THREE-DIMENSIONAL BINDER SPRAY PRINTING MACHINE

Abstract

THREE-DIMENSIONAL PRINTING MACHINE BY BINDER PROJECTION The invention relates to a three-dimensional printing machine comprising: - a powder reservoir (17) configured to receive a powdered material, - a build tray (15) adapted to receive a part manufactured by said printing machine, - a movable print head, - a dispensing device configured to form a layer of powdered material within said build tray (15), - a printing chamber (4) configured to receive said movable print head and said dispensing device, said build tray (15) opening into said printing chamber (4), - means for moving said movable print head and said dispensing device, said means for moving said printing chamber (4). Figure for the abstract: Figure 1

Description

Title of the invention: THREE-DIMENSIONAL PRINTING MACHINE BY BINDER SPRAYING Technical field of the invention

[0001] The present invention relates to the field of 3D printing or additive manufacturing. The invention relates more particularly to a three-dimensional printing machine using binder jetting for manufacturing metal parts. Technological background

[0002] Additive manufacturing makes it possible to print three-dimensional parts without human intervention or specific tooling from a digital file on which the three-dimensional object has been modeled in a set of two-dimensional layers.

[0003] The binder jetting three-dimensional printing technique consists of jetting a liquid adhesive binder onto thin layers of powder deposited from a powder reservoir. The binder is jetting through a print head, which progressively forms an additional layer of the object to be manufactured.

[0004] Document WO2022 / 186704 describes, for example, a 3D printing machine comprising a chamber with a vertically movable platform supporting a building material. The 3D printing machine also includes a print head for depositing a binder onto the building material, and a spreading device for spreading the building material onto a building surface.

[0005] The three-dimensional printing technique of binder jetting onto a powder bed requires the simultaneous control of numerous parameters to enable the production of a part of satisfactory quality. The distribution and nature of the powder, as well as the properties of the binder, are particularly critical. Furthermore, the metal powders used to manufacture metal parts are delicate to handle and necessitate the implementation of specific health precautions.

[0006] The invention aims to overcome these drawbacks. Objectives of the invention

[0007] The invention aims to provide, in at least one embodiment, a three-dimensional printing machine which is easy to implement and has excellent ergonomics.

[0008] The invention also aims to provide, in at least one embodiment, a three-dimensional printing machine which is, in general, simple to use, modular and particularly reliable.

[0009] The invention also aims to provide, in at least one embodiment, a three-dimensional printing machine that makes it possible to manufacture parts of excellent quality. Description of the invention

[0010] To this end, the invention relates to a three-dimensional printing machine comprising:

[0011] - a first container, called a powder reservoir, configured to be able to receive a powdery material,

[0012] - a second container, called a construction container, adapted to be able to receive a part manufactured by said printing machine,

[0013] - a movable print head configured to be able to project a composition liquid hardens sand, called binder, towards said construction tray.

[0014] - a distribution device for said powdered material configured to be able to to form, from said powder reservoir, at least one layer of said powdered material within said construction tray,

[0015] characterized in that it further comprises:

[0016] - a printing enclosure comprising a base and a plurality of walls, said printing chamber being configured to be able to receive said movable print head and said distribution device for said powdered material, said build tray opening into said printing chamber,

[0017] - means for moving said movable print head within said printing enclosure,

[0018] - means for moving said material distribution device powdery within said printing chamber,

[0019] said means of moving said print head and said distribution device being disposed outside said printing enclosure.

[0020] Advantageously and according to the invention, said means for moving said print head and said distribution device comprise at least one translational guide device and at least one transmission device. Each transmission device may, in particular, be selected from the group consisting of mechanical cable and / or belt drives, rack and pinion type mechanical drives, and ball screws. Advantageously and according to the invention, said means for moving said print head and said distribution device comprise at least two carriages movable in translation along at least one longitudinal direction of movement, at least one carriage being fixed in translation with said print head and at least one carriage being fixed in translation with said distribution device. Advantageously and according to the invention, said means for moving said print head comprise at least a translational guidance device along at least one longitudinal direction of movement. Advantageously, and according to the invention, said means for moving said distribution device comprise at least one translational guidance device along said longitudinal direction of movement.

[0021] Advantageously and according to the invention, said means of moving said print head and said means of moving said distribution device further each comprise at least one transmission device coupled to a motor so as to be able to drive in translation said at least one guide device.

[0022] Advantageously, and according to the invention, the walls of said printing chamber comprise two main side walls, each provided with at least one longitudinal through groove configured to allow translational movement of said printing head guide device and of said printing head guide device, including said carriage connected to said printing head and said carriage connected to said dispensing device. Advantageously, and according to the invention, each longitudinal through groove of said printing chamber is equipped with a sealing device (at least partial) against the powdered material (without preventing air circulation through each longitudinal groove).Advantageously, and according to the invention, each longitudinal groove through said printing chamber is equipped with brushes, flexible seals, or any other device for containing said powdered material inside said printing chamber.

[0023] Advantageously and according to the invention, said means for moving said movable print head comprise two translational guidance devices, in particular two movable carriages, a first translational guidance device being configured to be able to be driven in translation along a first longitudinal direction of movement and a second translational guidance device being configured to be able to be driven in translation along a second longitudinal direction of movement, said first longitudinal direction of movement and said second longitudinal direction of movement being parallel to each other.

[0024] Advantageously and according to the invention, said means of movement of said distribution device comprise two translational guidance devices, in particular two mobile carriages, a third translational guidance device being configured to be able to be driven in translation along a first longitudinal direction of movement and a fourth translational guidance device being configured to be able to be driven in translation along a second longitudinal direction of movement, said first longitudinal direction of movement and said second longitudinal direction of movement being parallel to each other.

[0025] Each carriage can be guided in translation in different ways. Advantageously, and according to the invention, each translational guidance device is a movable carriage mounted on a rail. Two carriages can be mounted on the same guide rail.

[0026] Advantageously, and according to the invention, the means for moving the print head and the dispensing device comprise a first motor driving a first rotor connected at each of its longitudinal ends to a pulley, and a second motor driving a second rotor connected at each of its longitudinal ends to a pulley. The first rotor connects the two guiding devices, in particular two movable carriages attached to the print head, and the second rotor connects the two guiding devices, in particular two movable carriages attached to the powdered material dispensing device. This allows for more precise and reliable movement of the print head and the powdered material dispensing device.

[0027] Advantageously and according to the invention, said three-dimensional printing machine further comprises an electronic unit for defining a command to be applied to said means of movement of said printing head and said distribution device and a human / machine interface configured to allow a user to define operating parameters of said three-dimensional printing machine.

[0028] Advantageously and according to the invention, said powder reservoir and said construction tray are removable and said printing machine includes conveying wheels for said powder reservoir and said construction tray.

[0029] Advantageously and according to the invention, said three-dimensional printing machine includes a lifting platform for said powder tank and said build tray, configured to be able to move said powder tank and said build tray between at least one lower position, in which said powder tank and said build tray are substantially at the level of said conveyor wheels, and at least one upper position in which said powder tank and said build tray open into said printing chamber.

[0030] Advantageously and according to the invention, said three-dimensional printing machine includes a reservoir of said binder.

[0031] A three-dimensional printing machine according to the invention can be configured to manufacture parts made of various materials, including metals, ceramics (including glasses), polymers, or composites. Thus, the powdered material is chosen from the group consisting of metal powders, ceramic powders (such as silicon carbide SiC, aluminum nitride AIN, alumina or alumina oxide Al₂O₃, zirconium dioxide or zirconia ZrO₂, or (also hydroxyapatite), polymer powders, their composites and their mixtures. Advantageously and according to the invention, said powdered material is chosen from the group formed by metallic powders.

[0032] Advantageously and according to the invention, said powdered material selected from the group consisting of metallic powders has a particle size between 0.5 µm and 5 µm. Advantageously and according to the invention, said metallic powders are selected from the group consisting of metals and their alloys, and are in particular selected from the group consisting of titanium, chromium, manganese, vanadium, iron, steels, copper, zinc, nickel, zirconium, palladium, silver, platinum, gold and mixtures thereof.

[0033] The distribution device for said powdered material is configured to be able to form, on a construction surface of the construction tray, a layer of said powdered material having a thickness between 10 pm and 100 pm, in particular between 30 pm and 60 pm.

[0034] The device for distributing said powdered material may also be referred to as a powder spreading arm or compaction device. It comprises at least one rotating roller or a powder spreading blade. The device for distributing said powdered material makes it possible to prepare a powder bed having an optimal density by compaction between the rotating roller (or a spreading blade) and a build surface within said build tray.

[0035] The binder projected by the print head can in particular be chosen from the group consisting of thermosetting polymers (or "resins") and photopolymers (whose polymerization and / or crosslinking is carried out under the action of light, in particular ultraviolet light).

[0036] The part obtained by manufacturing a part using a three-dimensional printing machine according to the invention produces a part, commonly referred to as a "green" part, which is then subjected to a debinding step followed by a sintering step. Following these steps, the part is entirely composed of a metallic material in the case of using a metal powder, the binder having been removed. The debinding step consists of heating the part to a temperature above the boiling point of the binder used to manufacture the part. Debinding removes the binder. After debinding, sintering densifies the part by bridging the metallic particles together.

[0037] The invention also relates to a method of manufacturing a part using a three-dimensional printing machine according to the invention.

[0038] The invention also relates to a three-dimensional printing machine and a manufacturing process, characterized in combination by all or part of the characteristics mentioned above or below. List of figures

[0039] Other objects, features and advantages of the invention will become apparent from the following description, given by way of non-limiting example only, and which refers to the accompanying figures in which:

[0040] [Fig-1] represents a schematic side view of a machine according to the invention.

[0041] [Fig.2] represents a schematic front view of a machine according to the invention.

[0042] [Fig.3] represents a schematic side view of a machine according to the invention.

[0043] [Fig.4] represents a schematic top perspective view of a machine according to the invention.

[0044] [Fig.5] represents a schematic top view of a machine according to the invention.

[0045] Detailed description of an embodiment of the invention

[0046] Figures 1 to 5 illustrate a first embodiment of a three-dimensional printing machine according to the invention.

[0047] Identical, similar or analogous elements are designated by the same references in all figures.

[0048] The terms longitudinal, transverse, vertical, and their variants are used by way of non-limiting reference to the L, T, V trihedron as shown in Figure 4. The longitudinal direction (referenced as L in the figures) corresponds to the principal direction of movement of the print head and the powder material distribution device. The vertical direction (referenced as V in the figures) is the direction defined by gravity, and the transverse direction (referenced as T in the figures) is the direction perpendicular to the longitudinal and vertical directions.

[0049] The three-dimensional printing machine 1 shown in Figures 1 to 5 comprises:

[0050] - a chassis 2 comprising vertical uprights 3 and platforms 8, 9, 10 extending substantially horizontally between the vertical uprights 3,

[0051] - a first container, called powder reservoir 17, configured to be able to receive a powdered material chosen from the group consisting of metallic and ceramic powders, in particular metallic powders, serving as the basis for the manufacture of parts,

[0052] - a second tank, called construction tank 15, adapted to be able to receive a part manufactured by the printing machine,

[0053] - a printing enclosure 4 comprising a base 5, a plurality of side walls 6, 12, 13 and an upper wall 7, within which are arranged a movable printing head 86 and a device 80 for distributing the powdered material,

[0054] - means for moving the mobile printing head 86 within the enclosure 4 printing plates, arranged outside of it,

[0055] - means for moving the device 80 for distributing the powdered material within printing enclosure 4, arranged outside of it.

[0056] The movable print head 86 and the powder material distribution device 80 are movable along the longitudinal direction L. The movable print head 86 includes at least one print nozzle per jet configured to project a curable liquid composition, referred to as the binder, into the build tray 15. The print nozzles are movable in translation along the print head in the transverse direction T. The binder projected by the print head can, in particular, be selected from the group consisting of thermosetting polymers or resins and photopolymers.

[0057] To allow the means for moving the movable print head 86 and the powder material distribution device 80 to operate while located outside the print enclosure 4, the two main side walls 12, 13 of the print enclosure 4 each include a longitudinal through groove 40 equipped with two rows of brushes facing each other so as to allow translational movement of the carriages 31, 50 connected to the print head 86 and the carriages 30, 51 connected to the powder material distribution device 80. Instead of or in addition to said brushes, nothing prevents the provision of any other device for containing the powder material inside the print enclosure, such as flexible seals (made of elastomer, for example) or even flap bellows.Such a configuration limits the passage of metal powder through the components, thereby improving the operation and extending the lifespan of most of the mechanical and electronic components of the 3D printing machine by preventing any contact with fine particles, particularly fine metallic particles. Furthermore, since some metal powders can form explosive atmospheres (known as "ATEX"), a 3D printing machine according to the invention limits this risk of explosion and thus contributes to user safety.

[0058] The powder material distribution device 80 spreads a layer of powder material from the powder reservoir 17 into the build hopper 15 after each pass of the print head 86. After each layer of powder material has been prepared in the build hopper 15, the print head 86 sprays droplets of binder into the layer of powder material to form the desired part by successive layers stacked one on top of the other. After each pass of the print head 86, The infrared lamp 82 contributes to the hardening (or drying) of the binder, making the powdered material coated with binder cohesive, thus contributing to the hardening of each layer of the manufactured part. The powdered material distribution device 80, coupled to the infrared lamp 82, is in the form of an arm extending transversely within the printing chamber 4.

[0059] As can be seen in particular in figures 1 to 3, the means for moving the printing head 86 and the distribution device 80 each comprise two sliding carriages, that is to say a carriage 30 and a carriage 51 each connected to one end of the printing head 86, and a carriage 31 and a carriage 50 each connected to one end of the distribution device 80.

[0060] The means for moving the printing head 86 and the distribution device 80 also each comprise a motor 42, 45, eight pulleys 32, 33, 35, 36, 48, 49, 52, 53 driven by the motor 42, 45 and four bearing belts 37, 38, 55, 56, each bearing belt 37, 38, 55, 56 cooperating with a movable carriage 30, 31, 50, 51. [Fig. 3] is a schematic view of the side of the machine opposite to that shown in [Fig. 1]. Four pulleys 32, 33, 35, 36 and two bearing bands 37, 38 are thus arranged on one side (visible in [Fig.1]), and four other pulleys 48, 49, 52, 53 and two other bearing bands 55, 56 are arranged on the second side (visible in [Fig.3]).

[0061] The means for moving the mobile print head 86 include, a first carriage 30 configured to be able to be driven in translation along a first longitudinal direction of movement and a second carriage 51 configured to be able to be driven in translation along a second longitudinal direction of movement, parallel to the first longitudinal direction of movement.

[0062] Similarly, the means for moving the distribution device 80 include a third trolley 31 configured to be able to be driven in translation along the first longitudinal direction of movement and a fourth trolley 50 configured to be able to be driven in translation along the second longitudinal direction of movement, parallel to the first longitudinal direction of movement.

[0063] The motor 42 drives in rotation a first rotor 43 connected at each of its longitudinal ends to pulleys 33, 48 and the second motor 45 drives in rotation a second rotor 46 connected at each of its longitudinal ends to pulleys 36, 52. Each rotor 43, 46 is also provided with a bearing 44, 47 at its end opposite to that connected to the motor 42, 45.

[0064] Each mobile carriage 30, 31, 50, 51 is mounted on a guide rail 34, 58, a rail being arranged on either side of the main side walls 12, 13 of the printing enclosure 4.

[0065] Each carriage serves as a translational guide device, and other types of translational guide devices can replace the carriages. Similarly, each transmission device can be selected from the group consisting of mechanical cable and / or belt drives, or mechanical rack and pinion drives and ball screws.

[0066] All the movable carriages 30, 31, 50, 51 and the rails 34, 58 are therefore arranged outside the printing chamber 4, that is to say beyond the side walls 12, 13 separating the area in which metal powder may be found from the outside of it. Similarly, the motors 42, 45, the pulleys 32, 33, 35, 36, 48, 49, 52, 53 and the running belts 37, 38, 55, 56 are also arranged outside the printing chamber 4, that is to say beyond the side walls 6 of the printing chamber 4.

[0067] The printing chamber 4 forms a generally parallelepiped-shaped space extending between two longitudinal ends of the printing machine. The two main lateral walls 12, 13 of the printing chamber 4 are each provided with at least one longitudinal through groove equipped with brushes configured to allow the translational movement of the carriages 31, 50 connected to the printing head 86 and to allow the translational movement of the carriages 30, 51 connected to the distribution device 80. This configuration allows the main mechanical components of the three-dimensional printing machine to be extracted from the printing chamber 4, within which fine particles formed from the powder constitute the powdered material necessary for manufacturing the part.

[0068] The powder reservoir 17 and the build tray 15 are each removable and can therefore be extracted from the printing machine for maintenance and to be emptied or filled with powdered material in the case of the powder reservoir, and before / after the machine has manufactured a part. This facilitates the use of the printing machine. As can be seen in Figures 1, 3, and 4, the printing machine includes conveyor wheels 22 for the powder reservoir 17 arranged opposite it, and conveyor wheels 22 for the build tray 15 arranged opposite it. These conveyor wheels improve the ergonomics of the printing machine.

[0069] A three-dimensional printing machine as shown in Figures 1 to 5 includes a lifting platform 20 for the powder reservoir 17 and the build tray 15. The lifting platform 20 is mounted on feet 21 and cylinders 23 for moving the powder reservoir 17 and the build tray 15 between a lower position, in which the powder reservoir 17 and the build tray 15 are substantially at the level of the conveyor wheels, in order to allow their removal from the machine, and an upper position in which the powder reservoir 17 and The build hopper 15 opens into the printing chamber 4. In addition, the powder reservoir 17 includes a lifting platform operated by a cylinder (not visible in the figures) allowing the printing chamber 4 to be supplied with powdered material as it is consumed, depending on the fill level of the reservoir 17. Similarly, the build hopper 15 is also equipped with a lifting platform operated by a cylinder (not visible in the figures) allowing the position of the build hopper 15 to be progressively adjusted during the manufacturing of a three-dimensional part in a substantially vertical direction (orthogonal to the longitudinal directions of movement of the carriages).

[0070] The printing machine can also be equipped with various sensors (such as temperature sensors, a hygrometer, etc.). A pyrometer, for example, can be used to measure the temperature of each layer of powder formed. The temperature inside the printing chamber 4 is also monitored and regulated, for example, based on the temperature measured by the pyrometer.

[0071] The three-dimensional printing machine also includes a block 25 housing some of the machine's electronics and resting on the intermediate platform 9 of the chassis 2. The print head 86 is connected to this block 25 by an articulated cable chain 62 so as to be able to follow the movements of the print head. A second articulated cable chain 60 connects electrotechnical elements (other than the print head 86) located in the printing enclosure 4 to the electronic block 25. These elements may include the pyrometer, but also a motor and a Y-axis limit switch, which has not been mentioned until now, since the print head is also movable on the Y-axis, which is parallel to the print arm.

[0072] In addition, as can be seen in [Fig.3], a third articulated cable chain 61 connects the powder material distribution device 80 and its electrotechnical components (including a roller rotation motor and the infrared lamp 82) to the electronic block 25.

[0073] As can be seen in Figures 1 and 3, a three-dimensional printing machine also includes a binder reservoir 93 connected by fluid communication to the print head 86. It also includes a container 92 for holding a cleaning fluid for the print head 86 and a container 94 for collecting the binder and / or cleaning fluid that has circulated inside the print head 86 in order to purge and / or clean it. These elements are arranged on the lower platform 10 of the three-dimensional printing machine 1.

[0074] As can be seen in Figures 1, 4 and 5, the bottom 5 of the printing chamber 4 has two slots 63, 64 arranged near the build tray 15 allowing to allow any excess powdery material displaced by the distribution device 80 to pass to a powder discharge outlet 27 connected to a container 28 for recycling, particularly within the printing machine itself.

[0075] The printing chamber 4 further includes a suction opening 70 through the side wall 6 which can be connected to a suction source. This further limits any leakage of the powdered material from the printing chamber 4, in particular via the grooves 40.

[0076] The printing machine can also be equipped with 98 movement wheels equipped with a brake allowing the machine to be moved more easily on the ground and to be stabilized in a fixed position during the manufacture of a part.

[0077] The upper wall 7 of the printing enclosure 4 may be formed entirely from a door or include a door (not shown). It may be a hinged door. It may be made of a transparent material such as glass, allowing visual monitoring of the progress of the three-dimensional printing without having to open the printing enclosure 4.

[0078] A three-dimensional printing machine such as shown in Figures 1 to 5 has, for example, a height of approximately 1.20 m, a length of approximately 1.20 m and a width of approximately 0.80 m.

[0079] The dimensions of a three-dimensional printing machine according to the invention, and in particular those of the build vat, can of course be modified and adapted according to the size of the parts or objects that one wishes to manufacture in particular.

Claims

Demands

1. Three-dimensional printing machine (1) comprising: - a first hopper, called powder reservoir (17), configured to receive a powdered material, - a second hopper, called build hopper (15), adapted to receive a part manufactured by said printing machine, - a movable printing head (86) configured to project a hardenable liquid composition, called binder, towards said build hopper (15), - a distribution device (80) for said powdered material configured to form, from said powder reservoir (17), at least one layer of said powdered material within said build hopper (15), characterized in that it further comprises: - a printing chamber (4) comprising a bottom (5) and a plurality of walls (6, 12, 13),said printing chamber (4) being configured to receive said movable printing head (86) and said device (80) for distributing said powdered material, said construction tray (15) opening into said printing chamber (4), - means for moving said movable printing head (86) within said printing chamber (4), - means for moving said device (80) for distributing said powdered material within said printing chamber (4), said means for moving said printing head (86) and said distribution device (80) being disposed outside said printing chamber (4).

2. Machine according to claim 1, characterized in that said means for moving said printing head (86) comprise at least one translational guidance device along at least one longitudinal direction of movement, and said means for moving said dispensing device (80) comprise at least one translational guidance device along said longitudinal direction of movement.

3. Machine according to claim 2, characterized in that said means for moving said printing head (86) and said means of moving said distribution device (80) further include each at least one transmission device coupled to a motor (42, 45) so as to be able to drive said at least one guiding device in translation.

4. Machine according to claim 3, characterized in that said means for moving said movable print head (86) comprise two translational guidance devices, a first translational guidance device being configured to be able to be driven in translation along a first longitudinal direction of movement and a second translational guidance device being configured to be able to be driven in translation along a second longitudinal direction of movement, said first longitudinal direction of movement and said second longitudinal direction of movement being parallel to each other.

5. Machine according to any one of claims 3 or 4, characterized in that said means for moving said distribution device (80) comprise two translational guidance devices, a third translational guidance device being configured to be able to be driven in translation along a first longitudinal direction of movement and a fourth translational guidance device being configured to be able to be driven in translation along a second longitudinal direction of movement, said first longitudinal direction of movement and said second longitudinal direction of movement being parallel to each other.

6. Machine according to any one of claims 2 to 5, characterized in that each translational guidance device is a movable carriage (30, 31, 50, 51) mounted on a rail (34, 58).

7. Machine according to any one of claims 3 to 6, characterized in that said means for moving said printing head (86) and said distribution device (80) comprise a first motor (42) driving in rotation a first rotor (43) connected at each of its longitudinal ends to a pulley (33, 48) and a second motor (45) driving in rotation a second rotor (46) connected at each of its longitudinal ends to a pulley (36, 52).

8. Machine according to any one of claims 2 to 7, characterized in that the walls of said printing enclosure (4) comprise two main side walls (12, 13), each provided with at least one longitudinal through groove (40) configured to permit the translational movements of said translational guidance device of said printing head (86) and of said translational guidance device of said distribution device (80).

9. Machine according to any one of claims 1 to 8, characterized in that said powder tank (17) and said construction tray (15) are removable and in that said printing machine includes conveying wheels (22) for said powder tank (17) and said construction tray (15).

10. Machine according to claim 9, characterized in that it comprises a lifting platform (20) for said powder tank (17) and said build tray (15), configured to be able to move said powder tank (17) and said build tray (15) between at least one lower position, in which said powder tank (17) and said build tray (15) are substantially at the level of said conveyor wheels, and at least one upper position in which said powder tank (17) and said build tray (15) open into said printing chamber (4).

11. Machine according to any one of claims 1 to 10, characterized in that it comprises a reservoir (93) of said binder.

12. Machine according to any one of claims 1 to 11, characterized in that said powdered material is chosen from the group formed of metallic powders.

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