Printing device for 3D printing

Abstract

The present invention relates to a printing device (10) for a 3D printer. The printing device comprises a metering unit (18) for melting and plasticizing a material (38) to be printed and an output unit (14) for printing the material (38) provided by the metering unit (18). The metering unit (18) and the output unit (14) are arranged separately from each other but can be connected to each other, wherein the output unit (14) can be transported to the metering unit (18) to receive the material (38), and in order to connect the output unit (14) to the metering unit (18), a nozzle (74) of the output unit (14) and a coupling portion (62) of the metering unit (18) are in contact with each other.

Description

Technical Field

[0001] The invention relates to a printing device for a 3D printer and a method for operating such a printing device. Background Art

[0002] 3D printers for variable-viscosity materials use a solid phase of the material as a starting material, generate a liquid phase from it, and selectively apply this liquid phase to areas of the object being manufactured. These 3D printers include a print head in which the starting material for printing is prepared. The material is then conveyed through channels in the print head.

[0003] Furthermore, means are provided for generating a relative movement between the print head and the work surface on which the object is to be formed. Either only the print head, only the work surface, or both the print head and the work surface can be moved. To influence the application of material to the work surface, an actuator is typically provided in the print head, which exerts a force on the metering region.

[0004] WO 2018 / 086792 A1 discloses a print head for a 3D printer. The print head includes a supply through which a material to be printed is supplied to the print head. This material is melted and plasticized in the print head. The melted material is conveyed within the print head to an outlet through which it is applied to the printing area. Summary of the Invention

[0005] Within the scope of the present invention, a printing device for a 3D printer has been developed. The printing device comprises a metering unit for melting and plasticizing a material to be printed and an output unit for printing the material provided by the metering unit.

[0006] In the context of the present invention, a metering unit is understood to be, in particular, an area where raw material is supplied, wherein the raw material is melted and plasticized in the metering unit. Furthermore, molten material can also be provided in metered quantities. In this context, a dispensing unit is an area where material can be released for producing a 3D body.

[0007] According to the invention, the metering unit and the output unit are arranged separately from each other but can be connected to each other, wherein the output unit can be transported to the metering unit to receive the material, and in order to connect the output unit to the metering unit, the nozzle of the output unit and the coupling part of the metering unit are in contact with each other.

[0008] Therefore, in the present invention, the metering unit and the output unit are separated from each other. However, the two units can be connected to each other for receiving material. Therefore, the output unit has a volume capable of receiving a certain amount of molten material.

[0009] It has been found that compared to a print head in which the metering unit and the dispensing unit are arranged together, this offers the following advantages: in particular, by separating the two units, a smaller weight is moved, which essentially comprises the dispensing unit with the molten material. This improves the dynamics of such a 3D printer.

[0010] By separating the different functions, the corresponding units can be designed to be more optimally functional. For example, an actuator that exerts a force on the material in the dosing unit no longer influences the output quantity in the output unit. This allows the actuator to be designed more cost-effectively and efficiently, for example, in terms of the desired result.

[0011] Separating the metering unit from the delivery unit has the added advantage of improving material utilization. In a printhead with both a metering unit and a delivery unit, the introduced material must be consumed to prevent the melted material from later solidifying in the delivery unit. Consequently, in many cases, not all of the material is used, resulting in waste. In contrast, only the required amount can be filled from the metering unit into the delivery unit, thereby maximizing material utilization and reducing costs. This allows for more economical manufacturing using this printing device.

[0012] To further improve economic efficiency, a preferred embodiment of the present invention provides multiple discharge units that alternately interact with a single metering unit to receive material. This means that only one metering unit is required for multiple discharge units. Consequently, a separate metering unit is not required for each discharge unit. This increases the capacity utilization of the metering units and thus the economic efficiency of the system.

[0013] In another preferred embodiment of the present invention, for example in an industrial plant, the output unit is assigned to different pressure chamber units that are separated from each other. Thus, the output units of multiple printing processes that produce different workpieces can work with only one metering unit.

[0014] A separate transport system is preferably provided for transporting the output unit to the dosing unit. The transport system is the system that brings the output unit from the area where the workpieces are printed to the dosing unit. This can be achieved, for example, by a rail system along which the output unit is transported. In one embodiment, the print axis can be extended so that it reaches the dosing unit. This is particularly advantageous in smaller systems.

[0015] In another embodiment, the output unit can also be brought to the metering unit by a robot. In the same way, the output unit can be transported back from the metering unit to the workpiece. This transport system is particularly advantageous in larger systems.

[0016] The advantage of this transport system is that the export unit can be kept simple and, in particular, specialized in its export function. This reduces the cost of the export unit. Preferably, the transport system transports multiple export units, thereby improving the transport system's capacity utilization. Consequently, the cost of such a transport system can be correspondingly reduced.

[0017] In one advantageous embodiment, the transport system includes a heatable transport carrier in which the dispensing unit is received. The transport carrier is part of the transport system and directly holds the dispensing unit. The dispensing unit is at least partially surrounded on the outside by heatable parts of the transport carrier. Heating the transport carrier minimizes cooling of the molten material in the dispensing unit during transport, thereby extending the storage time of the material in the dispensing unit.

[0018] The output unit is advantageously arranged in a replaceable manner in the printing device. In other words, the output unit currently in use can be replaced with another one. This has the advantage that output units with different nozzle openings, cross-sections, or volumes can be used for printing. The color of the output unit can also be changed. This allows the output unit to be more optimally adapted to the required production of the workpiece, thereby improving workpiece production. The output unit can advantageously be replaced during operation. This eliminates the need to interrupt production, enabling faster and more economical production. The output unit is preferably replaced automatically, thereby reducing personnel costs.

[0019] The dispensing unit preferably has an dispensing piston that interacts with a device that, when receiving material, can exert a force opposite to the dispensing unit's filling direction. Thus, while the dispensing unit is being filled at the metering unit, a force is exerted against the material to be received. The dispensing piston is a piston that can move within the dispensing unit and act on the material received therein. In a preferred embodiment, this device is a spring. This force has the advantage that it brakes the return movement of the dispensing piston, thereby ensuring air-free filling of the dispensing unit.

[0020] In one advantageous embodiment, a discharge piston driven by a servo motor is provided to discharge the material for printing. The servo motor has the advantage that it increases the accuracy and repeatability of the material discharge from the discharge unit. This significantly improves the quality of the workpiece.

[0021] Different from the known print heads in the prior art, the servomotor of the output unit acts only on the homogeneous melt. Thus, a low power is required for this servomotor, making it possible to realize this servomotor at a reduced cost.

[0022] To ensure a high force in the metering unit, the metering unit preferably has a metering piston for conveying the material from the metering unit, which is driven by a hydraulic device or an electric motor. Here, the metering piston is also movably arranged in the metering unit and exerts a force on the material in the metering unit to convey it from the metering unit to the output unit. This allows sufficient force to be provided in the metering unit, compared to output units that require high precision. By separating the output unit from the metering unit, each unit can be optimized in terms of functionality.

[0023] The present invention also describes a method for operating such a printing device. The method comprises the following steps: transporting a dispensing unit to a metering unit, connecting the dispensing unit to the metering unit, filling the dispensing unit with the material to be printed, and transporting the dispensing unit to the area to be printed. When connecting the metering unit to the dispensing unit, the two units are tightly connected to each other so that material can be transferred from the metering unit to the dispensing unit. This method achieves the advantages described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] An exemplary embodiment of the invention is shown in the drawings and explained in more detail in the following description. The drawings show:

[0025] Figure 1 an embodiment of a printing device during filling of an output unit,

[0026] Figure 2 an embodiment of the printing device during transport of the output unit,

[0027] Figure 3 An embodiment of a printing device having a plurality of output units, which are arranged in different pressure chamber units, and

[0028] Figure 4 A method for operating a printing device. DETAILED DESCRIPTION

[0029] Figure 1 An exemplary embodiment of the printing device 10 is shown when filling the output unit 14 . Figure 1 This is shown in a cross-sectional view. In addition to the dispensing unit 14, the printing device 10 also includes a metering unit 18. The metering unit 18 comprises a base body 22 on which an inlet funnel 26 is arranged. A solid starting material 30 can be introduced into the inlet funnel 26. The inlet funnel 26 is directly connected to a metering chamber 34 formed by the base body 22. In this metering chamber 34, the starting material 30 is melted and plasticized to form a printable material 38.

[0030] The metering chamber 34 has a lateral metering piston opening 42. A metering piston 46 is arranged in this metering piston opening 42 and projects into the metering chamber 34. The metering piston force F D The material 38 in the metering chamber 34 can be acted upon by the metering piston 46 so that it can be pressed in the direction of the metering feed opening 50 lying opposite the metering piston opening 42 .

[0031] At the metering delivery opening 50, the metering unit 18 has a coupling element 54 forming a channel 58, so that the material 38 discharged through the metering delivery opening 50 can be fed to a coupling point 62 of the coupling element 54. The discharge unit 14 is arranged at the coupling point 62 so that it can receive the molten material 38.

[0032] The output unit 14 has an output body 66 that forms an output chamber 70 in which the molten material 38 can be received. A nozzle 74 is formed at the end of the output body 66 that is connected to the coupling portion 62, through which the molten material 38 can be received. Similarly, the material 38 is applied to a workpiece (not shown) through the nozzle 74.

[0033] Arranged in the outlet chamber 70 is an outlet piston 78, through which the material 38 can be discharged. Arranged above the outlet piston 78 is a device 82, by which a force F is exerted in the opposite direction of the filling during filling. F In this embodiment, the device 82 is implemented as a schematically indicated spring. By applying a force F to the output piston 78 F Ensure that the output unit 14 is filled without air. During filling, the output piston 78 moves in the direction of the spring 82.

[0034] Figure 2 An exemplary embodiment of a printing device 10 is shown during the transport of a dispensing unit 14. In particular, the figure shows a transport system 86 of the printing device 10. In this exemplary embodiment, the transport system 86 comprises an axis unit 90, which is schematically shown here connected to a motor M. The dispensing unit 14 can be transported between the metering unit 18 and a workpiece to be produced (not shown) via this transport system 86. The transport can be performed automatically.

[0035] In this embodiment, the transport system 86 also includes a transport carrier 94 that surrounds the dispensing unit 14 on the outside. The transport carrier 94 in particular includes a heater 98, which allows the material in the dispensing unit 14 to be heated during transport. This allows the material to remain in the dispensing unit 14 for a longer period of time, allowing for longer transport routes or times. In an embodiment not shown here, the transport system 86 can also be implemented by a robot.

[0036] Figure 3 An exemplary embodiment of a printing device 10 is shown having multiple output units 14, which are arranged in different pressure chamber units 102. Each pressure chamber unit 102 produces a different workpiece. An output unit 14 is arranged in each pressure chamber unit 102 and is received by a print head body 106 on which the output unit 14 can be moved. Like the transport carrier 94, the print head body 106 can also be equipped with a heater (not shown).

[0037] The pressure chamber unit 102 is connected to the metering unit 18 in particular via a single transport system 86. Thus, a plurality of output units 14 can be connected to a single metering unit 18 via a single transport system 86. This improves the capacity utilization of the assembly.

[0038] exist Figure 4 , a method for operating the printing device 10 is shown in FIG. In a first step A, the output unit 14 is transported to the metering unit 18. In a second step B, the output unit 14 is coupled to the metering unit 18. A sealed connection is thereby formed between the metering unit 18 and the output unit 14. In a subsequent step C, the output unit 14 is filled from the metering unit 18. This may involve completely filling the output unit 14. Alternatively, the output unit 14 may be filled with only a specific amount of material. This amount is measured to ensure full utilization of the material. In a final step D, the output unit 14, thus filled, is transported to the printing area. This method may be repeated multiple times during printing.

Claims

1. A printing device (10) for a 3D printer, comprising: a metering unit (18) for melting and plasticizing the material (38) to be printed and a dispensing unit (14) for printing the material (38) provided by the metering unit (18), The metering unit (18) and the output unit (14) are arranged separately from each other but can be connected to each other, the output unit (14) can be transported to the metering unit (18) for receiving material (38), and the nozzle (74) of the output unit (14) and the coupling part (62) of the metering unit (18) are in contact with each other for connecting the output unit (14) to the metering unit (18), and the output unit (14) has an output piston (78) which interacts with a device (82) by means of which a force (F) can be exerted in the opposite direction to the filling direction of the output unit (14) when receiving material (38). F ).

2. The printing device (10) according to claim 1, characterized in that A plurality of dispensing units (14) are provided, which interact alternately with individual metering units (18) for receiving material (38).

3. The printing device (10) according to claim 2, characterized in that The output units (14) are assigned to different pressure chamber units (102) that are separate from one another.

4. The printing device (10) according to any one of claims 1 to 3, characterized in that A separate transport system (86) is provided for transporting the output unit (14) to the dosing unit (18).

5. The printing device (10) according to claim 4, characterized in that The transport system (86) has a heatable transport carrier (94) in which the output unit (14) is received.

6. The printing device (10) according to any one of claims 1 to 3 and 5, characterized in that The output unit (14) is arranged in the printing device (10) in a replaceable manner.

7. The printing device (10) according to any one of claims 1 to 3 and 5, characterized in that The output unit (14) has an output piston (78) which is driven by a servo motor so as to be able to deliver material (38) for printing.

8. The printing device (10) according to any one of claims 1 to 3 and 5, characterized in that The metering unit (18) has a metering piston (46) for conveying the material (38) in the metering unit (18), and the metering piston is driven by a hydraulic mechanism or an electric motor.

9. A method for operating a printing device (10) according to any one of the preceding claims, wherein: The method comprises the following steps: - transporting the output unit (14) to the metering unit (18), - connecting the output unit (14) to the metering unit (18), - filling the output unit (14) with the material (38) to be printed, and - transporting the output unit (14) to the area to be printed.

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