POWDER-BASED ADDITIVE MANUFACTURING PLANT WITH BLOWER CLEANING DEVICE
The cleaning device with a gas flow and brushes addresses the issue of powder agglomeration in additive manufacturing by dislodging and removing clumps, ensuring a smooth manufacturing process.
Patent Information
- Application Number
- FR2016061003
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2016-11-14
- Publication Date
- 2025-11-28
- Estimated Expiration
- 2036-11-14
AI Technical Summary
Powder used in powder-based additive manufacturing facilities accumulates and agglomerates in the gaps between the powder deposition means and the casing, forming clumps that hinder the manufacturing process.
A cleaning device with a blowing device and a suction device is installed upstream of the deposition zone to dislodge agglomerates using a gas flow and brushes, followed by a brushing device downstream to ensure thorough removal.
Effectively removes agglomerates from the powder deposition system, maintaining the integrity and efficiency of the manufacturing process by preventing powder accumulation.
Smart Images
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Abstract
Description
Because the powder used in powder-based additive manufacturing facilities is both volatile and sticky, it tends to accumulate and then agglomerate in various places in the layering device 14 during the powder deposition cycles. In particular, it was observed that powder accumulates and forms agglomerates 38 in the gaps between the powder deposition means 18 and the casing 30 of the coating device 14. Figure 2 illustrates in particular that agglomerates 38 form between the second side walls 34 and the metering cylinder 22. To remedy this, the installation 10 includes a first cleaning device 40, located on the path of the layering device 14 upstream of the deposition zone P, considering the path in the direction of starting zone A towards arrival zone B. The first cleaning device 40 includes a first blowing device 42, visible more particularly in figures 3 and 4, configured to blow a flow of gas onto at least one surface of the powder deposition means 18. In this case, the gas blown by the blowing device is the ambient gas of the deposition zone P, here dinitrogen, but it could also be argon, hydrogen or another neutral gas. The first blowing device 42 includes means 44 for directing the gas flow in a predetermined direction. More specifically, the directing means include a blowing nozzle 46 having a plurality of aligned orifices 48 directed parallel to the predetermined direction. The predetermined orientation direction is chosen such that the gas flow reaches a surface of the casing 30 opposite the powder deposition means 18 during the passage of the coating device 14. Preferably, the predetermined orientation direction is also such that the gas flow reaches, during the passage of the coating device 14, a surface of the metering cylinder 22, as well as a surface of the powder smoothing means 35 such as the surface of the smoothing cylinder 36. Thus, in the first embodiment shown in Figures 1 to 7, the The predetermined orientation direction is chosen to be normal to the plane of the platform 12 and directed towards the layering device 14. This orientation direction is therefore perpendicular to the translation axis X of the layering device 14 and has a direction opposite to that in which gravity acts. The choice of such an orientation direction, represented by the arrows O on figure 4, makes it possible to direct the gas flow F from the orifices 48 towards the surface of the second lateral walls 34 of the housing 30 located opposite the metering cylinder 22. The orifices 48 are preferably aligned in a direction perpendicular to the translation axis X of the coating device 14 and to the orientation direction O. In this way, a gas flow F from the orifices 48 reaches the surface of the metering cylinder 22 over all, or almost all, the longitudinal direction of the second lateral walls 34 of the housing 30. This choice also makes it possible to reach the surfaces of the dosing cylinder 22 and the smoothing cylinder 36 during the passage of the layering device 14. In particular, the distance that can be reached by the gas flow F, as well as the speed of this flow F, will be adjusted in order to dislodge the agglomerates 38 of powder located between the second lateral walls 34 and the metering cylinder 22, as can be seen in Figure 4. The cleaning device 40 may also include sealing means 50 separating in a powder-tight manner a first cleaning zone N1, where the gas flow is blown over at least one surface of the powder deposition means 18, from the powder deposition zone P. Preferably, these sealing means 50 include at least one brush 52 with bristles 54 that can bend over the passage of the coating device 14. The brush 52 makes it possible to separate the first cleaning zone N1, in which the first blowing device 42 is located, from the powder deposition zone P. More specifically, as shown in Figure 3, the length of the brush bristles 52 is chosen to ensure a seal between the cleaning zone N1 and the powder deposition zone P when the coating device 14 passes through the first cleaning zone N1. To this end, the bristles 54 of the brush 52 extend in a direction perpendicular to the surface of the powder deposition means 18 with which they come into contact. Thus, the bristles extend in the same direction as the flow direction O. In addition, the bristles 52 of the brush are long enough to be flush with one of the second side walls 34 of the housing 30 when the blow nozzle 46 is located opposite the metering cylinder 22 and thus perform its sealing function. Consequently, there will also be contact between the bristles 54 and the surface of the metering cylinder 22 and / or the smoothing cylinder 36 as the coating device 14 passes through the first cleaning zone N1. Thus, in addition to providing a sealing function, the brush 52 can also brush the surface of the metering cylinder 22 and / or the smoothing cylinder 36 as the coating device 14 passes over them. This helps to dislodge any powder clumps that may have accumulated on the surface of these metering cylinders 22 and 36. In the embodiment shown in Figures 1 to 7, the sealing means 50 comprise only one brush 52 located downstream of the cleaning zone N1 and the first blowing device 42. However, in a variant not shown, the sealing means 50 comprise two brushes 52, the cleaning zone being delimited by these two brushes 52 and the blowing device 42 being located between the two brushes 52. The second brush 52 will in this case preferably be identical to the first, and arranged symmetrically with respect to the alignment direction of the orifices 42 (i.e. symmetrical with respect to the blowing nozzle 46). Advantageously, to remove the agglomerates 38 dislodged by the first blowing device 42 before they reach the powder deposition zone P, the cleaning device 40 further includes a first suction device 56. This suction device 56 evacuates the powder sucked up by this first suction device 56 to an area of the installation, called the first dust removal zone D1, which is isolated from the powder deposition zone P. In the first embodiment shown in figures 1 to 7, the first suction device 56 includes a first evacuation conduit 58 located under the first cleaning zone N1, which extends in a direction normal to the plane of the apron 12 and which is directed in the opposite direction to that of the layering device 14. For clarity, the elements of the first suction device 56 other than the first evacuation duct 58 have not been shown. Preferably, the first exhaust duct 56 is located at the right of the first blowing device 42, and in particular at the right of the blowing nozzle 46, therefore below it in Figure 3. For example, the first exhaust duct 58 has a convergent shape in the opposite direction to the first suction device 56. Figure 5 shows a histogram of a cleaning cycle carried out during a manufacturing process according to the invention, comprising a cleaning step. This manufacturing process includes a cleaning step during in which the layering device 14 performs a cleaning path on which the cleaning device 40 is located, this cleaning path being alternating. For example, as illustrated in Figure 5, which shows a histogram of a cleaning cycle, the coating device 14 makes three back-and-forth movements along the cleaning path. It will therefore pass through the cleaning zone N1 six times. During this time, there will be six contacts between the brush 52 and the metering cylinder 22 and the smoothing cylinder 36. Preferably, the first suction device 56 performs its suction function throughout the entire cleaning step. The same is preferably true for the blowing device 42. Furthermore, as can still be seen on the histogram of figure 5, during the cleaning step, the smoothing cylinder 36 is rotated, which makes it easier to detach any agglomerates 38 of powder by the flow of gas F sent by the first blowing device 42. This rotation preferably takes place throughout the entire duration of the cleaning step. In order to more specifically dislodge the agglomerates of powder that may accumulate on the surfaces of the smoothing cylinder 36 and / or the dosing cylinder 22, the installation 10 includes a second cleaning device 60, located downstream of the deposition area P. This second cleaning device 60 includes a brushing device 62 for brushing at least one surface of the powder smoothing means 35, here that of the smoothing cylinder 36. The brushing device 62 includes for this purpose at least one brush with bristles that can bend over the passage of the coating device 14. In the embodiment shown in figures 1 to 7, the second cleaning device 60 includes in particular two parallel brushes extending in a substantially longitudinal direction, an upstream brush 64 and a downstream brush 66 (the terms upstream and downstream being understood in relation to the path of the coating device 14 from the starting zone A to the arrival zone B). In the example shown in figures 1 to 7, and as can be seen in particular in figure 6, the upstream brush 64 and the downstream brush 66 are placed in such a way that the coating device 14 moves locally in a direction substantially perpendicular to the longitudinal direction of the brushes 64, 66. In this case, the upstream brush 64 and the downstream brush 66 extend along an axis perpendicular to the translation direction X of the coating device 14. Furthermore, the bristles 68 of the upstream brush 64 and the bristles 70 of the downstream brush 66 extend in a direction perpendicular to the surface of the smoothing means 35 of the powder with which they come into contact, here of the smoothing cylinder 36. The length of the bristles 68 of the upstream brush 64 and the bristles 70 of the downstream brush 66 are chosen so that the upstream brush 64 and the downstream brush 66 can brush the surface of the straightening cylinder 36. Preferably, the brushing device 62, and therefore the upstream brushes 64 and downstream brushes 66, also brushes at least one surface of the powder deposition means 18, here that of the metering cylinder 22. Moreover, this brushing is advantageously carried out perpendicular to the surface of the metering cylinder 22. In the example shown in Figures 1 to 7, the bristles 68 of the upstream brush 64 and the bristles 70 of the downstream brush 66 are the same length. However, in a variant not shown, the bristles of the two upstream brushes 64 and downstream brushes 66 are of different lengths so as to adapt to the dimensions of the metering cylinder 22 and the smoothing cylinder 36 when their diameters differ from each other, or so as to adapt to the different heights of the metering cylinder 22 and the smoothing cylinder 36 relative to the deposition zone P. The second cleaning device 60 being placed downstream of the powder deposition zone P, the upstream brush 64 separates a second cleaning zone N2, where the brushing of the powder deposition means 18 takes place, from the deposition zone P. Thus, preferably, the length of the bristles 68 of the upstream brush 64 is chosen so as to achieve a seal between the second cleaning zone N2 and the powder deposition zone P at the time of the passage of the coating device 14 in the cleaning zone N2. In this case, the bristles 68 of the brush are long enough to touch one of the second side walls 34 of the housing 30 when the blow nozzle 46 is located opposite the metering cylinder 22 and thus perform a powder sealing function, as in the first cleaning device 40. As in the first cleaning device 40, the second cleaning device 60 may include a powder suction device. This second powder suction device 72 discharges the powder it suctions to a second dust removal zone D2 isolated from the powder deposition zone P. For this purpose, the second suction device 72 includes a suction nozzle 74 comprising a suction orifice 76 in the form of a slot with substantially rectangular edges made in the apron 12. The suction port 76 constitutes the inlet of an evacuation conduit 78 linking the cleaning zone N2 to the second dust removal zone D2. Preferably, and as can be seen more particularly in Figure 7, one of the two brushes of the brushing device 62, here the downstream brush 66, is placed at the edge of the suction port 76. To better facilitate the evacuation of the aspirated powder by the second aspiration device 72, the latter includes means for guiding the aspirated powder 80 to guide the powder towards the second evacuation conduit 78. These guiding means 80 include in particular a ramp 82 located opposite the downstream brush 66, the wall 82P of the ramp being opposite a wall 84P of the body 84 of the downstream brush 66 forming an introduction conduit 86 of the powder towards the rest of the evacuation conduit 78. In the example shown in figures 1 to 7, the second drainage conduit 78 includes a first part 87 extending under the deck 12, in a direction parallel to the translation axis X of the layering device 14. Then, the second evacuation conduit 78 includes a second part consisting of an evacuation tube 88 extending in a direction normal to the plane of the deck 12. The first end of this tube 88 is connected to the first part 87 and the second end of this tube 88 is connected to the second dust removal zone D2, into which the aspirated powder falls under the effect of suction and / or gravity. Similar to the first cleaning device 40, an additive manufacturing process involving the second cleaning device 60 includes a cleaning step during which the coating device 14 follows a cleaning path along which the second cleaning device 60 is located, the cleaning path being alternating. Preferably, during this cleaning step, the smoothing cylinder 36 is rotated to better dislodge any powder agglomerates using the upstream brushes 64 and downstream brushes 66. It should be noted that in the first embodiment according to the invention shown in figures 1 and 7, the installation 10 includes a first 40 and a second cleaning device 60, but it may very well include only one of the two. Figures 8 and 9 show a second unclaimed embodiment of the installation 10, the elements of which common to the previous embodiment are designated by similar references. Like the installation of the first embodiment according to the invention, the installation 10 of the second unclaimed embodiment includes a powder coating device 14 movable along a path connecting a starting zone A and an arrival zone B. This coating device 14 includes means 18 for depositing powder to deposit powder in a powder deposition zone P located between the starting zone A and the arrival zone B. In contrast, in this second, unclaimed embodiment, the powder dispensing means 18 comprise, instead of a metering cylinder, a sliding drawer. These dispensing means are not shown in the figures. Like the first and second cleaning devices, the third cleaning device 90 is located on the path of the powder deposition device 14 and is equipped with means for smoothing 35 the dose of powder delivered by the powder deposition means 18, including in particular a smoothing cylinder 36. The installation 10 of the second unclaimed embodiment also includes a cleaning device, or third cleaning device 90, located upstream of the powder deposition zone P. The third cleaning device 90 includes scraping means 92 equipped with a plurality of longitudinal scraping teeth 94, parallel to each other, which scrape the surface of the smoothing cylinder 36 tangentially to that surface. In particular, the layering device 14 moves locally along the path in a direction substantially parallel to the longitudinal direction of the scraping teeth 94 of the scraping means 92. In the example shown in Figures 8 and 9, the scraping teeth 94 of the scraping means 92 therefore extend along the X axis. Preferably, the scraping means 92 comprise at least one comb comprising the plurality of scraping teeth 94. The scraping teeth 94 of the comb are substantially all of the same length. In this second unclaimed embodiment, the scraping means 94 comprise a first comb 96 forming a first row of teeth 94 and a second comb 98 forming a second row of teeth 94, the first and second rows of teeth 94 being parallel. In order to obtain more efficient scraping of the surface of the smoothing cylinder 36, the free ends of the teeth 94 of the first comb 96 are offset longitudinally with respect to the free ends of the teeth 94 of the second comb 98. In this case, the first comb 96 and the second comb 98 share the same body 100. More specifically, the teeth 94 of the first comb 96 and the second comb 98 extend from the same plane, here the same surface 102 of the body 100. Furthermore, the length of the teeth 94 of the first comb 96 is greater than the length of the teeth of the second comb 98. In order to ensure their durability, the teeth 94 of the scraping means 92 are preferably made of metallic material. More specifically, the teeth of the 92 scraping devices are made of steel Demagnetized stainless steel is used, firstly, to prevent the formation of oxides and their contamination of the powder, and secondly, to allow its use in metal powder additive manufacturing systems. An example of such steel is demagnetized 301 stainless steel. In this second unclaimed embodiment, as in the first embodiment, the cleaning device includes a blowing device 42 configured to blow a flow of gas onto at least one surface of the smoothing cylinder 36. Since this blowing device 42 is very similar to that of the installation in the first embodiment, it will not be described in more detail here. It will only be specified that, similarly to the first embodiment, this blowing device 42 comprises a blowing nozzle 46 equipped with a plurality of aligned orifices 48 directed towards the surface of the smoothing cylinder 36, and that the coating device 14 moves locally along the path in a direction substantially perpendicular to the alignment direction of the orifices 48 of the blowing nozzle 46. In the same way as with the first cleaning device 40 or the second cleaning device 60, an additive manufacturing process involving the third cleaning device 90 includes a cleaning step during which the layering device 14 performs a cleaning path on which the third cleaning device 90 is located, the cleaning path being alternating. Preferably, during this cleaning step, the smoothing cylinder 36 is rotated to better dislodge any agglomerates of powder using the combs 96, 98 in the opposite direction to the advance of the smoothing cylinder 36 due to the movement of the coating device 14. For example, the teeth 94 of the scraping means 92 extending from upstream to downstream (from right to left in figures 8 and 9), the coating device 14 moves from downstream to upstream and the smoothing cylinder 36 rotates counterclockwise during the cleaning. It should be noted that in the second unclaimed embodiment shown in Figures 8 and 9, the installation 10 includes a single cleaning device 90, but it may very well include several, and in particular one and / or the other of the first 40 and second 60 cleaning devices. In general, the invention is not limited to the embodiments presented and other embodiments will be obvious to a person skilled in the art. For example, any combination of elements from the different cleaning devices described above could be considered.
Claims
DEMANDS 1. Powder-based additive manufacturing installation (10), comprising a powder layering device (14) that can be moved alternately along a path connecting a starting zone (A) and an ending zone (B), characterized in that the coating device (14) comprises powder deposition means (18) including storage means comprising a hopper (20) and powder dosing means comprising a rotating dosing cylinder (22) provided with a powder dosing cavity (24) for depositing powder into a powder deposition zone (P) located between the starting zone (A) and the receiving zone (B) and in that the installation further includes a cleaning device (40) for the coating device (14) located on the path of the latter, the cleaning device (40) including a blowing device (42) configured to blow a gas flow in an orientation direction (O), which is perpendicular to the direction of the path of the coating device (14) and in the opposite direction to that in which gravity acts, on at least one surface of the powder deposition means (18).
2. Manufacturing installation (10) according to claim 1, wherein the cleaning device (40) includes a powder suction device (56) to evacuate the powder suctioned by this suction device (56) to an area of the installation, called the dust removal area (D1), which is isolated from the powder deposition area (P).
3. Manufacturing installation (10) according to any one of the preceding claims, wherein the cleaning device (40) includes sealing means (50) separating in a powder-tight manner a cleaning zone (N) where the gas flow is blown over at least one surface of the powder deposition means (18) from the powder deposition zone (P).
4. Manufacturing installation (10) according to claim 3, wherein the sealing means (50) comprise a brush (52) provided with bristles (54) capable of bending over the passage of the coating device (14).
5. Manufacturing installation (10) according to claims 3 and 4 taken together, wherein the sealing means (50) comprise two brushes (52), the cleaning area (N) being delimited by the two brushes (52) and the blowing device (42) being located between the two brushes (52).
6. Manufacturing installation (10) according to claim 4 or 5, wherein the bristles (54) of the brush (52) extend in a direction perpendicular to the surface of the powder deposition means (18) with which they come into contact.
7. Manufacturing installation (10) according to any one of the preceding claims, wherein the cleaning device (40) is located upstream of the powder deposition zone (P), considering the path in the direction of starting zone (A) to arrival zone (B).
8. Manufacturing installation (10) according to any one of the preceding claims, wherein the blowing device (42) includes means for directing the gas flow in the direction of orientation (O).
9. Manufacturing installation (10) according to claim 8, in which the blowing device (42) comprises a blowing nozzle (46) provided with a plurality of orifices (48) aligned and directed towards the orientation direction (O).
10. Manufacturing installation (10) according to claim 8 or 9 in which, the coating device (14) comprising a housing (30) delimiting a volume in which the powder deposition means (18) are located, the orientation direction (O) is such that the gas flow reaches a surface (34) of the housing (30) opposite the powder deposition means (18) during the passage of the coating device (14).
11. Manufacturing installation (10) according to any one of claims 8 to 10, wherein the orientation direction (O) is such that the gas flow reaches a surface of the metering cylinder (22) during the passage of the coating device (14).
12. Manufacturing installation (10) according to any one of claims 8 to 11, wherein the coating device (14) further comprising powder smoothing means (35), for example a smoothing cylinder (36), the orientation direction (O) is such that the gas flow reaches a surface of the powder smoothing means (35), for example a surface of the smoothing cylinder (36), during the passage of the coating device (14).
13. Powder-based additive manufacturing process using a powder-based additive manufacturing installation (10), comprising a cleaning step of an element of the manufacturing installation (10), characterized in that the manufacturing installation (10) is according to any one of claims 1 to 12, and in that, during the cleaning step, the coating device (14) is made to carry out a cleaning path on which the cleaning device (40) is located, the cleaning path being alternating.
14. A manufacturing method according to claim 13, using a manufacturing installation (10) according to claim 2, wherein the suction device (56) performs its suction function throughout the entire cleaning step.
15. Manufacturing method according to claim 14 of a manufacturing installation (10) according to claim 12, wherein, during the cleaning step, the smoothing cylinder (36) is rotated.