3D printer for printing an object and a method for operating a 3D printer

Abstract

The invention relates to a 3D printer (1) for printing an object (2), comprising an X, Y, Z axis system (3) and two print heads (10, 11) with nozzles (12, 13) for dispensing a printable material. The invention is characterized in that the first (10) and the second print head (11) are arranged on a bridge (30) which can be moved via guide rails (80, 81) in the direction of a Y-axis (20) and the 3D printer (1) has a separate closing device (50) for each print head (10, 11) for closing the nozzles (12, 13) during a filling process (300) of the print heads (10, 11). The invention further relates to a method (100) for operating a 3D printer (1) according to the invention, wherein the two print heads (10, 11) print alternately, the second print head (11) taking over the starting position of the first print head (10) in order to continue a printing process (400) when it switches to a filling process (300) to fill the first print head (10).

Description

[0001] The present invention relates to a 3D printer for printing an object and a method for operating a 3D printer. State of the art

[0002] The state of the art in 3D printing encompasses various technologies and machine configurations that aim to create objects by depositing material layer by layer. Granular 3D printers, which use granular materials, are particularly well-known.

[0003] From DE 102016222306 A1, a printhead is known in which a granulate is plasticized via a piston and a heated section. When the piston presses on the granulate, it is compacted and conveyed to a plasticization zone in the lower part of the printhead.

[0004] These printers typically use piston extruders that melt and deposit the granules. A common problem with these printers is the need to interrupt the printing process to refill and melt new granules. These interruptions result in visible marks on the printed object and compromise the part quality. Furthermore, many 3D printers are heavy and unwieldy due to their design and motor arrangement, leading to higher purchase costs and lower efficiency.

[0005] German patent DE 102022213030 A1 discloses a 3D printer for printing a material with a print head and a nozzle, wherein the nozzle can be closed, at least partially, by a closing device during a compaction process of the material. The closing device comprises an elastically yielding closing means for closing the nozzle, in particular a nozzle opening.

[0006] The present invention therefore aims to provide a 3D printer and a method for operating a 3D printer, wherein these should enable optimal printing and filling processes that deliver better component quality and can carry out the printing process or print job with few short interruptions. Disclosure of the invention

[0007] Within the scope of the invention, a 3D printer for printing an object and a method for operating a 3D printer were developed.

[0008] The invention comprises a 3D printer for printing an object, comprising an X, Y, Z axis system and two print heads with nozzles for dispensing a printable material. According to the invention, the first and second print heads are arranged on a bridge that is movable along guide rails in the direction of a Y axis, and the 3D printer has a separate closing device for each print head for closing the nozzles during a filling process of the print heads.

[0009] One advantage of the two printheads is the increased printing speed and efficiency. Using both printheads in parallel or alternately allows for faster object production. The arrangement of the printheads on a movable bridge enables flexible printing across the entire print area. Separate sealing devices for each printhead prevent material leakage during the filling process, thus minimizing material waste and contamination. Closing the nozzles during the filling process ensures clean and uninterrupted filling. This allows for independent filling and sealing, increasing the flexibility and efficiency of the printing process. For example, one printhead can be filled while the other continues printing.

[0010] In one embodiment, the locking devices are arranged on the guide rails.

[0011] The arrangement of the locking devices on the guide rails offers the advantage of a compact design. This advantageously keeps the installation space around the print head and bridge clear, increasing design flexibility and the bridge's range of motion.

[0012] In another embodiment, the locking devices are arranged on the bridge.

[0013] It is advantageous that the locking devices move along with the bridge and are therefore always near the printheads, which reduces the reaction time when closing.

[0014] In another embodiment, the locking devices are arranged on the printheads.

[0015] One advantage of arranging the locking devices directly on the printheads is the direct and individual control of each printhead.

[0016] In a further training course, the locking devices are arranged to pivot on the print heads.

[0017] The pivoting arrangement of the locking devices on the printheads is advantageous because it allows for simple and quick operation of the locking mechanism. Another advantage is the compact design of the pivoting mechanism.

[0018] In a further training, the closure device features an elastically yielding closure element.

[0019] One advantage of the elastically yielding sealing compound is the reliable sealing of the nozzles. Its elasticity allows for a good fit to the nozzle geometry and ensures a reliable seal, even with slight tolerance deviations. The elasticity also advantageously reduces wear on the nozzles.

[0020] In this advanced training, the X-axis can be controlled independently of the Y-axis. Independent control of the X and Y axes offers the advantage of optimized printhead movement and thus higher printing speeds. Complex geometries can be printed more efficiently because the printheads can be positioned independently of each other in the X and Y directions.

[0021] Furthermore, the invention comprises a method for operating a 3D printer according to the invention, wherein the two print heads print alternately, the second print head taking over the starting position of the first print head in order to continue a printing process when the latter switches to a filling process to fill the first print head.

[0022] One advantage of this method is the continuous printing process during the printhead refilling process. Alternating printing and position changes minimize printing time and increase productivity. The absence of printing pauses ensures an uninterrupted printing process.

[0023] The procedure for operating a 3D printer may further include the following steps: - Starting a printing process; - Performing a filling process of the first printhead and / or the second printhead; - Printing one or more objects, with both printheads able to print alternately, the second printhead taking over the starting position of the first printhead to continue printing when the latter switches to a refilling process to refill the first printhead or vice versa; - Ending the printing process when both printheads are empty and no further refills are required.

[0024] The process for operating a 3D printer includes essential steps such as starting a print job, filling the print heads, printing objects by alternating between the print heads, and ending the print job when both print heads are empty. The advantages of this method lie in its continuous printing capability, as the second print head takes over the work of the first when it is being refilled, and vice versa. This minimizes downtime and increases the efficiency of the printing process. Furthermore, the print job ends automatically when no further refills are required, simplifying operation and optimizing material consumption.

[0025] Further measures improving the invention are described in more detail below, together with a description of preferred embodiments of the invention, with reference to figures. Brief description of the drawing

[0026] They show: Fig. 1 a schematic representation of a first embodiment of a 3D printer according to the invention; Fig. 2 a flowchart of a method for operating a 3D printer according to the invention; Fig. 3 a schematic representation of the first embodiment of a 3D printer according to the invention; Fig. 4 a schematic representation of a second embodiment of a 3D printer according to the invention; Fig. 5 a schematic representation of a third embodiment of a 3D printer according to the invention and Fig. 6 a schematic representation of a fourth embodiment of a 3D printer according to the invention. Examples of implementation

[0027] Fig. Figure 1 shows a schematic representation of a first embodiment of a 3D printer 1 according to the invention for printing an object 2.

[0028] The 3D printer 1 comprises an X, Y, Z axis system 3 and two print heads 10, 11 with nozzles 12, 13 for extruding a printable material to print an object 2. The first 10 and the second 11 print heads are arranged on a bridge 30 that is movable along guide rails 80, 81 in the direction of a Y-axis 20. The 3D printer 1 has a separate closing device 50, 51, 52 for each print head 10, 11 for closing the nozzles 12, 13 during a filling process of the print heads 10, 11. The closing device 50 functions as a filling station or refill station for the respective print head 10, 11. In this configuration, the closing devices 50, 51, 52 are arranged on the bridge 30. The following describes the basic structure and technical principle of the 3D printer 1, which is applicable to all embodiments.

[0029] The X, Y, Z axis system 3 forms a drive system 3, or a drive device 3, for moving the print heads 10, 11 in the X and Y directions and a build plate 4 in the Z direction, whereby the object 2 to be printed is printed onto the build plate 4. The directions of the X, Y, Z axis system 3 are shown by an X, Y, Z axis 5.

[0030] The Y-axis 20 can be driven simultaneously by two motors 40 and 41 to achieve improved positional accuracy. The motors 40 and 41 can be driven in parallel to prevent deflection caused by dynamic movement of the bridge 30. The X-axis 25 can be controlled independently of the Y-axis 20.

[0031] The printheads are moved 10, 11 via guide rails 80, 81 and belt drives 82, 83, with the belt drives 82, 83 guided by pulleys 92, 93 to ensure precise positioning. The guide rails 80, 81 form bridge shoulders on which the bridge 30 is mounted in the Y-direction. The belt drives 82, 83 move the printheads 10, 11 in the X-direction 25, with motor 60 moving the first printhead 10 via the first belt drive 82 and motor 61 moving the second printhead 11 via the second belt drive 83. The motors 40, 41 for the Y-axis 20 are mounted on a machine frame 70 to reduce the moving mass, and the bridge 30 is thus designed with optimized weight to increase the repeatability of the printing process.

[0032] The two printheads 10, 11 can print alternately to minimize interruptions during a printing process, with the second printhead 11 taking over the starting position of the first printhead 10 to continue the printing process when it switches to a refill mode to fill the first printhead 10.

[0033] The printheads 10, 11 can be moved independently of each other along the X-axis 25, and it is also possible to print in parallel with both printheads 10, 11 using different materials.

[0034] The Y-axis 20 can also be controlled by motors 40, 41 on one side only, with the other motor remaining stationary and supported on the machine frame 70 to minimize any possible deflection of the bridge 30 at higher dynamics.

[0035] The motors 60, 61, and the actuators for the X-axis 25 are arranged on the machine frame 70, allowing the bridge 30 to move with less weight. This enables not only the bridge 30, but also the entire drive unit 3 to be designed lighter, further increasing the system's positional accuracy.

[0036] The print heads 10 and 11 are moved primarily by the motor 60, which drives the print head 10, or extruder, along the X-axis 25 via the belt 82 and the pulleys 94, 96, 92, and 98. The motor 61 drives the second print head 11, or extruder, along the X-axis 25 via the belt 83 and the pulleys 95, 97, 93, and 99.

[0037] Motors 40 and 41 move the bridge 30 along the Y-direction 20 and, to achieve better positional accuracy, are generally driven in parallel, thus preventing deflection due to the dynamic movement of the bridge 30. The respective belt is driven by the respective motor 40, 41 and deflected via pulleys 90, 91.

[0038] Because the motors 60 and 61 are not located on the bridge 30, they must always move along with the bridge 30 when it is moved along the Y-axis 20 in order to compensate for the position of the respective printheads 10, 11.

[0039] As an alternative function, the inventive design of the 3D printer 1 also offers the possibility of printing simultaneously with two print heads 10, 11, in particular with the same or different starting materials.

[0040] Fig. Figure 2 shows a flowchart of a method 100 for operating the 3D printer 1 according to the invention, wherein the 3D printer 1 comprises an X, Y, Z axis system 3, a first print head 10 and a second print head 11, and the method 100 comprises the following steps: - Starting 200 of a printing process; - Execute 300 of a filling process of the first printhead 10 and / or the second printhead 11; - Printing 400 of one or more objects 2, wherein both printheads 10, 11 can print alternately, the second printhead 11 taking over the starting position of the first printhead 10 to continue printing 400 when it switches to a filling process 300 to fill the first printhead 10 or vice versa; - End the printing process when both printheads 10, 11 are empty and no further refills are required.

[0041] Furthermore, the method 100 includes setting an operating temperature of the printheads 10, 11 during the start-up 200 210. In further developments of the method, it is advantageous if the printheads 10, 11 are emptied during the start-up 200, or the start-up process.

[0042] Furthermore, during the filling process 300, a decision is made as to which printhead 10, 11 should be operated, and the filling process 300 is automatically activated if the fill level of the respective printhead 10, 11 falls below a predetermined value during printing 400.

[0043] The following describes additional steps that can be performed in Method 100 to operate the 3D printer 1 advantageously. Method 100 for operating the 3D printer 1 with two printheads 10, 11 includes, in particular, the filling process 300 (refill mode) of the printheads 10, 11. The process begins with starting 200 the printing process, or the print job. First, it is checked whether the operating temperature has been reached. If this is not the case, the temperature is adjusted 210 until the required operating temperature is reached.

[0044] The system then checks whether the corresponding printhead(s) 10 and 11 are empty. If printhead 10 or 11 is not empty, printing process 400 continues with both printheads 10 and 11. However, if printhead 10 or 11 is empty, refill mode 300 is activated. A decision is then made as to which of the two printheads 10 or 11 (first printhead 10 or second printhead 11) should be refilled. Depending on which printhead 10 or 11 needs refilling, the corresponding refill mode 300 is activated.

[0045] For the first printhead 10 to undergo refill mode 300, the first printhead 10 moves to its printing position. If the first printhead 10 is not ready to print, a refill time for the first printhead 10 is determined based on current process parameters. As soon as this time is reached, refill mode 300 is started for the first printhead 10. If the first printhead 10 is ready to print, the printing process 400 continues with the first printhead 10. The system checks whether the print job is complete. If the print job is not complete, it checks whether the first printhead 10 is empty. If the first printhead 10 is empty, refill mode 300 is reactivated for the first printhead 10. If the first printhead 10 is not empty, the printing process 400 continues with the first printhead 10.

[0046] For refill mode 300 of the second printhead 11, the second printhead 11 moves to its printing position. If the second printhead 11 is not ready to print, a refill time for the second printhead 11 is determined based on current process parameters. As soon as this time is reached, refill mode 300 is started for the second printhead 11. If the second printhead 11 is ready to print, the printing process 300 continues with the second printhead 11. The system checks whether the print job is complete. If the print job is not complete, it checks whether the second printhead 11 is empty. If the second printhead 11 is empty, refill mode 300 is reactivated for the second printhead 11. If the second printhead 11 is not empty, the printing process 400 continues with the second printhead 11.

[0047] Print job 400 continues if refill mode 300 is complete. The process then returns to printing with both printheads 10 and 11. The system continuously checks whether the print job is finished. Once the print job is complete, print job 500 is terminated.

[0048] This procedure 100 ensures that the printing process continues uninterrupted by having the second printhead 11 take over the printing position of the first printhead 10 when the latter switches to refill mode 300. This guarantees uninterrupted production and optimizes the refilling process 300 of the printheads 10 and 11.

[0049] Fig. Figure 3 shows a schematic representation of the first embodiment of the 3D printer 1 according to the invention, wherein the basic structure is shown in Fig. Figure 1 describes the following: The closing devices 50, 51, 52 are arranged on the bridge 30. Furthermore, each closing device 50, 51, 52 has an elastically yielding closing element 511, 521. The elastic closing element 511, 521 can comprise a pressure medium made of an elastic material, for example, a ball with a spring, wherein the ball is suitable for closing the nozzles 12, 13.

[0050] In this version, the filling position, or refill position, is fixed or immovable in the X-direction 25, thus enabling the printing heads 10, 11 to be filled with granules.

[0051] Fig. Figure 4 shows a schematic representation of a second embodiment of a 3D printer 1 according to the invention, wherein the basic structure is shown in Fig. 1 is described. In this embodiment, the locking devices 50, 53, 54 are arranged on the printheads 10, 11, wherein the locking devices 53, 54 are pivotably arranged on the printheads 10, 11.

[0052] Furthermore, the closure devices 50, 53, 54 each have an elastically yielding closure element 531, 541. The elastic closure element 531, 541 can comprise a pressure medium made of an elastic material, for example, a ball with a spring, wherein the ball is suitable for closing the nozzles 12, 13. An elastically yielding plate can also be pivotably or rotatably arranged on the printhead 10, 11 to close the nozzle 12, 13.

[0053] Fig. Figure 5 shows a schematic representation of a third embodiment of a 3D printer 1 according to the invention, wherein the basic structure is shown in Fig. As described in Figure 1, in this embodiment the locking devices 50, 55, 56 are arranged on the guide rails 80, 81, each being located at the end of the guide rails 80, 81, outside the pressure area. Furthermore, the locking devices 50, 55, 56 each have an elastically yielding locking element 551, 561. The elastic locking element 551, 561 can comprise a pressure medium made of an elastic material, for example, a ball with a spring, the ball being suitable for closing the nozzles 12, 13. In this embodiment, the locking devices 55, 56 are fixed locally to the Y-axis 20, which necessitates decoupling the respective printhead 10 to be filled from the axis system 3 to allow printing of the other printhead 11.

[0054] Fig. Figure 6 shows a schematic representation of a fourth embodiment of a 3D printer 1 according to the invention, wherein the basic structure is shown in Fig. 1 is described. In this embodiment, the closing devices 50, 57, 58 are arranged on the guide rails 80, 81, wherein, for example, a sheet is attached over the entire length of the guide rail 80, 81, whereby the respective nozzle 12, 13 is closed by passing over it. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 102016222306 A1

[0003] DE 102022213030 A1

[0005]

Claims

[1] 3D printer (1) for printing an object (2), comprising an X, Y, Z axis system (3) and two print heads (10, 11) with nozzles (12, 13) for ejecting a printable material, characterized by , that the first (10) and the second print head (11) are arranged on a bridge (30) which can be moved via guide rails (80, 81) in the direction of a Y-axis (20) and the 3D printer (1) has a separate closing device (50) for each print head (10, 11) for closing the nozzles (12, 13) during a filling process (300) of the print heads (10, 11). [2] 3D printer (1) according to claim 1, characterized by , that the locking devices (50, 55, 56, 57, 58) are arranged on the guide rails (80, 81). [3] 3D printer (1) according to claim 1, characterized by , that the locking devices (50, 51, 52) are arranged on the bridge (30). [4] 3D printer (1) according to claim 1, characterized by, that the locking devices (50, 53, 54) are arranged on the printheads (10, 11). [5] 3D printer (1) according to claim 4, characterized by , that the locking devices (50, 53, 54) are pivotably arranged on the printheads (10, 11). [6] 3D printer (1) according to any one of the preceding claims, characterized by , that the closure device (50, 51, 52, 53, 54, 55, 56) has an elastically yielding closure means (511, 521, 531, 541, 551, 561). [7] 3D printer (1) according to any one of the preceding claims, characterized by , that the X-axis (25) can be controlled independently of the Y-axis (20). [8] Method (100) for operating a 3D printer (1) according to any one of the preceding claims, characterized by, that the two printheads (10, 11) print alternately, with the second printhead (11) taking over the starting position of the first printhead (10) to continue a printing process (400) when it switches to a filling process (300) to fill the first printhead (10).

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