Printing device for a 3D printer

Abstract

A printing device (10) for a 3D printer, comprising a metering device (18) for melting and plasticizing a material (38) to be printed, and a discharging device (14) for printing the material (38) provided via the metering device (18), wherein the metering device (18) and the discharging device (14) are separate from one another and connectable to one another, wherein the discharging device (14) is transportable to the metering device (18) to receive material (38) and, to connect the discharging device (14) to the metering device (18), a coupling point (61) of the discharging device (14) and a coupling point (62) of the metering device (18) come into contact with one another, wherein the metering device (18) has, at a metering delivery opening (50), a coupling element (54) which forms a channel (58), the material (38) dispensed via the metering delivery opening (50) being deliverable to the coupling point (62) of the coupling element (54), and wherein the coupling element (54) has, in the region of the coupling point (62), a closing device (91) for opening and closing the channel (58). The disclosure also relates to a method for operating the printing device (10).

Description

[0001] Description

[0002] Title:

[0003] Printing device for a 3D printer

[0004] The present invention relates to a printing device for a 3D printer and a method for operating such a printing device.

[0005] State of the art

[0006] A 3D printer for a material with variable viscosity receives a solid phase of this material as a starting material, creates a liquid phase from it, and selectively deposits this liquid phase at the locations that belong to the object to be created. Such a 3D printer includes a print head in which the starting material is prepared for printing. The material is then transported through channels within the print head.

[0007] Furthermore, means are provided for generating relative movement between the print head and the work surface on which the object is to be created. This can involve moving either the print head alone, the work surface alone, or both the print head and the work surface. To influence the dispensing of the material onto the work surface, an actuator is usually provided in the print head, which applies a force to a dispensing zone.

[0008] A print head for a 3D printer is known from WO 2018 / 086792 A1. The print head has a feed through which a raw material to be printed is fed to the print head. This raw material is melted and plasticized in the print head. This molten material is conveyed within the print head to an outlet opening, through which this material is applied to a printing area. DE 10 2019 219 083 A1 discloses a printing device for a 3D printer, comprising a metering device for melting and plasticizing a material to be printed and a discharge device for printing the material provided via the metering device. The metering device and the discharge device are arranged separately from one another and connectable to one another.

[0009] The invention is based on the object of providing a printing device for a 3D printer and a method for operating such a printing device, which enable an optimized printing process, whereby high-quality melt is to be provided in reproducible quality.

[0010] Disclosure of the invention

[0011] Within the scope of the invention, a printing device for a 3D printer was developed. This printing device comprises a dosing device for melting and plasticizing a material to be printed and a discharge device for printing the material provided via the dosing device. The dosing device and the discharge device are arranged separately from one another and can be connected to one another. The discharge device can be transported to the dosing device for receiving material. To connect the discharge device to the dosing device, a coupling point of the discharge device and a coupling point of the dosing device come into contact with one another. The dosing device has a coupling element at a dosing conveying opening which forms a channel. The material discharged via the dosing conveying opening can be conveyed to the coupling point of the coupling element.

[0012] According to the invention, the coupling element has a closing device in the region of the coupling point for opening and closing the channel.

[0013] The dosing device is particularly suitable for supplying raw material, which is melted and plasticized in the dosing device. Furthermore, the melted material can also be provided in metered quantities. The discharge device is suitable for dispensing material for producing a 3D body.

[0014] The dosing device and the discharge device are thus separated from each other. However, both devices can be connected to each other to accommodate material. Accordingly, the discharge device has a volume in which a certain amount of the molten material can be accommodated.

[0015] It was recognized that this offers advantages over print heads in which the dispensing device and the discharge device are provided together in a single print head. In particular, by separating the two devices, a smaller weight is moved, which essentially comprises the discharge device with the molten material. Accordingly, the dynamics of such a 3D printer are improved.

[0016] By separating the various functions, the corresponding device can be designed more optimally in terms of its functionality. For example, an actuator that exerts a force on the material in the dosing device no longer influences the discharge rate in the discharge device. This allows the actuators, for example, to be designed more cost-effectively and more effectively with regard to the desired result.

[0017] Separating the dosing device from the discharge device also has the advantage of improving material utilization. With a print head with a dosing device and discharge device, the introduced material must be consumed to prevent the molten material from subsequently solidifying in the discharge device. This sometimes results in not all of the material being used, resulting in waste. In contrast, only the required amount can be filled from the dosing device into the discharge device. This maximizes material utilization and reduces costs, enabling more economical production with this type of printing device.The locking device for opening and closing the channel in the area of ​​the coupling point of the coupling element enables sealing of the interface between the channel of the coupling element and the discharge device, thereby advantageously optimizing the filling process of the dosing device. In particular, this filling process, also called refill, can be optimized in terms of time because the material to be melted can be prepared in the dosing device during the printing process of the discharge device. The melting of the material, especially a material in granular form, can thus be optimized without resulting in cycle time losses for the overall system.

[0018] This is advantageously achieved by storing the melt in the dosing device or coupling element during the printing process of the discharge device. This allows for lower temperatures throughout the entire system, as rapid heating of the material is not necessary to optimize the cycle time of the entire system. The low temperature thus protects the material, which advantageously results in improved component quality, particularly improved adhesion between the layers.

[0019] Furthermore, energy can be saved, which can advantageously improve the economic efficiency of the overall system and reduce susceptibility to failure.

[0020] In a further development, the locking device is arranged on an actuator device for adjusting the locking device. The actuator device controls the locking device.

[0021] In a further development, the closing device is designed as a sliding element. The sliding element as a closing device thus advantageously enables drip-free and loss-free filling of the discharge device.

[0022] In a first embodiment of the invention, the coupling point of the discharge device is arranged at a nozzle of the discharge device. The nozzle is also suitable or intended for discharging the provided material or melt. The nozzle as the coupling point advantageously ensures that the discharge device does not require an additional opening for filling.

[0023] In a second embodiment of the invention, the coupling point of the discharge device is arranged laterally on the discharge device.

[0024] This advantageously prevents possible wear on the nozzle during filling.

[0025] In a further development, the coupling element has a heating element for tempering the material provided in the channel.

[0026] The heating element heats the provided material, or melt, or maintains a predetermined process temperature before and / or during the melt's feed to the discharge device, thereby advantageously achieving or maintaining a homogenized melt. The melt temperature can thus be advantageously adjusted in the coupling element. This provides an additional heating zone within the overall system.

[0027] In a further development, the coupling element has a pressure sensor for measuring the pressure of the material provided in the channel.

[0028] In a further development, the discharge device has a discharge piston which is driven by a servo motor so that the material can be discharged for printing.

[0029] A servo motor has the advantage of increasing the accuracy and reproducibility of the material discharge from the discharge device. This significantly improves the quality of the workpiece.

[0030] In a further development, the dosing device has a dosing piston for discharging the material in the dosing device. To ensure the high forces in the dosing device, the dosing piston for discharging the material is driven by a hydraulic system or an electric motor. The dosing piston is also movably arranged in the dosing device and exerts a force on the material in the dosing device in order to convey this material from the dosing device into the discharge device. In contrast to the discharge device, which requires high precision, sufficient forces can be provided in the dosing device. By separating the discharge device from the dosing device, each device can be optimized in terms of function.

[0031] To increase efficiency, multiple discharge devices can be provided, which alternately interact with a single dosing device to receive material. This means that only one dosing device is required for multiple discharge devices. Thus, a separate dosing device is not needed for each discharge device. This increases the utilization of the dosing device, thus increasing the efficiency of such a system.

[0032] The invention additionally provides a method for operating such a printing device.

[0033] Short description of the drawing

[0034] They show:

[0035] Fig. 1 shows an example of a printing device during filling of a discharge device according to the prior art;

[0036] Fig. 2 shows an example of a printing device with several discharge devices arranged in different pressure chambers according to the prior art;

[0037] Fig. 3 shows a printing device according to the invention of a first embodiment in a first operating state; Fig. 4 shows the printing device according to the invention of the first embodiment in a second operating state and

[0038] Fig. 5 shows a printing device according to the invention of a second embodiment in a first operating state.

[0039] Examples of implementation

[0040] Fig. 1 shows an example of a printing device 10 for providing a material 38 to be printed from the prior art during filling of a discharge device 14. Fig. 1 is a sectional view of the device 10. In addition to the discharge device 14, the printing device 10 has a metering device 18. The metering device 18 is formed from a base body 22 on which a filling funnel 26 is arranged. A raw material 30, which is in solid form, in particular as granules, can be filled into the filling funnel 26. The filling funnel 26 is directly connected to a metering chamber 34 formed by the base body 22. In this metering chamber 34, the raw material 30 is melted and plasticized to form a printable material 38.

[0041] The dosing chamber 34 has a lateral dosing piston opening 42. A dosing piston 46 is arranged in this dosing piston opening 42 and projects into the dosing chamber 34. A dosing piston force FD can be applied to the material 38 in the dosing chamber 34 via the dosing piston 46, so that the material can be pressed toward a dosing delivery opening 50 opposite the dosing piston opening 42.

[0042] At the metering conveying opening 50, the metering device 18 has a coupling element 54 which forms a channel 58 so that the material 38 discharged via the metering conveying opening 50 can be conveyed to a coupling point 62 of the coupling element 54. The discharge device 14 is arranged at the coupling point 62 so that this discharge device 14 can receive the molten material 38, or the melt. The discharge device 14 has a discharge body 66 which forms a discharge chamber 70 in which molten material 38 can be received. At an end of the discharge body 66 connected to the coupling point 62, a nozzle 74 is formed through which the molten material 38 can be received. The material 38 is also applied to a workpiece (not shown) through this nozzle 74.

[0043] Within the discharge chamber 70, a discharge piston 78 is arranged, via which the material 38 can be discharged.

[0044] Fig. 2 shows an example of a prior art device 100 with multiple discharge devices 14 arranged in different pressure chambers 102. A different workpiece can be manufactured in each pressure chamber 102. A discharge device 14 is arranged in each pressure chamber 102, each of which is housed in a print head body 106. The respective discharge devices 14 are movable via said discharge devices.

[0045] The device 100 has a transport system 86. Accordingly, several discharge devices 14 can be connected to one another via a single transport system 86. This can improve the utilization of the device 100.

[0046] Fig. 3 shows a printing device 10 according to the invention of a first embodiment in a first operating state, this operating state representing a filling process of a discharge device 14 by a dosing device 18. The printing device 10 for a 3D printer comprises the dosing device 18 for melting and plasticizing a material 38 to be printed and the discharge device 14 for printing the material 38 provided via the dosing device 18. The dosing device 18 and the discharge device 14 are arranged separately from one another and can be connected to one another, wherein the discharge device 14 for receiving material 38 can be transported to the dosing device 18 via a transport device 87 and for connecting the discharge device 14 to the dosing device 18, a coupling point 61 of the discharge device 14 and a coupling point 62 of the dosing device 18 come into contact with one another.The dosing device 18 has a coupling element 54 at a dosing feed opening 50, which forms a channel 58, wherein the material 38 discharged via the dosing feed opening 50 can be conveyed to the coupling point 62 of the coupling element 54. The dosing device 18 has a dosing piston 46 for discharging the material 38 in the dosing device 18, which is driven by a hydraulic system or an electric motor.

[0047] The coupling element 54 has a closing device 91 for opening and closing the channel 58 in the region of the coupling point 62. The closing device 91, designed as a sliding element, is arranged on an actuator device 90 for adjusting the closing device 91. The sliding element 91 projects from the actuator device 90 through the coupling element 54, projecting into the channel 58.

[0048] In the embodiment shown here, the coupling point 62 of the discharge device 14 is arranged on a nozzle 74 of the discharge device 14.

[0049] The sliding element 91 has an end 92 arranged within the channel 58. The process state shown here shows that the coupling point 62 of the coupling element 54 rests against the coupling point 61 of the discharge device 14 and establishes a connection.

[0050] The sliding element 91, or the linear slide, is opened by means of the actuator device 90, or the actuator, at a set time, whereby the previously plasticized material 38 can be pressed into the discharge device 14. This occurs through the pressure exerted by the dosing piston 46 of the dosing device 18.

[0051] The material 38 located in the channel 58, or the melt, can be pressed through the connection into the discharge device 14. The discharge device 14' shown in dashed lines represents a possible printing position during a printing process.

[0052] After filling the discharge device 14 by the dosing device

[0053] 18, the channel 58 is closed in the area of ​​the coupling point 62 by means of the sliding element 91. Both devices 14, 18 can then carry out a pressure relief. This allows the interfaces 61,

[0054] 62 ensure that there are no drips after filling.

[0055] The coupling element 54 has a heating element 98 for controlling the temperature of the material 38 provided in the channel 58. The heating element 98 heats the material 38 located in the channel 58 or maintains it at a target temperature required for printing preparation. The coupling element 54 has a pressure sensor 80 for measuring the pressure of the material 38 provided in the channel 58. The pressure sensor 80 determines the melt pressure within the channel 58, whereby the evaluation of the pressure can be used for process optimization.

[0056] Fig. 4 shows the printing device 10 according to the invention of the first embodiment in a second operating state, this operating state representing a printing process of the discharge device 14.

[0057] The structure is analogous to that shown in Fig. 3, with the dosing unit 14, transported by the transport device 87, in a printing position. The discharge device 14' shown in dashed lines represents a possible filling position, as described in Fig. 3.

[0058] The sliding element 91 rests with its end 92 in the area of ​​the coupling point 62 of the coupling element 54 and closes it. As a result, no material 38 or melt can escape from the channel 58 of the coupling element 54. The channel 58 is thus closed.

[0059] The discharge device 14 has a discharge piston 78, which can be driven by a servo motor and thus the material 38 can be discharged for printing.

[0060] While the printing is being carried out by the discharge device 14, the dosing device 18 can prepare the channel 58 of the coupling element 54 with new material 38 or with new melt. Fig. 5 shows a second embodiment of a printing device 10 according to the invention in an operating state, this operating state representing a printing process of the discharge device 14. The structure and mode of operation are essentially analogous to the first embodiment of the invention. The difference is that the coupling point 61, 61' of the discharge device 14 is arranged laterally on the discharge device 14.

[0061] Here, too, the dosing device 18 and the discharge device 14 are arranged separately from one another and can be connected to one another, wherein the discharge device 14 can be transported to the dosing device 18 via the transport device 87 to receive material 38, and the coupling point 61 of the discharge device 14 and the coupling point 62 of the dosing device 18 can come into contact with one another to connect the discharge device 14 to the dosing device 18. In this embodiment, the coupling point 62 of the dosing device 54 is arranged in the pressure direction of the dosing piston 46. The dosing device 18 has the coupling element 54 at the dosing conveying opening 50, which forms the channel 58, wherein the material 38 discharged via the dosing conveying opening 50 can be conveyed to the coupling point 62 of the coupling element 54.The dosing device 18 has the dosing piston 46 for discharging the material 38 in the dosing device 18, which is driven by a hydraulic system or an electric motor.

[0062] The coupling element 54 has, in the region of the coupling point 62, the closing device 91 for opening and closing the channel 58. The closing device 91, designed as a sliding element, is arranged on the actuator device 90 for adjusting the closing device 91. The sliding element 91 protrudes from the actuator device 90 through the coupling element 54, projecting into the channel 58.

[0063] The coupling element 54 has a heating element 98 for controlling the temperature of the material 38 provided in the channel 58. The heating element 98 heats the material 38 located in the channel 58 or maintains it at a target temperature required for printing preparation. The coupling element 54 has the pressure sensor 98 for measuring the pressure of the material 38 provided in the channel 58. The pressure sensor 98 determines the melt pressure within the channel 58; the evaluation of the pressure can be used for process optimization.

[0064] The discharge device 14' shown in dashed lines with its laterally arranged coupling point 61' represents a possible filling position.

[0065] The sliding element 91 rests with its end 92 in the area of ​​the coupling point 62 of the coupling element 54 and closes it. This prevents any material 38 or melt from escaping from the channel 58 of the coupling element 54. The channel 58 is thus closed.

[0066] The discharge device 14 has a discharge piston 78, which can be driven by a servo motor and thus discharges the material 38 for printing. The laterally arranged coupling point 61 of the discharge unit 14 is closed after filling and is only opened again for filling after contact with the coupling point 62 of the coupling element 54.

[0067] Fig. 3 to Fig. 5 show the printing device 10 and also describe a method for operating the printing device 10, wherein the discharge device 14 has consumed the entire material 38, or the volume of the melt, during printing. The discharge device 14 must then be refilled, for which purpose the discharge device 14 is coupled to the metering device 18 via the coupling element 54. The already preheated material 38, or granules, are then plasticized in one batch and filled into the discharge device 14 via the channel 58 of the coupling element 54. The printing device 10 according to the invention is capable of preparing and plasticizing the granules simultaneously during printing. If the coupling points 61, 62 or the interface are coupled, the closing device 91 or the linear slide opens the channel 58 to the discharge device 14 and the melt 38 can flow into it.

[0068] Once the discharge device 14 is filled, the channel 58 can be closed by the closing device 91 or the linear slide. Thus, the coupling points 61, 62, or the interface, can be disconnected. During the execution of the method, the pressure sensor 80 can be used to adjust the ideal melt pressure within the channel 58 or to prepare the melt 38.

[0069] The printing device 10 is arranged modularly within a possible 3D printing system. For filling or refilling, the printing process is briefly interrupted, and the discharge device 14 is fed to the dosing device 18.

[0070] Thanks to the integrated heater 98 within the coupling element 54, the interruption during the filling process can be kept very short. The extended sealing function provided by the closing device 91 allows the melt 38 to be held within the coupling element 54 and the dosing device 18, with the melt 38 already fully plasticized and homogenized upon coupling to the discharge device 14. Likewise, the closing device 91, or the linear slide, and its sealing function, enable drip-free and loss-free filling.

[0071] Furthermore, in the discharge device 14, after filling and closing the channel 58, a target pressure of the melt 38 within the discharge device 14 can be set by moving the discharge piston 78.

Claims

Claims 1. A printing device (10) for a 3D printer, comprising a dosing device (18) for melting and plasticizing a material (38) to be printed, and a discharge device (14) for printing the material (38) provided via the dosing device (18), wherein the dosing device (18) and the discharge device (14) are arranged separately from one another and connectable to one another, wherein the discharge device (14) is transportable to the dosing device (18) for receiving material (38), and for connecting the discharge device (14) to the dosing device (18), a coupling point (61) of the discharge device (14) and a coupling point (62) of the dosing device (18) come into contact with one another, wherein the dosing device (18) has a coupling element (54) at a dosing conveying opening (50), which coupling element forms a channel (58),wherein the material (38) discharged via the metering conveying opening (50) can be conveyed to the coupling point (62) of the coupling element (54), characterized in that the coupling element (54) has a closing device (91) for opening and closing the channel (58) in the region of the coupling point (62).

2. Printing device (10) according to claim 1, characterized in that the closing device (91) is arranged on an actuator device (90) for adjusting the closing device (91).

3. Printing device (10) according to one of the preceding claims, characterized in that the closing device (91) is designed as a sliding element.

4. Printing device (10) according to one of the preceding claims, characterized in that the coupling point (62) of the discharge device (14) is arranged on a nozzle (74) of the discharge device (14).

5. Printing device (10) according to one of claims 1 to 3, characterized in that the coupling point (62) of the discharge device (14) is arranged laterally on the discharge device (14).

6. Printing device (10) according to one of the preceding claims, characterized in that the coupling element (54) has a heating element (98) for tempering the material (38) provided in the channel (58).

7. Printing device (10) according to one of the preceding claims, characterized in that the coupling element (54) has a pressure sensor (98) for measuring the pressure of the material (38) provided in the channel (58).

8. Printing device (10) according to one of the preceding claims, characterized in that the discharge device (14) has a discharge piston (78) which is driven by a servo motor, so that the material (38) can be discharged for printing.

9. Printing device (10) according to one of the preceding claims, characterized in that the dosing device (18) has a dosing piston (46) for discharging the material (38) in the dosing device (18), which is driven by a hydraulic system or an electric motor.

10. Method for operating a printing device (10) according to one of the preceding claims.

Images