POWDER DISPENSING SYSTEM FOR THREE-DIMENSIONAL PRINTING

Abstract

Powder dispenser (9) for a three-dimensional printing device (1), the dispenser (9) comprising: - a top plate arranged horizontally and having a top passage vertically through the top plate, - an intermediate plate arranged horizontally below the top plate, the intermediate plate having an intermediate passage vertically through the intermediate plate, the intermediate plate being, relative to the top plate, mounted movable in translation along a horizontal direction of movement (X) so that the dispenser can be configured in an open configuration if the intermediate passage is opposite the top passage; or in a closed configuration if the intermediate plate completely closes the top passage; the dispenser in the open configuration being configured to allow a flow of powder through the top passage and the intermediate passage.Figure to be published for the summary: Figure 1.

Description

Title of the invention: POWDER DISTRIBUTION SYSTEM FOR THREE-DIMENSIONAL PRINTING DOMAIN

[0001] The invention relates to the distribution of powder in three-dimensional printing systems, and in particular systems using binder deposition. STATE OF THE ART

[0002] Binder jetting (also known as "Binder Jetting") is a three-dimensional printing technique, also called an additive manufacturing technique, in which a binder is deposited in certain places in a layer of powder, the binder being subsequently rigidified.

[0003] It is common in this technique to use a sieve through which the powder flows before it is spread in the printing area and to implement after the hardening of the binder a sintering step which is a temperature increase of the object to densify it.

[0004] In the case of ceramic powders and certain inorganic powders, it is difficult to find powders that both flow well through the sieve (i.e., powders with high flowability) and react satisfactorily in the sintering step. For example, when the particle size of a powder increases, its flowability increases, but the reaction in the sintering step becomes less satisfactory.

[0005] There is therefore a need to improve solutions for manufacturing objects using additive manufacturing by binder deposition. EXPOSED

[0006] One aim of the present presentation is to propose a powder dispenser for additive manufacturing that is more efficient than in the prior art.

[0007] The objective is achieved by means of a powder dispenser for a three-dimensional printing device, the dispenser comprising:

[0008] - a horizontally arranged upper plate having an upper passage passing vertically through the upper plate,

[0009] - an intermediate plate arranged horizontally below the plate upper, the intermediate plate having an intermediate passage passing vertically through the intermediate plate,

[0010] the intermediate plate being, relative to the upper plate, mounted to move in translation along a horizontal direction of movement so that the distributor can be configured in an open configuration if the intermediate passage is opposite the upper passage; or in a closed configuration if the intermediate plate completely closes the upper passage; the distributor in the open configuration being configured to allow powder to flow through the upper passage and the intermediate passage.

[0011] Such a powder dispenser is advantageously and optionally complemented by the following various features, taken alone or in combination: - a lower plate arranged horizontally and fixed in relation to the upper plate, the intermediate plate being arranged between the lower plate and the upper plate, the lower plate having a lower passage crossing vertically through the lower plate, the lower passage and the upper passage being of the same dimensions and vertically aligned; - the upper passage has a dimension greater than or equal to 10 millimeters in a horizontal plane; - the intermediate plate has a stroke relative to the upper plate from an initial position to a final position, the distributor being in closed configuration if the intermediate plate is in the initial position, the distributor being in closed configuration if the intermediate plate is in the final position, and the distributor being in open configuration if the intermediate plate is in a rocking position located between the initial position and the final position; - the intermediate plate is configured to slide along the direction of travel in contact with a support plate, the support plate being the top plate or the bottom plate, the intermediate plate and the support plate comprising two guides and two grooves, each guide being configured to be inserted and move along the direction of travel in a respective groove; - each groove presents, in a plane transverse to the direction of movement, a first section, and each guide presents, in a plane transverse to the direction of movement, a second section whose shape is complementary to the first section; and - a spring configured to exert a constraint on the intermediate plate in the direction of movement relative to the upper plate so as to place the distributor in the closed configuration.

[0012] The presentation also relates to a powder distribution assembly for a three-dimensional printing device, the assembly comprising:

[0013] - a chassis,

[0014] - a hopper configured to receive and store manufacturing powder additive,

[0015] - a distributor such as has been presented so far, the upper plate being mounted fixed below the hopper,

[0016] - a conveyor configured to move, relative to the chassis, the hopper and the distributor according to the direction of movement, the assembly being configured to move the distributor from the closed configuration to the open configuration if the distributor is in a predetermined position.

[0017] Such an assembly is advantageously and optionally complemented by a locking piece configured to keep the intermediate plate immobile relative to the chassis if the distributor is in the predetermined position.

[0018] The presentation also relates to a three-dimensional printing device comprising a distribution assembly as just described.

[0019] The presentation finally relates to a powder distribution process, the process comprising the following steps:

[0020] - displacement of an intermediate plate relative to an upper plate according a horizontal direction of displacement, the intermediate plate being arranged horizontally below the upper plate, the horizontally arranged upper plate having an upper passage vertically through the upper plate, the intermediate plate having an intermediate passage vertically through the intermediate plate, the displacement of the intermediate plate being configured to go from a closed configuration in which the material of the intermediate plate completely covers the upper passage to an open configuration in which the intermediate passage is opposite the upper passage,

[0021] - flow of powder through the upper passage and the intermediate passage, and

[0022] - displacement of the intermediate plate relative to the upper plate for switch from open configuration to closed configuration. DESCRIPTION OF THE FIGURES

[0023] Other features and advantages will become apparent from the following description, which is purely illustrative and not limiting, and should be read in conjunction with the accompanying drawings on which:

[0024] [Fig.1] is a schematic representation of a three-dimensional printing device;

[0025] [Fig. 2] is a schematic representation of a hopper and a powder dispenser; and

[0026] Fig. 3, Fig. 4 and Fig. 5 are schematic representations of plates of a powder dispenser

[0027] Figures 6, 7, 8 and 9 are schematic representations of powder dispensers, and

[0028] [Fig. 10] is a schematic representation of a powder distribution process. DETAILED DESCRIPTION OF THE INVENTION Three-dimensional printing device

[0029] With reference to [Fig. 1], a three-dimensional printing (or additive manufacturing) device 1 comprises a fixed frame 4, also called a printer frame, which is rigidly fixed to the ground. The device 1 is shown during the fabrication of an object 20.

[0030] The device includes a hopper 7 configured to receive and store additive manufacturing powder, and a build tank 16 including a printing area 18. The build tank 16 is fixedly mounted on the frame 4. The hopper 7 is located vertically above the printing area 18.

[0031] The three-dimensional printing device is configured to distribute the powder from the top, i.e. the powder is placed above the printing area and it flows from top to bottom to be placed in the printing area.

[0032] The Z direction illustrated in [Fig. 1] corresponds to the vertical direction; it is oriented positively upwards. The hopper 7 is mounted to move relative to the frame 4 so that it can be moved translationally along a horizontal direction X. The device 1 comprises a movable frame 2 on which the hopper 7 is fixed. The device 1 further comprises a conveyor 10 configured to move the movable frame 2 and the hopper 7 along the X direction. A fixed portion of the conveyor 10 is fixedly mounted on the fixed frame 4, and a movable portion of the conveyor 10 is fixedly mounted on the movable frame 2. The hopper 7 can slide along the X direction relative to the fixed frame 4 along the conveyor 10. The hopper 7 can be positioned along the X direction via the conveyor 10.

[0033] The device 1 further comprises a binder deposition module configured to deposit binder at certain locations in the powder layer, and a lamp 22 whose radiation is configured to stiffen the binder once deposited on the powder bed. The binder deposition module is advantageously fixed to a conveyor 12 of a print head.

[0034] The lamp 22 is rigidly fixed to the movable frame 2 and the hopper 7, so that it can be driven by the conveyor 10. The lamp 22 is positioned vertically above the printing area. The lamp 22 and the hopper 7 have different positions along the X direction of travel. For two different positions of the movable frame 2 relative to the fixed frame 4, either the hopper 7 or the lamp 22 can be positioned opposite the printing area.

[0035] Powder dispenser for three-dimensional printing

[0036] The device 1 includes at the bottom of the hopper 7 a powder dispenser 9 which is fixedly mounted to the hopper 7.

[0037] With reference to [Fig. 2], the distributor 9 comprises an upper plate 26 and an intermediate plate 28, both of which are arranged horizontally. A horizontally oriented plate is understood here as a part whose vertical dimension along the Z direction is significantly smaller than the dimensions of the part along the horizontal X direction and the horizontal Y direction, also called the transverse direction. The transverse direction Y is orthogonal to the X direction of movement and the vertical direction Y. The vertical dimension of a horizontally oriented plate is, for example, 10 times smaller than its dimensions along the horizontal X and Y directions.

[0038] Fig. 3 schematically illustrates a representation in a horizontal plane of the upper plate 26.

[0039] The upper plate 26 may have a rectangular shape in horizontal section and oriented along the X and Y directions.

[0040] The upper plate may have a length along the transverse direction Y greater than or equal to 150 millimeters and less than or equal to 250 millimeters and preferably greater than or equal to 175 millimeters and less than or equal to 225 millimeters, for example equal to 197 millimeters.

[0041] The upper plate may have a depth along the direction of displacement X greater than or equal to 20 millimeters and less than or equal to 90 millimeters and preferably greater than or equal to 40 millimeters and less than or equal to 70 millimeters, for example equal to 55 millimeters.

[0042] The upper plate 26 has an upper passage 27 which passes vertically through the upper plate. The upper passage 27 passes completely through the upper plate 26 from top to bottom. The upper passage 27 opens into a lower face of the upper plate 26 and opens into a upper face of the upper plate 26.

[0043] The upper passage 27 may have a rectangular shape in horizontal section and oriented along the X and Y directions.

[0044] The upper passage 27 may have a length Ls along the transverse direction Y greater than or equal to 150 millimeters and less than or equal to 210 millimeters and preferably greater than or equal to 165 millimeters and less than or equal to 185 millimeters, for example equal to 177 millimeters.

[0045] The upper passage 27 may have a depth Ps along the direction of displacement X greater than or equal to 5 millimeters and less than or equal to 25 millimeters and preferably greater than or equal to 10 millimeters and less than or equal to 20 millimeters, for example equal to 13 millimeters.

[0046] The upper passage can be centered with respect to the upper plate.

[0047] Figure [Fig. 4] schematically illustrates a cross-section in a horizontal plane of the intermediate plate 28.

[0048] The intermediate plate 28 may have a rectangular shape in horizontal section and be oriented along the X and Y directions.

[0049] The intermediate plate 28 may have a length along the transverse direction Y greater than or equal to 150 millimeters and less than or equal to 250 millimeters and preferably greater than or equal to 175 millimeters and less than or equal to 225 millimeters, for example equal to 197 millimeters.

[0050] The intermediate plate 28 can have a depth along the direction of displacement X greater than or equal to 20 millimeters and less than or equal to 90 millimeters and preferably greater than or equal to 40 millimeters and less than or equal to 70 millimeters, for example equal to 55 millimeters.

[0051] The intermediate plate 28 has an intermediate passage 29 which passes vertically through the upper plate. The intermediate passage 29 passes completely through the intermediate plate 28 from top to bottom. The intermediate passage 29 opens into a lower face of the intermediate plate 28 and opens into a upper face of the intermediate plate 28.

[0052] The intermediate passage 29 may have a rectangular shape in horizontal section and oriented along the X and Y directions.

[0053] The intermediate passage 29 may have a length Li along the transverse direction Y greater than or equal to 150 millimeters and less than or equal to 210 millimeters, and preferably greater than or equal to 165 millimeters and less than or equal to 185 millimeters, for example, equal to 177 millimeters. Advantageously, the length Li is equal to the length Ls.

[0054] The intermediate passage 29 may have a depth Pi along the direction of movement X greater than or equal to 5 millimeters and less than or equal to 25 millimeters, and preferably greater than or equal to 10 millimeters and less than or equal to 20 millimeters, for example, equal to 13 millimeters. Advantageously, the depth Pi is equal to the depth Ps. However, it is possible that the depths Pi and Ps are different.

[0055] The intermediate passage 29 can be centered with respect to the intermediate plate 28.

[0056] The intermediate plate 28 comprises on either side of the intermediate passage 29 in the direction of displacement X, a solid upstream zone 51 and a solid downstream zone 53. They are defined with respect to the orientation of the direction X, which runs from the solid upstream zone 51 to the solid downstream zone 53. The upstream and downstream zones are directly adjacent to the intermediate passage 29 and have no passage or opening vertically crossing the intermediate plate. The upstream zone 51 has a The upstream depth 52 is along the direction of movement X. The downstream zone 53 has a downstream depth 50 along the direction of movement X. The upstream depth 52 and the downstream depth 50 can be chosen to be greater than or equal to the depth Ps.

[0057] The intermediate plate 28 is mounted to move in translation relative to the upper plate 26 along the horizontal direction of movement X.

[0058] Different embodiments of the distributor 9 allow the movable character of the intermediate plate 28 to be achieved in relation to the upper plate 26.

[0059] In a first configuration, the intermediate plate 28 may have two grooves 36 and 38 elongated along the direction of movement X. The grooves 36 and 38 may be located on either side of the intermediate passage 29 along the transverse direction Y. In other words, along the transverse direction Y, the intermediate passage 28 is located between the groove 36 on one side and the groove 38 on the other. Internal walls of the intermediate plate 28 parallel to the direction X may define the grooves 36 and 38. The grooves 36 and 38 open outwards into the upper face of the intermediate plate 28, that is, towards the upper plate 26. The grooves 36 and 38 may optionally open outwards into the lower face of the intermediate plate 28.

[0060] According to the first mode, the upper plate 26 may have two guides 32 and 34 elongated along the direction of movement X. The guides 32 and 34 may be located on either side of the upper passage 27 along the transverse direction Y. In other words, along the transverse direction Y, the upper passage 27 is located between the guide 32 on one side and the guide 36 on the other. External walls of the upper plate 26 parallel to the direction X may define the guides 32 and 34. The guides 32 and 34 project outwards from the underside of the upper plate 26, that is, towards the side of the intermediate plate 28.

[0061] Each guide 32 34 is configured to be inserted into one of the grooves 36 and 38 and to move along the direction of travel X in the groove. In particular, guide 32 can be inserted into groove 36 and guide 34 into groove 38.

[0062] The dimension of a groove along the transverse direction Y is slightly greater than the dimension of a guide along this same direction to allow movement but requiring that the guides move along the direction of displacement X.

[0063] The dimension of a groove along the direction of displacement X is significantly greater than the dimension of a guide along this same direction to define a non-zero stroke of the intermediate plate 28 relative to the upper plate 26.

[0064] In a first variant of the first mode, the distributor 9 may comprise a lower plate 30 arranged horizontally and fixedly mounted relative to the upper plate, the intermediate plate being arranged between the lower plate and the upper plate. [Fig. 2] illustrates this situation.

[0065] Figure 5 schematically illustrates a cross-section in a horizontal plane of the plate less than 30.

[0066] The lower plate 30 may have a rectangular shape in horizontal section and be oriented along the X and Y directions.

[0067] The lower plate 30 may have a length along the transverse direction Y greater than or equal to 150 millimeters and less than or equal to 250 millimeters and preferably greater than or equal to 175 millimeters and less than or equal to 225 millimeters, for example equal to 197 millimeters.

[0068] The lower plate 30 can have a depth along the direction of displacement X greater than or equal to 20 millimeters and less than or equal to 90 millimeters and preferably greater than or equal to 40 millimeters and less than or equal to 70 millimeters, for example equal to 55 millimeters.

[0069] The lower plate 30 has a lower passage 31 which crosses vertically through the lower plate 30. The lower passage 31 crosses the lower plate 30 from top to bottom. The lower passage 30 opens into a lower face of the lower plate 30 and opens into a upper face of the lower plate 30.

[0070] The lower passage 31 has the same shape and orientation as the upper passage 27. The lower plate 30 is fixed relative to the upper plate 28 so that the lower and upper passages are vertically aligned. This means that the lower and upper passages have identical positions along the vertical Z direction. In other words, the internal walls of the lower and upper plates that define the lower and upper passages are located in the same horizontal positions along the X and Y directions.

[0071] In the first variant of the first mode, the grooves 36 and 38 are through and the guides 32 and 34 have a vertical thickness greater than the vertical thickness of the intermediate plate 28. These thicknesses are chosen to be close enough to limit the bulk while leaving sufficient mechanical play so as not to jam the intermediate plate between the lower plate and the upper plate.

[0072] In a second variant of the first mode, each groove 36, 38 has, in a plane transverse to the direction of movement X, a first section, and each guide 32, 34 has, in a plane transverse to the direction of movement, a second section with a shape complementary to the first section. The shapes are not exactly complementary to allow sufficient mechanical clearance so as not to jam the intermediate plate in the upper plate. This second variant is illustrated in [Fig. 6]. Advantageously, the shape of the sections is flared downwards, or in other words, the section has a neck below which the section extends so that the dimension of the section along the transverse direction Y increases to as one descends vertically. Grooves 36 and 38 can optionally be through grooves.

[0073] In a third embodiment of the first mode, the distributor 9 includes a retention system for the intermediate plate 28 configured to hold the intermediate plate below the upper plate 26. For example, the retention system includes upward-pointing fins that are part of the intermediate plate, the upward-pointing fins projecting upwards from the intermediate plate, a portion of the fins being located vertically above the material of the upper plate 26. For example, the retention system includes downward-pointing fins that are part of the upper plate 26, a portion of the downward-pointing fins being located vertically below the material of the intermediate plate 28. These fins do not impede the translational movement along the X direction of the intermediate plate relative to the upper plate.

[0074] In a second mode, the upper plate 27 has the two grooves, while the intermediate plate includes the guides. In a first variant of the second mode, the distributor includes a lower plate as previously described. In a second variant of the second mode, each groove has a first section in a plane transverse to the direction of movement X, and each guide has a second section in a plane transverse to the direction of movement, the shape of which is complementary to the first section. The shapes are not exactly complementary to allow sufficient mechanical clearance so as not to jam the intermediate plate in the upper plate.Advantageously, the shape of the sections is flared upwards, or in other words, the section has a neck above which the section extends so that the dimension of the section along the transverse Y direction increases as one ascends vertically. The grooves can optionally be through grooves.

[0075] In a third configuration, the distributor comprises a lower plate as previously described. The intermediate plate 28 has two grooves as previously described, and the lower plate 30 has two guides as previously described. The grooves open outwards on the lower face of the intermediate plate 28, i.e., on the side of the lower plate 30. Optionally, the grooves may open outwards on the upper face of the intermediate plate 28. The guides project outwards from the upper face of the lower plate 30, i.e., on the side of the intermediate plate 28.

[0076] In a variant of the third mode, each groove has a first section in a plane transverse to the direction of movement X, and each guide has a second section in a plane transverse to the direction of movement, of the form complementary to the first section. Advantageously, the shape of the sections flares upwards, or in other words, the section has a neck above which it extends, so that the dimension of the section along the transverse Y direction increases vertically. The grooves can optionally be through grooves.

[0077] In a fourth embodiment, the distributor comprises a lower plate as previously described. The intermediate plate 28 has two guides as previously described, and the lower plate 30 has two grooves as previously described. The grooves open outwards on the upper face of the lower plate 30, i.e., on the side of the intermediate plate 28. Optionally, the grooves may open outwards on the lower face of the lower plate 30. The guides project outwards from the lower face of the intermediate plate 28, i.e., on the side of the lower plate 30.

[0078] In a variant of the third mode, each groove has a first section in a plane transverse to the direction of movement X, and each guide has a second section in a plane transverse to the direction of movement, the shape of which is complementary to the first section. Advantageously, the shape of the sections flares downwards, or in other words, the section has a neck below which the section extends, so that the dimension of the section along the transverse direction Y increases as one descends vertically. The grooves may optionally be through grooves.

[0079] In relation to these four modes, a support plate can be defined as either the upper or lower plate. The support plate is the plate that includes the guides or has the grooves. The intermediate plate and the support plate together comprise the two guides and the two grooves, each guide being configured to be inserted and move along the direction of travel in one of the grooves.

[0080] The link between the intermediate plate 28 and the upper plate 26 allowing the intermediate plate 28 to be moved in translation relative to the upper plate 26 can be achieved by other means such as ball bearings or toothed wheels which collaborate with toothed belts.

[0081] The intermediate plate 28 has a stroke relative to the upper plate 26 which is defined between an initial position and a final position. The initial or final position is reached when the guide comes to rest against one of the ends of the groove.

[0082] As the intermediate plate 28 is mounted to move in translation relative to the upper plate 26, the distributor 9 can be configured in the following two configurations: - an open configuration if the intermediate passage 29 is opposite the upper passage 27; and

[0083] - a closed configuration if the material of the intermediate plate closes completely the overpass 27.

[0084] Figure 8 illustrates the open configuration and Figures 7 and 9 illustrate the closed configuration.

[0085] The open configuration corresponds to the situation (or situations) where the intermediate passage 29 is aligned with the upper passage 27, that is, where the overlap between a vertical projection of the upper passage 27 and a vertical projection of the intermediate passage 29 is maximized. The open configuration corresponds to the position of the intermediate plate 28 relative to the upper plate 26 that maximizes the vertical overlap between the upper passage 27 and the intermediate passage 29.

[0086] When the intermediate passage 29 and the upper passage 27 have the same length and depth, i.e., when Li=Ls and Pi=Ps, the open configuration corresponds to a particular position of the intermediate plate 28 relative to the upper plate 26; this is the position where the intermediate passage 29 and the upper passage 27 are vertically aligned. This means that the intermediate passage 29 and the upper passage 27 have identical positions along the horizontal X and Y directions.

[0087] When the intermediate passage 29 and the upper passage 27 have the same length but a different depth, i.e. when Li=Ls and Pi^Ps, the open configuration corresponds to a plurality of positions of the intermediate plate 28 with respect to the upper plate 26. These are the positions where the vertical projection of the shallowest passage is included in the vertical projection of the deepest passage.

[0088] The closed configuration corresponds to the situation(s) where the material of the intermediate plate completely closes the upper passage 27, that is, the overlap between the vertical projection of the upper passage 27 and the vertical projection of the intermediate passage 29 is zero. The closed configuration corresponds to the positions of the intermediate plate 28 relative to the upper plate 26 that minimize the vertical overlap between the upper passage 27 and the intermediate passage 29.

[0089] The closed configuration corresponds, for example, to cases where the upstream solid zone 51 or the downstream solid zone 53 is vertically above the overpass 27. [Fig. 7] illustrates the case where the upstream full zone 51 is vertical over the overpass 27 and [Fig.9] illustrates the case where the downstream full zone 53 is vertical over the overpass 27.

[0090] The distributor in its open configuration allows powder to flow through the upper and intermediate passages. The distributor's intermediate plate acts as a trap for the powder. Such a trap can advantageously replace a sieve in a powder distribution assembly, particularly because it can have significantly larger dimensions than the orifices of a sieve, thus ensuring good powder flow regardless of its particle size.

[0091] Advantageously, the intermediate plate 28 has a stroke relative to the upper plate 26 from an initial position to a final position, the distributor being:

[0092] - in closed configuration if the intermediate plate is in the initial position,

[0093] - in closed configuration if the intermediate plate is in the final position, and

[0094] - in open configuration if the intermediate plate is in a tilting position located between the initial position and the final position.

[0095] The initial position, the final position and the tipping position are relative positions of the intermediate plate 28 with respect to the upper plate 26.

[0096] Figures 7, 8 and 9 illustrate this advantageous case.

[0097] The initial position can be defined when the intermediate plate 28 has a maximum value of the coordinate along the X direction relative to the upper plate 26, and the final position can be defined when the intermediate plate 28 has a minimum value of the coordinate along the X direction relative to the upper plate 26. In this case, the upstream solid area 51 is vertically above the overpass 27 for the initial position and the downstream solid area 53 is vertically above the overpass 27 for the final position.

[0098] Optionally, the distributor 9 includes a spring 44 configured to exert a constraint on the intermediate plate 28 in the direction of movement X relative to the upper plate 26 so as to place the distributor in the closed configuration.

[0099] The spring 44 can, for example, be arranged parallel to the X direction on one of the edges of the intermediate and upper plates that is parallel to the X direction. The upper plate 26 can include a support 40 to receive a first end of the spring, and the intermediate plate 28 can include a support 42 to receive a second end of the spring. The spring can be arranged to work in compression or extension depending on whether it exerts a force that moves the supports 40 and 42 apart or together. For example, an arrangement can be defined in which the spring exerts a stress on the intermediate plate in the direction of an initial position. relative to the upper plate 26 corresponding to a maximum value of the coordinate along the X direction.

[0100] The distributor 9 may include several springs that define a constraint in the same direction and along the same axis. For example, the distributor 9 may include two springs 44 arranged on either side of the intermediate plate 28 with respect to the transverse direction Y.

[0101] Figure 7 illustrates the situation where two springs 44 exert a force in the direction of the approach of the support 40 towards the support 42. The force exerted by the springs on the intermediate plate 28 is directed in the direction of orientation of the X direction and the force exerted by the springs on the upper plate 26 is directed in the opposite direction to the orientation of the X direction. In this case, the springs exert a restoring force on the intermediate plate 28 towards its initial position corresponding to a maximum value of its coordinate along the X direction.

[0102] A powder distribution assembly 3 can be defined for a three-dimensional printing device, the assembly comprising the fixed frame 4, the hopper 7, the distributor 9 as previously shown and the conveyor 10.

[0103] The assembly 3 may advantageously include transducers arranged in contact with the hopper 7. The transducers are configured to generate ultrasonic waves capable of setting in motion the powder contained in the hopper.

[0104] Assembly 3 is configured to move distributor 9 from the closed configuration to the open configuration if distributor 9 is in a predetermined position.

[0105] The predetermined position corresponds to a preferred position for delivering powder, such as when the dispenser is located directly above the printing area.

[0106] Assembly 3 may, for example, include a motor for moving the intermediate plate 28 relative to the upper plate 26, which is triggered when the distributor 9 reaches the predetermined position. Assembly 3 may include a distributor locating system configured to generate a signal when the distributor 9 reaches the predetermined position, the signal being transmitted to the motor to move the intermediate plate 28. Such a locating system may include an electromagnetic radiation sensor or a magnetic sensor configured to measure a signal that changes when the distributor 9 reaches the predetermined position.

[0107] Alternatively, the distributor 9 may include a cord 46 having an invariable length, that is to say, a cord 46 that is not elastic or whose elasticity is negligible. For example, the cord has a relative extension of less than 0.1% of its length.

[0108] Such a cord can be attached on one side to the fixed frame 4 and on the other side to the intermediate plate 28, for example to an attachment ring 48 on the intermediate plate. The length of the cord is adapted to keep it taut when the distributor 9 moves, for example in the direction of orientation X, and approaches the predetermined position. Once taut, the cord holds the intermediate plate 28 and moves the intermediate plate 28 relative to the upper plate 26. This allows the distributor to be placed in the open configuration when the distributor 9 reaches the predetermined position. The assembly 3 can include a bracket 5 fixed to the fixed frame 4. The cord can be arranged to pass through the bracket so that the cord exits the bracket 5 at a height equal to or close to the height at which the cord is attached to the intermediate plate 28.In this way, when taut, the cord exerts a force on the intermediate plate 28 in the horizontal direction X, and not in an oblique direction which has a non-zero vertical component. Such a force in an oblique direction would exert undesired stresses on the distributor 9.

[0109] Alternatively, the assembly 3 may include a pusher configured to abut against a portion of the intermediate plate 28. Such a pusher is attached to the fixed frame 4. The pusher may be configured to press against one end of the intermediate plate 28 in the direction of travel X, for example, the end of the intermediate plate in the direction of travel X. The intermediate plate 28 may include a stop that projects from the plate and defines a contact surface against which the pusher abuts. The contact surface is orthogonal to the direction of travel X. The surface may be oriented in the direction of travel X.

[0110] When the distributor 9 moves, for example in the direction of travel X, and approaches the predetermined position, the pusher comes into contact with the intermediate plate 28, for example against the end of the intermediate plate in the direction of travel X, or against a stop on the plate. The pusher then holds the intermediate plate 28 and moves the intermediate plate 28 relative to the upper plate 26. This allows the distributor to be placed in the open position when the distributor 9 reaches the predetermined position.

[0111] In the last two examples, the cord and the pusher act as a blocking piece 45 configured to keep the intermediate plate 28 immobile relative to the fixed chassis 4 if the distributor 9 is in the predetermined position.

[0112] Finally, we can define a three-dimensional printing device comprising a powder distribution assembly such as we have just described. Powder dispensing process

[0113] A distributor such as has been presented allows a process, designated by the letter P, to be implemented for distributing additive manufacturing powder.

[0114] An implementation of the process is now described in relation to [Fig. 10].

[0115] During a step E2, the intermediate plate is moved relative to the plate The distributor moves from the closed position to the open position along the horizontal X direction of travel. This movement changes the distributor from the closed position to the open position.

[0116] During a step E3, a powder flow is generated through the upper passage and the intermediate passage.

[0117] During a step E4, the intermediate plate is moved relative to the upper plate along the horizontal X direction of movement to move the distributor from the closed configuration to the open configuration.

[0118] As mentioned, the intermediate plate of the dispenser acts as a powder trap. Opening the trap allows powder to be supplied, for example, to the printing area. Closing the trap allows the manufacturing process to continue without the risk of spilling powder.

[0119] A distribution set such as has been presented allows steps to be added to process P.

[0120] In a first step E1, the conveyor 10 moves the hopper 7 and the distributor 9 towards the printing area. The hopper 7 contains additive manufacturing powder to be spread in the printing area. The conveyor 10 moves the hopper 7 and the distributor 9 in a translational motion along the direction of travel X. The movement is in the orientation direction of X. The distributor 9 is in the closed configuration at this stage. More precisely, the intermediate plate 28 is in its initial position so that the upstream area 51 completely closes the upper passage 27. If the distributor includes a spring 44, then this spring maintains the intermediate plate 28 in its initial position. Figure 7 illustrates this situation.

[0121] During the first step 11, the distributor approaches its predetermined position, which is advantageously directly above the printing area. If the assembly includes a locking piece, the locking piece holds the intermediate plate 28 stationary relative to the fixed frame 4. The intermediate passage 29 approaches the upper passage 27. If the distributor includes a spring 44, then the spring is gradually deformed.

[0122] During the second step E2, the distributor reaches its predetermined position and the intermediate plate is positioned relative to the upper plate 26 so as to place the distributor in the open configuration. If the assembly includes a motor and a locating system, then the blocking piece generates a signal that triggers the motor so as to move the intermediate plate 28. If the assembly The distributor includes a locking piece, which continues to hold the intermediate plate 28 stationary relative to the fixed frame 4. In both cases, the intermediate passage 29 is positioned opposite the upper passage 27. The intermediate plate reaches a tilting position relative to the upper plate 26. If the distributor includes a spring 44, then this spring is deformed and exerts a restoring force on the intermediate plate towards its initial position. The restoring force is balanced by the force exerted by the locking piece on the intermediate plate 28. Figure 8 illustrates this situation. The conveyor keeps the hopper 7 and the distributor 9 stationary.

[0123] During the third step E3, a powder flow is generated through the upper and intermediate passages. If the assembly includes transducers, the transducers agitate the powder in the hopper 7 to cause it to flow towards the dispenser. The powder passes through the dispenser and reaches the printing area 18. Figure 1 illustrates a powder flow 24 exiting the dispenser 9 and arriving at the printing area. The transducers are then switched off.

[0124] During additive manufacturing, the powder is then spread, and then in the case of manufacturing by binder deposition, the binder is deposited.

[0125] During the fourth step E4, the intermediate plate is positioned relative to the upper plate 26 so as to place the distributor in the closed position. If the assembly includes a motor and a locating system, then the locking piece can generate a new signal that triggers the motor to move the intermediate plate 28. The intermediate plate 28 closes the upper passage 27. Either the upstream zone 51 or the downstream zone 53 closes the upper passage 27. If the assembly includes a locking piece, the conveyor restarts the hopper 7 and the distributor 9 in the direction of travel X and according to the orientation of the direction X. The locking piece continues to hold the intermediate plate 28 stationary relative to the fixed frame 4. The downstream zone 53 closes the upper passage 27. If the distributor includes a spring 44, then the spring is deformed even further.The intermediate plate can then reach its final position relative to the upper plate 26. [Fig.9] illustrates this situation. In all cases, the intermediate plate 28 closes the upper passage 27.

[0126] In a fifth step E5, the deposited powder is solidified. For example, in the case of manufacturing by binder deposition, the lamp 24 is placed opposite the printing area and illuminates the printing area. Advantageously, this can be achieved by activating the conveyor 10 so that it sets the distributor 9 in motion from its predetermined position along the direction of travel X and with the orientation of the direction X.

[0127] During a sixth step E6, the conveyor returns the hopper 7 and the distributor 9 to their initial position. The conveyor moves the hopper 7 and the distributor 9 according to the The direction of movement X is opposite to the direction of orientation of the X direction. If the assembly includes a locking piece, the locking piece exerts a decreasing force on the intermediate plate 28. If the distributor 9 includes a spring 44, then this gradually moves the intermediate plate from its final position to its initial position.

[0128] At the end of the sixth step E6, the distribution assembly is ready to carry out a new iteration of the powder distribution process by again performing steps E1, E2, E3, E4, E5 and E6.

[0129] The processes as described above can advantageously be applied to ceramic powders or, more generally, to powders exhibiting low flowability, that is, a low capacity for the powder to flow smoothly. The flowability of a powder can be quantified by the so-called "flow function" parameter (also known as the flow function, abbreviated as ffc). The ffc parameter is measured using a powder rheometer such as the 'FT4' instrument from 'Freeman Technology'. The ffc parameter corresponds to the ratio of the normal stress to the shear stress that sets the powder in motion. The lower the ffc parameter, the lower the flowability of the powder.The processes as presented can advantageously be applied to powders which have an ffc parameter less than or equal to 3, and even more advantageously to powders which have an ffc parameter less than or equal to 2.

Claims

Demands

1. Powder dispenser (9) for a three-dimensional printing device (1), the dispenser (9) comprising: - an upper plate (26) arranged horizontally and having an upper passage (27) passing vertically through the upper plate, - an intermediate plate (28) arranged horizontally below the upper plate, the intermediate plate having an intermediate passage (29) passing vertically through the intermediate plate, the intermediate plate being, relative to the upper plate, mounted to move in translation along a horizontal direction of movement (X) so that the dispenser can be configured in an open configuration if the intermediate passage is opposite the upper passage; or in a closed configuration if the intermediate plate completely closes the upper passage;the distributor in open configuration being configured to allow powder to flow through the upper passage and the intermediate passage.

2. Distributor according to claim 1 comprising a lower plate (30) arranged horizontally and fixedly mounted relative to the upper plate, the intermediate plate being arranged between the lower plate and the upper plate, the lower plate having a lower passage (31) passing vertically through the lower plate, the lower passage and the upper passage being of the same dimensions and vertically aligned.

3. Distributor according to any one of claims 1 and 2 wherein the upper passage has in a horizontal plane a dimension greater than or equal to 10 millimeters.

4. Distributor according to any one of claims 1 to 3 wherein the intermediate plate has a stroke relative to the upper plate from an initial position to a final position, the distributor being: - in the closed configuration if the intermediate plate is in the initial position, - in the closed configuration if the intermediate plate is in the final position, and - in open configuration if the intermediate plate is in a rocker position located between the initial position and the final position.

5. Distributor according to any one of claims 1 to 4 wherein the intermediate plate is configured to slide in the direction of travel in contact with a support plate, the support plate being the upper plate or the lower plate, the intermediate plate and the support plate comprising two guides (32, 34) and two grooves (36, 38), each guide being configured to be inserted and move in the direction of travel in a respective groove.

6. Distributor according to claim 5 in which each groove has in a plane transverse to the direction of movement a first section and each guide has in a plane transverse to the direction of movement a second section of shape complementary to the first section.

7. Distributor according to any one of claims 1 to 6 comprising a spring (44) configured to exert a constraint on the intermediate plate in the direction of movement relative to the upper plate so as to place the distributor in the closed configuration.

8. Powder distribution assembly (3) for a three-dimensional printing device, the assembly comprising: - a frame (4), - a hopper (7) configured to receive and retain additive manufacturing powder, - a dispenser (9) according to any one of claims 1 to 7, the upper plate being fixedly mounted below the hopper, - a conveyor (10) configured to move, relative to the frame, the hopper and the dispenser in the direction of travel, the assembly being configured to move the dispenser from the closed configuration to the open configuration if the dispenser is in a predetermined position.

9. Assembly according to claim 8 comprising a locking piece (45) configured to keep the intermediate plate immobile relative to the chassis if the distributor is in the predetermined position.

10. Three-dimensional printing device (1) comprising a distribution assembly according to any one of claims 8 to 9.

11. A powder distribution method (P), the method comprising the following steps: - (E2) displacement of an intermediate plate (28) relative to an upper plate (26) along a horizontal direction of displacement, the intermediate plate being arranged horizontally below the upper plate, the horizontally arranged upper plate having an upper passage (27) passing vertically through the upper plate, the intermediate plate having an intermediate passage (29) passing vertically through the intermediate plate, the displacement of the intermediate plate being configured to pass from a closed configuration in which the material of the intermediate plate completely covers the upper passage to an open configuration in which the intermediate passage is opposite the upper passage, - (E3) flow of powder through the upper passage and the intermediate passage, and - (E4) displacement of the intermediate plate relative to the upper plate to go from the open configuration to the closed configuration.

Images