. In particular, the methods 10, 110 and system 12 may be useful for additively manufacturing a three-dimensional object 14 and continuously monitoring excess powder 16 (recovered during the methods 10, 110) Figure 4 ) is useful for analyzing the quality of the recovered excess powder 16. More specifically, the methods 10, 110, and system 12 can be useful for continuously or online analyzing the color of the recovered excess powder 16 as the article 14 is formed. Thus, the methods 10, 110, and system 12 can enable immediate and continuous determination of whether to reuse or dispose of the excess powder 16 as waste, and can form articles 14 having excellent quality, mechanical properties, and isotropy.

[0086] Thus, the methods 10, 110, and system 12 may be useful for automotive applications such as, but not limited to, prototyping and manufacturing articles 14 and components such as conduits, brackets, rails, tools, assembly aids, and other vehicle parts. That is, the vehicle 18 ( Figure 4) may include an article 14 formed by the method 10, 110. Alternatively, the method 10, 110 and system 12 may be useful for non-automotive applications, such as, but not limited to, prototyping articles 14 and components for aerospace, aviation, transportation, construction, industrial, dental, medical, sporting goods, and consumer product applications.

[0087] Now refer to Figures 1-4 , the method 10 comprises: mixing a batch of powder 24 ( Figure 2 and Figure 3 ) of multiple individual layers 22 ( Figure 3 ) are deposited in sequence 20( Figure 1 ) on top of each other and melting 26 the plurality of individual layers 22 ( Figure 1 ) together to form a workpiece 28 ( Figure 4 ) and excess powder 16( Figure 4 The sequential deposition 20 and melting 26 may be referred to as an additive manufacturing process for building a three-dimensional workpiece 28 layer by layer, and may be accomplished by way of non-limiting examples of powder bed fusion processes such as selective laser sintering (SLS) and multi-jet fusion (MJF).

[0088] For example, Figure 2 and Figure 3 As best shown in FIG. 1 , the system 12 for forming an article 14 includes an additive manufacturing apparatus 30, such as, but not limited to, a multi-jet fusion printer 32, and a processing system 132. The additive manufacturing apparatus 30 is configured to sequentially deposit 20 a plurality of individual layers 22 ( Figure 3 ) and melts 26 them together to form a workpiece 28 and excess powder 16. For example, the additive manufacturing device 30 may include an energy source 34 ( Figure 3 ), such as one or more melting lamps or lasers, the energy source is configured to additively fuse the plurality of layers 22 together to thereby build up the workpiece 28 layer by layer.

[0089] In one non-limiting example, the thin individual layers 22 of the batch powder 24 may be evenly spaced across the print platform 36 ( Figure 3 ) or print bed distribution, and then a print carriage with multiple inkjet-style print heads can be passed across the individual layers 22 to selectively deposit flux and refinement agents. The flux-coated sections of the individual layers 22 can then be melted using applied heat, which may cause the batch powder 24 to bond together. The refinement agent can ensure the resolution and accuracy of the workpiece 28 and printed article 14. After one of the final individual layers 22 of the workpiece 28 is melted, another individual layer 22 of the batch powder 24 can be spread across the print platform 36, and the process can be repeated until the workpiece 28 is built from the bottom up.

[0090] For more details, refer toFigure 2 As described, the batch powder 24 can be fed and loaded to a build unit at the processing system 132, and the build unit can then be inserted into the multi-jet fusion printer 32 for printing or additive manufacturing. The multi-jet fusion printer 32 can include a printer head 136 Figure 3 ), which includes a plurality of nozzles (not shown) each configured to deposit a thin individual layer 22 of the batch powder 24 onto a print platform 36 and then deposit a fusing agent and detailing agent onto the thin individual layer 22 according to computer-controlled instructions or patterns. A fusing lamp can then heat the thin layer 22 to enable the batch powder 24 to fuse in areas containing the fusing agent and form a first layer of the batch powder 24. In turn, the areas of the batch powder 24 sprayed with the detailing agent can mark a separation between the first layer and the surrounding unfused batch powder 24. Subsequently, the print platform 36 supporting the newly fused first layer can be lowered, and a new thin layer 22 of the batch powder 24, fusing agent, and detailing agent can be deposited on the first layer. This fusing and powder deposition can then be repeated until the workpiece 28 is formed or built and surrounded by the excess powder 16. That is, the workpiece 28 formed from a plurality of individual layers 22 fused together can be surrounded or encased by the excess powder 16 (i.e., batch powder 24 that did not fuse during the build or printing process).

[0091] The selection of the batch powder 24 depends on the mechanical requirements, environment, expected stresses, and operating temperatures that the article 14 will encounter during end use, the batch powder 24 can be composed of fresh or supply powder 38 combined with recycled excess powder 16 that has already undergone a printing process (as set forth in greater detail below). Each powder material has advantages and trade-offs that designers and engineers can consider when selecting the batch powder 24. Suitable supply powders 38 for forming the batch powder 24 can include, but are not limited to: nylon 11; nylon 12; polystyrene; polypropylene; polyamide / nylon composites, which can include glass beads, glass fibers, carbon fibers, and aluminum; thermoplastic polyurethane; polyether block amide; talc powder; and combinations thereof.

[0092] Referring again to Figure 1 and Figure 4 , the method 10 further includes recovering 40 the excess powder 16 from the workpiece 28 to thereby form the article 14. That is, the recovering 40 can include unpacking or deagglomerating the workpiece 28 from the surrounding excess powder 16 remaining from the build or printing process to expose the article 14. Further, the recovering 40 the excess powder 16 can include at least one of manual recovery and automated recovery of the excess powder 16 to expose the formed article 14.

[0093] For example, as Figure 4As best shown, system 12 can include a powder transfer mechanism 42 configured to transfer excess powder 16 away from workpiece 28 to form article 14. In one non-limiting example, powder transfer mechanism 42 can be a vacuum tube 142 configured to manually transfer excess powder 16 away from workpiece 28. In another non-limiting example, powder transfer mechanism 42 can be a screw-driven transfer device 242 defining an internal cavity 44 and including a transfer screw (not shown) disposed within cavity 44 configured to automatically transfer excess powder 16 away from workpiece 28. In use, an operator can position powder transfer mechanism 42 adjacent to workpiece 28 and remove and recycle excess powder 16.

[0094] Referring again to Figure 1 , method 10 further includes continuously analyzing 46 a color of excess powder 16 to provide a color value 48 Figure 5 ) concurrently with recycling 40. That is, method 10 includes continuously analyzing 46 a color as excess powder 16 is recycled, i.e., in an online or in-line operation that can incrementally (e.g., every millisecond) measure and analyze the color such that color value 48 is continuously measured and analyzed as excess powder 16 is removed from workpiece 28. In one embodiment described with reference to Figure 6 , method 10 includes repeatedly or continuously analyzing 46 a color of excess powder 16 to assign a plurality of color values 48 Figure 5 ) as excess powder 16 is recycled. Thus, continuously analyzing 46 can include determining whether and in what quantity to reuse excess powder 16 to form a subsequent batch of powder 24, as set forth in greater detail below.

[0095] For example, referring again to Figure 4, the system 12 further includes a colorimeter 50 attached to the powder transfer mechanism 42 and configured to continuously measure a color of the excess powder 16 to provide a color value 48 as the excess powder 16 is transferred away from the workpiece 28. The colorimeter 50 can be disposed at a distal end 52 of the powder transfer mechanism 42. That is, for embodiments in which the powder transfer mechanism 42 is a vacuum tube 142, the colorimeter 50 can be disposed at the distal end 52 of the vacuum tube 142 such that the colorimeter 50 measures the color of the excess powder 16 as the excess powder 16 enters the vacuum tube 142. Similarly, for embodiments in which the powder transfer mechanism 42 is a screw-driven transfer device 242, the colorimeter 50 can be disposed within the internal cavity 44 and enclosed by the screw-driven transfer device 242. That is, the colorimeter 50 can be enclosed by the powder transfer mechanism 42 to shield the excess powder 16 from external light. Accordingly, the colorimeter 50 can further include a light source 54 to illuminate the excess powder 16 as the excess powder 16 travels in front of the colorimeter 50 within the powder transfer mechanism 42 in order to ensure consistent and controlled measurement conditions.

[0096] The colorimeter 50 can be designed to measure an absorbance of the excess powder 16 to a particular wavelength of light and, thus, can be able to provide a plurality of color values 48 as the excess powder 16 is removed and recovered from the workpiece 28. In one non-limiting example, the colorimeter 50 can provide the color values 48 according to the International Commission on Illumination color space (CIELAB), in which L* refers to lightness and defines black as 0 and white as 100; a* refers to green and red opponent color, in which negative values are assigned to green and positive values are assigned to red; and b* refers to blue and yellow opponent color, in which negative values are assigned to blue and positive values are assigned to yellow.

[0097] Generally, a higher L* value (i.e., a lighter color) can be associated with better flowability and spreadability of the powder. Higher chroma (i.e., higher a* and b* values) can indicate that the powder is aging or chemically changing over time and use. Quantitatively representing the color as the color values 48 can enable excellent powder quality control and reproducibility in the methods 10, 110 and the system 12.

[0098] Referring again to Figure 4 and Figure 5 , the colorimeter 50 can continuously measure the color of the excess powder 16 as the excess powder 16 passes or flows in front of the colorimeter 50 within the internal cavity 44 of the powder transfer mechanism 42 as the excess powder 16 is recovered from the workpiece 28. That is, the colorimeter 50 can provide a plurality of color values 48 Figure 5 at continuous intervals (e.g., in increments without gaps or interruptions) such that the quality of the excess powder 16 can be monitored. By way of non-limiting example, the colorimeter 50 can provide the b* color value 48 of the excess powder 16 along Figure 5), the b* color value 48 is related to the relative whiteness 56 / yellowness 58 of the excess powder 16. Generally speaking, fresh or supply powder 38 and resulting excess powder 16 may become more yellow 58 and less white 56 as the powder 16, 38 deteriorates (due to oxidation) and discolors. Similarly, excess powder 16 recovered from the immediate vicinity of the workpiece 28 may deteriorate more quickly than excess powder 16 in other areas due to exposure to relatively high heat during melting 26. This deterioration may contribute to the formation of undesirable articles 14.

[0099] Therefore, due to the more yellow 58 ( Figure 5 Excess powder 16 (often referred to as excess powder 16) can indicate that subsequent batches of powder 24 are about to experience performance deviations, and thus the b* color value 48 can be correlated with the quality of the excess powder 16 and can determine whether and in what amount the excess powder 16 can be recycled and reused in subsequent batches of powder 24. By monitoring the color value 48 of the excess powder 16 profile during recovery from the workpiece 28, the method 10 can include correlating color changes with optimal moisture content, the presence of impurities, the degree of agglomeration, and reusability of the excess powder 16. This can ensure high-quality supply powder 38 and batches of powder 24 feedstock to achieve consistent melting behavior in the additive manufacturing device 30 and the properties of the final article 14.

[0100] Therefore, refer again to Figure 1 , the method 10 further includes distributing 60 the recycled or used or excess powder 16 according to the color value 48 by at least one of the following steps: mixing 62 the supply powder 38 with at least a portion of the excess powder 16 in a ratio of supply powder 38 to excess powder 16 to form a subsequent batch of powder 24; and isolating 64 the excess powder 16 from the supply powder 38. That is, with reference to Figure 6 In one embodiment, the method 110 includes, concurrently with the continuous analysis 46, determining 66 at least one of the following: availability conditions 68 ( Figure 5 ), wherein one of the plurality of color values ​​48 is less than or equal to a threshold value 70 ( Figure 5 ) and the excess powder 16 is marked as recycled powder 72 ( Figure 2 ); and unavailable condition 74( Figure 5 ), wherein one of the plurality of color values ​​48 is greater than a threshold value 70 and the excess powder 16 is marked as waste powder 76 ( Figure 2 As explained in more detail below, determining 66 the usable condition 68 and the unusable condition 74 may enable continuous and / or immediate decisions regarding the reuse or disposal of excess powder 16 .

[0101] Reference again Figure 1, method 10 further includes distributing 60 the excess powder 16 according to the color value 48 by at least one of: mixing 62 the supply powder 38 with at least a portion of the excess powder 16 at a ratio of the supply powder 38 to the excess powder 16 to form the subsequent batch of powder 24; and quarantining 64 the excess powder 16 from the supply powder 38. That is, in one embodiment, method 110 includes: concurrently with determining 66 the available condition 68 Figure 5 Concurrently with determining 66 the unavailable condition 74 Figure 5

[0102] For example, as referenced above Figure 5 As best described, the continuous analysis 46 can include measuring a color with the colorimeter 50 to produce the color value 48 upon recycling the excess powder 16, thereby determining one of: a first ratio of the supply powder 38 to the excess powder 16, the first ratio corresponding to a first condition 78 in which the color value 48 is less than or equal to the exceptional value 80; a second ratio of the supply powder 38 to the excess powder 16, the second ratio corresponding to a second condition 82 in which the color value 48 is less than or equal to the nominal value 86 and greater than the exceptional value 80; a third ratio of the supply powder 38 to the excess powder 16, the third ratio corresponding to a third condition 84 in which the color value 48 is less than or equal to the threshold value 70 and greater than the nominal value 86; and a fourth condition 88 in which the color value 48 is greater than the threshold value 70.

[0103] The second ratio can be a standard or nominal ratio, and can be greater than the first ratio and less than the third ratio. The first ratio can be less than the second ratio and the third ratio. For example, each of the first ratio, the second ratio, and the third ratio can be from 50:50 (supply powder 38:excess powder 16) to 20:80 (supply powder 38:excess powder 16) or from 40:60 (supply powder 38:excess powder 16) to 30:70 (supply powder 38:excess powder 16).

[0104] ​By virtue of being set up in-line with the powder transfer mechanism 42, this continuous analysis of the excess powder 16 by the colorimeter 50 can allow for the reuse of some or a portion of the excess powder 16. For example, certain areas of the workpiece 28 can be subjected to longer fusing times or higher temperatures than other areas due to variations in the amount of fusing agent or detailing agent applied to the individual layers 22 as the workpiece 28 is formed. The excess powder 16 surrounding these areas can degrade more quickly than the excess powder 16 in other areas of the workpiece 28. The method 10, 110 and system 12 allow for the reuse of excess powder 16 from certain areas of the workpiece 28, while excess powder 16 from other areas of the workpiece 28 can be marked as waste powder 76 and quarantined from the fresh supply powder 38 for use in the formation of subsequent articles 14.

[0105] Referring now to Figure 2 The system 12 also includes a data processor 90 configured to continuously analyze 46 the color values 48 and determine at least one of the first condition 78, the second condition 82, the third condition 84, and the fourth condition 88. The data processor 90 can continuously analyze and / or store the color values 48 for each sample of the excess powder 16 and provide input for subsequent batches of powder 24 regarding potential adjustments to the amount of supply powder 38 and excess powder 16. As such, the continuous analysis 46 can include at least one of the first ratio, the second ratio, and the third ratio being automatically adjusted based on the color values 48.

[0106] As explained in greater detail below, the data processor 90, which can be part of a computer controlling the system 12, can provide input signals such that the computer commands the powder transfer mechanism 42 to divert excess powder 16 that does not meet the available condition 68 or boundary to a waste disposal location, or to further dilute with fresh supply powder 38 until the quality specification based on the color values 48 is met. Thus, multiple color values 48 can be used to automatically adjust the ratio of supply powder 38 to excess powder 16 (i.e., the first ratio, the second ratio, or the third ratio) for excess powder 16 that is marginal in quality to produce subsequent batches of powder 24 having acceptable quality. The data processor 90 and / or computer controls can also store multiple color values 48 for each round or build of each article 14 to obtain a history for a given supply powder 38 and excess powder 16 to provide troubleshooting options for future articles 14. As such, the method 10, 110 and system 12 can implement computer and / or machine learning to achieve a maximization of the reuse of excess powder 16.

[0107] Referring again to Figure 5The first condition 78 can result in reducing the amount of fresh supply powder 38. That is, the method 10 can include, concurrent with determining the first condition 78, reusing the portion of the excess powder 16 by mixing together the supply powder 38 and the portion of the excess powder 16 at a first ratio to form the subsequent batch of powder 24 for forming the next article 14 via the sequential depositing 20, fusing 26, and recycling 40 as set forth above.

[0108] The second condition 82 can result in not adjusting the ratio of the supply powder 38 to the excess powder 16. That is, the method 10 can include, concurrent with determining the second condition 82, maintaining the second ratio of the supply powder 38 to the excess powder 16 to form the subsequent batch of powder 24 suitable for forming the next article 14.

[0109] The third condition 84 can result in increasing the amount of fresh supply powder 38. That is, the method 10 can include, concurrent with determining the third condition 84, reusing at least a portion of the excess powder 16 by mixing together the supply powder 38 and the portion of the excess powder 16 at a third ratio to form the subsequent batch of powder 24 suitable for forming the next article 14.

[0110] The fourth condition can result in flagging the excess powder 16 as waste powder 76 and disposing of the excess powder 16 as waste such that the excess powder 16 is not reused. That is, the method 10 can include, concurrent with determining the fourth condition, flagging the excess powder 16 as waste powder 76 and diverting the excess powder 16 from the supply powder 38. In particular, the powder transfer mechanism 42 can be further configured to divert the waste powder 76 from the supply powder 38 according to the fourth condition 88. For example, the powder transfer mechanism 42 Figure 3 ) can be equipped with a diverter valve that automatically diverts the excess powder 16 from the supply powder 38 according to the fourth condition 88. Alternatively, the powder transfer mechanism 42 can be manually positioned to divert the excess powder 16 from the supply powder 38 according to the fourth condition 88. That is, the quarantine isolation 64 can include at least one of manually diverting and automatically diverting the excess powder 16 from the supply powder 38.

[0111] Referring again to Figure 2 , the system 12 further includes a powder mixer 92 configured to mix together the supply powder 38 and the excess powder 16 according to the color value 48 to form the subsequent batch of powder 24. That is, the powder mixer 92 can be configured to mix together the supply powder 38 and the excess powder 16 at the first ratio, the second ratio, and the third ratio.

[0112] Advantageously, the methods 10, 110 and systems 12 allow for continuous, in-line color measurement and quality monitoring of the excess powder 16 generated during the formation of the articles 14, and thus allow for automatic adjustment of the ratio of the supply powder 38 to the excess powder 16 for forming subsequent batches of powder 24. This continuous analysis allows for variable recycling or re-use rates, and enables a relatively high degree of confidence in the quality of the powder when compared to a single sample quality measurement or color value 48 for each article 14. Additionally, the methods 10, 110 and systems 12 allow for relatively high re-use of the recycled excess powder 16, and provide a superior understanding of the incoming powder quality. As such, it can not be necessary to take offline samples and color measurements of the excess powder 16, and the powder transfer mechanism 42 can automatically divert out-of-spec excess powder 16 from the fresh supply powder 38 to prevent contamination of the subsequent batches of powder 24 with unusable excess powder 16. That is, the methods 10, 110 and systems 12 allow for continuous, in-line analysis of the color of the excess powder 16, rather than post-hoc analysis of the excess powder 16, to prevent contamination of the supply powder 38 and formation of unacceptable articles 14.

[0113] The described embodiments of the present disclosure are intended to be merely illustrative of the non-limiting examples and other embodiments can take various and alternative forms. Additionally, the appended drawings are not necessarily drawn to scale, and can present a somewhat simplified representation of various features of the present disclosure, including, for example, specific dimensions, orientations, locations, and shapes. Details associated with such features can be determined, in part, by the intended application and use environment of the described embodiments.

[0114] For the purposes of this description, unless explicitly stated otherwise, the use of the singular includes the plural and vice versa, the use of the term "and" includes both the conjunctive and disjunctive sense, and the use of the terms "including," "containing," "comprising," "having," and the like means "including but not limited to." Further, words of approximation such as "about," "nearly," "substantially," "generally," "approximately," and the like, as used herein mean "in a range of or nearly in a range of," or "within 0-5% of," or "within acceptable manufacturing tolerances of," or logical combinations thereof. As used herein, a component that is "configured to" perform a particular function is capable of performing the particular function without

[0115] The detailed description and the accompanying drawings or diagrams support and describe the present teachings, but the scope of the present teachings is defined solely by the claims. While the best mode and other embodiments of the present teachings have been described in detail, numerous alternatives will be readily apparent to those skilled in the art without departing from the true spirit and scope of the present teachings defined by the claims. Moreover, the disclosure expressly includes combinations and sub-combinations of the elements and features presented above and below.

Claims

1. A method of forming an article, the method comprising: sequentially depositing a plurality of individual layers of a batch of powder on top of one another and fusing the plurality of individual layers together to form a workpiece and excess powder; recovering the excess powder from the workpiece to thereby form the article; concurrently with the recovering, continuously analyzing a color of the excess powder to provide a color value; and distributing the excess powder according to the color value by at least one of: mixing a supply powder with at least a portion of the excess powder to form a subsequent batch of powder at a ratio of the supply powder to the excess powder; and quarantining the excess powder from the supply powder.

2. The method of claim 1, wherein, The continuously analyzing includes determining whether and in what quantity to reuse the excess powder.

3. The method of claim 1, wherein, The continuously analyzing includes measuring the color with a colorimeter as the excess powder is recovered to determine one of: a first ratio of the supply powder to the excess powder, the first ratio corresponding to a first condition in which the color value is less than or equal to an exceptional value; a second ratio of the supply powder to the excess powder, the second ratio corresponding to a second condition in which the color value is less than or equal to a nominal value and greater than the exceptional value; a third ratio of the supply powder to the excess powder, the third ratio corresponding to a third condition in which the color value is less than or equal to a threshold value and greater than the nominal value; and a fourth condition in which the color value is greater than the threshold value; wherein the first ratio is less than the second ratio and the third ratio; and wherein the second ratio is greater than the first ratio and less than the third ratio.

4. The method of claim 3, further comprising: Concurrent with determining the second condition, reusing at least a portion of the excess powder by mixing the supply powder and at least a portion of the excess powder together to form the subsequent batch of powder at the first ratio.

5. The method of claim 3, wherein, The continuously analyzing includes automatically adjusting at least one of the first ratio, the second ratio, and the third ratio according to the color value.

6. The method of claim 3, further comprising: Concurrent with determining the fourth condition, flagging the excess powder as waste powder and diverting the excess powder from the supply powder.

7. The method of claim 3, further comprising: Concurrent with determining the third condition, reusing at least a portion of the excess powder by mixing the supply powder and at least a portion of the excess powder together to form the subsequent batch of powder at the third ratio.

8. The method of claim 3, further comprising: Concurrent with determining the first condition, reusing at least a portion of the excess powder by mixing the supply powder and at least a portion of the excess powder together to form the subsequent batch of powder at the first ratio.

9. A method of forming an article, the method comprising: sequentially depositing a plurality of individual layers of a batch of powder on top of one another and fusing the plurality of individual layers together to build a three-dimensional workpiece and excess powder layer-by-layer; recovering the excess powder from the three-dimensional workpiece to thereby form the article; continuously analyzing a color of the excess powder as the excess powder is recovered to assign a plurality of color values; and concurrent with the continuously analyzing, determining at least one of: a first ratio of a supply powder to the excess powder, the first ratio corresponding to a first condition in which a first color value of the plurality of color values is less than or equal to an exceptional value; a second ratio of the supply powder to the excess powder, the second ratio corresponding to a second condition in which a second color value of the plurality of color values is less than or equal to a nominal value and greater than the exceptional value; a third ratio of the supply powder to the excess powder, the third ratio corresponding to a third condition in which a third color value of the plurality of color values is less than or equal to a threshold value and greater than the nominal value; and a fourth condition in which a fourth color value of the plurality of color values is greater than the threshold value. an available condition, wherein one of the plurality of color values is less than or equal to a threshold value and designates the excess powder as recycled powder; and an unavailable condition, wherein one of the plurality of color values is greater than the threshold value and designates the excess powder as waste powder; concurrent with determining the available condition, mixing the supply powder and the recycled powder at a certain ratio of supply powder to recycled powder; and concurrent with determining the unavailable condition, quarantining the waste powder from the supply powder.

10. A system for forming an article, the system comprising: an additive manufacturing device configured to sequentially deposit and fuse together a plurality of individual layers each formed from a batch of powder to form a workpiece and excess powder; a powder transfer mechanism configured to transfer the excess powder away from the workpiece to form an article; a colorimeter attached to the powder transfer mechanism and configured to continuously measure a color of the excess powder as the excess powder is transferred away from the workpiece to provide a color value; a data processor configured to continuously analyze the color value; and a powder mixer configured to mix together a supply powder and the excess powder according to the color value to form a subsequent batch of powder.

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