BINDER JET PRINTER AND METHOD THEREFOR

Abstract

A binder jet printer for additive manufacturing includes a build chamber and at least one further build chamber, a powder supply source configured to provide powder to both of the build chambers, a leveling assembly for leveling the powder beds in the build chambers to form leveled powder beds in the build chambers, a print head configured for depositing binder on the leveled powder beds, a radiant configured to irradiate the powder beds, and a control unit. The control unit is configured to control the powder supply source to provide powder to the build chamber and the further build chamber, control the leveling assemblies in both build chambers, control the print head to deposit binder on the leveled powder beds, wait a predetermined time for the deposited binder to soak into the powder beds, and control the radiant to irradiate the soaked powder beds in the build chambers.

Claims

1. A binder jet printer for additive manufacturing, comprising: a build chamber; a powder supply source configured to provide powder to the build chamber; a leveling assembly arranged for leveling a powder bed in the build chamber, thereby forming a leveled powder bed in the build chamber in which a green body is formed; a print head configured for depositing binder on the leveled powder bed in the build chamber; a radiant configured to irradiate the leveled powder bed in the build chamber; a control unit configured to: control the powder supply source to provide powder to the build chamber; control the leveling assembly to level the powder bed in the build chamber; control the print head to deposit binder on the leveled powder bed in the build chamber; wait a predetermined time for the deposited binder to soak the leveled powder bed in the build chamber; and control the radiant to irradiate the soaked powder bed in the build chamber; and at least one further build chamber the control unit being further configured to: control the powder supply source to provide powder to the at least one further build chamber; control the leveling assembly to level the powder bed in the at least one further build chamber; control the print head to deposit binder on the leveled powder bed in the at least one further build chamber; wait a predetermined time for the deposited binder to soak the leveled powder bed in the at least one further build chamber; control the radiant to irradiate the soaked powder bed in the further build chamber; and control at least two of the powder source, leveling assembly, print head, and the radiant to simultaneously serve the build chamber and the at least one further build chamber.

2. The binder jet printer for additive manufacturing according to claim 1, wherein the leveling assembly includes a first roller.

3. The binder jet printer for additive manufacturing according to claim 2, wherein the leveling assembly includes a second roller.

4. The binder jet printer for additive manufacturing according to claim 3, wherein the first roller is associated with the build chamber, and the second roller is associated with the at least one further build chamber, the control unit being further configured to level the powder bed of the build chamber with the first roller, and to level the powder bed of the at least one further build chamber with the second roller.

5. The binder jet printer for additive manufacturing according to claim 3, wherein the first roller and the second roller are configured to move freely in a working direction independent of each other.

6. The binder jet printer for additive manufacturing according to claim 4, wherein the first roller and the second roller shares a common linear guide.

7. The binder jet printer for additive manufacturing according to claim 1, wherein the build chamber and the at least one further build chamber are arranged along a working direction of the binder jet printer in a non-overlapping relation with each other.

8. The binder jet printer for additive manufacturing according to claim 6, wherein the build chamber and the at least one further build chamber are in line with each other.

9. A method of a binder jet printer for additive manufacturing, wherein the binder jet printer comprises: a build chamber; a powder supply source configured to provide powder to the build chamber; a leveling assembly for leveling a powder bed in the build chamber, thereby forming a leveled powder bed in the build chamber; a print head configured for depositing binder on the leveled powder bed in the build chamber; a radiant configured to irradiate the leveled powder bed in the build chamber; and wherein the method comprises the steps of: a) controlling the powder supply source to provide powder to the build chamber; b) controlling the leveling assembly to level the powder bed in the build chamber, thereby forming a leveled powder bed in the build chamber; c) controlling the print head to deposit binder on the leveled powder bed in the build chamber; d) waiting a predetermined time for a deposited binder to soak the leveled powder bed in the build chamber; e) controlling the radiant to irradiate the soaked powder bed in the build chamber; and wherein the binder jet printer further comprises at least one further build chamber, and the method further comprises performing at least two of the above steps a) to e) simultaneously on the build chamber and on the at least one further build chamber, or the method further comprises performing any of steps a), b), d) or e) simultaneously on the build chamber and on the at least one further build chamber.

10. The method of a binder jet printer according to claim 8, wherein the leveling assembly includes a first roller for leveling the power bed, and the step b) of leveling further comprises leveling powder in a build chamber by means of the first roller.

11. The method of a binder jet printer according to claim 10, wherein the leveling assembly further includes a second roller, wherein the first roller is associated with the build chamber, and the second roller is associated with the at least one further build chamber, and the step b) of leveling further comprises: leveling the build chamber with the first roller; and/or leveling the at least one further build chamber with the second roller.

12. A non-transitory computer readable media having information embodied therein, the information including instructions for a machine to execute the method according to claim 7.

Description

LIST OF DRAWINGS

[0029] The invention will in the following be more closely described by means of embodiment examples, with reference to appended drawings. In the drawings:

[0030] FIG. 1 is a schematic view of a binder jet printer according to an embodiment of the present invention,

[0031] FIG. 2 is a schematic view of the binder jet printer according to an embodiment of the present invention,

[0032] FIG. 3 is a flowchart illustrating a method according to an embodiment of the present invention,

[0033] FIG. 4 is a schematic top view of the binder jet printer according to an embodiment of the present invention, and

[0034] FIG. 5 is a schematic view of a non-transitory computer readable media and the machine.

DETAILED DESCRIPTION OF EMBODIMENTS

[0035] A binder jet printer 100 according to an embodiment of the present invention is very schematically illustrated in FIG. 1. The binder jet printer, generally designated 100, comprises a build chamber 101 of arbitrary cross section, and at least one further build chamber 102, 103 of arbitrary cross section, preferably the same as the cross section of the build chamber 101. Each build chamber is provided a bottom which is displaceable in a vertical direction, such that the printed object, e.g the green body, grows downwardly in the build chamber.

[0036] In order to provide powder to the build chamber the binder jet printer comprises a powder supply source 106. This powder supply source 106 may be of push-feed type in which the powder supply source is arranged close and in plane with the build chamber and a piston push powder upwards after which it is pushed over to the build chamber. The powder supply source may also be of hopper-type, in which a reservoir with powder is suspended above a build chamber, wherein the reservoir is provided a valve which controls the supply of powder to the build chamber.

[0037] The binder jet printer further comprises a leveling assembly 104. The leveling assembly is provided for leveling the powder supplied to the build chamber by the powder supply source. It is of great importance that the leveling is precisely performed in a repetitive manner, such that a powder layer of uniform thickness is formed each time the leveling assembly levels the powder bed.

[0038] The binder jet printer further comprises a print head 107 configured for depositing binder on a leveled powder bed in a build chamber. The print head 107 is configured to supply droplets of binder to the leveled powder bed for forming said green body in the build chamber.

[0039] The soaking refers to the time it takes for the binder to penetrate the top powder layer of the leveled powder bed down to the previous layer so that the two layers are bound together, which ranges from a fraction of a second to several minutes.

[0040] The binder jet printer also comprises a radiant 105 which is configured to irradiate a powder bed in a build chamber. This irradiation may be provided to evaporate at least some of the fluid (e.g. solvent) in the binder to avoid it bleeding through the next powder layer to be leveled from below. This could potentially cause binder and thus powder to stick to the roller. This irradiation may also enhance the solidification of the binder in the powder bed. The radiant 105 may be a heating element, a light source, or a microwave source for example. The type of radiant is selected dependent on the type of binder used. It may be important that the binder is somewhat adhesive after irradiation by the radiant in order to enhance the binding to the subsequent layer.

[0041] The binder jet printer also comprises a control unit 108 for control of at least the above parts 104, 105, 106, 107 of the printer. The control unit 108 may be a computer comprising a processor and a memory. But the control unit may also be a programmable gate array. In any case, the control unit 108 is configured to: [0042] control the powder supply source to provide powder to a build chamber. [0043] control the leveling assembly to level the powder bed in the build chamber. [0044] control the printer to deposit binder on the leveled powder bed in the build chamber. [0045] wait a predetermined time for the deposited binder to soak the powder bed in the build chamber. [0046] control the radiant to irradiate the soaked powder bed in the build chamber. [0047] control the powder supply source to provide powder to the at least one further build chamber. [0048] control the leveling assembly to level the powder bed in the at least one further build chamber. [0049] control the printer to deposit binder on the leveled powder bed in the at least one further build chamber. [0050] wait a predetermined time for the deposited binder to soak the powder bed in the at least one further build chamber. [0051] control at least two of the powder source, leveling assembly, printhead, and the radiant to simultaneously serve the build chamber and at least one further build chamber.

[0052] By having a binder jet printer with the above features it is possible to simultaneously deposit binder in one build chamber while a further build chamber is leveled, soaked, irradiated, or supplied with powder. This will allow a printhead to operate more continuously without longer stops associated with waiting for soaking and leveling for example. A further advantage is that objects of different sizes may be printed in different build chambers. This makes it possible to remove and exchange the build chamber which is ready, while the build chamber with the other objects still prints. Having a build chamber with printed objects of the same sizes makes it easier to obtain optimum curing.

[0053] Now with reference made to FIG. 2 another embodiment of a binder jet printer will be disclosed. This embodiment differs from the embodiment disclosed with reference made to FIG. 1 in that the leveling assembly 104 includes a first roller 201, the first roller is associated with the build chamber 101. The leveling assembly 104 further comprises a second roller 402 associated with the at least one further build chamber 102,103. This association should be interpreted as a logical association in that a specific roller is always used to level a specific build chamber. This means that if the first roller is associated with the build chamber, then the first roller is always used to level the build chamber. The second roller 202 is associated with the at least one further build chamber. Thus, the second roller 202 is used for leveling the at least one further build chamber 102,103.

[0054] A method of a binder jet printer is schematically illustrated in FIG. 3 as a flow diagram. The method is suitable for a binder jet printer according to the embodiments described hereinabove comprising a build chamber 101 and at least one further build chamber 102,103. The method comprises the steps of: [0055] a) (301): controlling the powder supply source to provide powder to a build chamber, thereby forming a powder bed in the build chamber [0056] b) (302): controlling the leveling assembly to level the powder bed in a build chamber [0057] c) (303): controlling the print head to deposit binder on a leveled powder bed in a build chamber [0058] d) (304): waiting a predetermined time for a deposited binder to soak in a powder bed in a build chamber [0059] e) (305): controlling the radiant to irradiate a soaked powder bed in a build chamber.

[0060] The method further comprises performing at least two of the above steps a) to e) simultaneously on the build chamber and on the at least one further build chamber, or the method further comprises performing any of steps a), b), d) or e) simultaneously on the build chamber and on the at least one further build chamber.

[0061] Thus the build chamber and the at least one further build chamber may be processed in parallel and the printhead will operate more continuous compared to a binder jet printer with only one build chamber.

[0062] FIG. 4 shows a schematic top view of a binder jet printer (400) according to the embodiment disclosed with reference made to FIG. 2. The binder jet printer 400 comprises a build table 404 with a build chamber 101, a further build chamber 102, and yet a further build chamber 103. These build chambers are arranged in line with each other along a working direction 405. A pair of guide rails 403 are arranged in the working direction on the sides of the build chambers. The binder jet printer comprises a first roller 201 that is provided with linear bearings configured to glide on the linear guides, this first roller is associated with the build chamber 101. The binder jet printer further comprises a second roller 202 also provided with linear bearings configured to glide on the pair of linear guides 403. The second roller is associated with the further build chamber 102 and the yet further build chamber 103.

[0063] The printhead 107 is also configured to move along the guide rails, and in some embodiments it may also be configured to move in a direction perpendicular to the guide rails. The printhead 107 may also in some embodiments be configured to move in a direction normal to the build frame, generally designated the X or Y direction.

[0064] The binder jet printer 100 further comprises a powder supply source 106 in this embodiment, a hopper-type powder supply source. Not shown in this FIG. 4 the radiant 105 is arranged to selectable irradiate one of the build chambers. This irradiation may for example be heat radiation.

[0065] The control unit 108 (not shown in FIG. 4) is connected to the first roller 201 and to the second roller 202. Furthermore, the control unit 108 is connected to the printhead 107 and to the powder supply source 106. Since the first roller 201, the second roller 202 the printhead 107 and the powder supply source 106 share the same linear guides 403, the order of the devices arranged on the linear guides is fixed. This means for example that the printhead 107 cannot jump over the first roller 201, or the powder supply source 106.

[0066] The binder jet printer will now be described using a scenario.

[0067] In the scenario, the build chamber 101 is leveled with the first roller 201, the printhead 107 moves to the build chamber 101 and begins to deposit binder on the leveled layer, simultaneously the powder supply source 106 provides the yet further build chamber 103 with powder, this is immediately followed by leveling with the second roller 202. When the printhead is ready with printing in the build chamber 101, the print head moves away to the left in FIG. 4, in order to allow the deposited binder to soak. For example may the printhead start to deposit binder in the further build chamber 102.

[0068] In one embodiment, the powder supply source is free to jump over the printhead, this can be achieved with a second pair of linear guides provided to the powder supply source. This may provide a better utilization of the printhead 107.

[0069] FIG. 5 shows schematically a machine 501 comprising a non-transitory computer readable media 502, in which instructions are stored such that methods disclosed above with reference made to the embodiments are executed by the machine.

[0070] Many modifications and variations of the binder jet printer are possible, for example may the printhead 107 change place with the powder supply source 106. In an alternative embodiment the leveling assembly may comprise a scraper instead of the roller, or in combination with the roller.