Apparatus and method for additive manufacturing of three-dimensional workpieces
By introducing a circulating air system and a z-axis integrated exhaust device into the additive manufacturing apparatus, the problems of uneven temperature in the build chamber and thermal deformation were solved, improving workpiece quality and manufacturing efficiency while reducing maintenance difficulty.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ROBERT BOSCH GMBH
- Filing Date
- 2021-11-22
- Publication Date
- 2026-07-07
AI Technical Summary
In additive manufacturing, the shrinkage of thermoplastic materials during cooling leads to deviations in workpiece dimensions, and the uneven temperature regulation of the build chamber in existing 3D printers causes thermal deformation and cold bridging problems, affecting workpiece quality.
A device with a circulating air system is used, and the air intake and exhaust devices are integrated in the z-axis system to achieve uniform temperature regulation of the build chamber. Combined with the adjustment of the xy-axis system and z-axis system, it ensures that the gaseous fluid is evenly distributed in the build chamber and avoids the formation of cold and hot spots.
This achieves uniform indoor temperature and reduced workpiece deformation, improving workpiece manufacturing efficiency, reducing costs, and simplifying the maintenance process.
Smart Images
Figure CN116669931B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to an apparatus for additive manufacturing of three-dimensional components having the features of the preamble of claim 1. The invention also relates to a method for additive manufacturing of three-dimensional components according to claim 9. Background Technology
[0002] In additive manufacturing, or 3D printing, liquid or solid materials are layered and built into a three-dimensional workpiece. For example, thermoplastic materials, especially thermoplastic plastics, can be used, which are first liquefied by heating. The liquid material is then selectively applied to the location where the workpiece is to be formed. The material solidifies again by cooling.
[0003] This device includes a printhead in which raw materials are prepared for printing. Furthermore, a shaft system for generating relative motion between the printhead and the work surface on which the object is to be formed is known. Here, it is possible to move either only the printhead, only the work surface, or both the printhead and the work surface.
[0004] Some thermoplastic materials tend to shrink upon cooling. This shrinkage leads to dimensional deviations in the manufactured workpiece. To counteract this, 3D printers with heated build chambers are known, allowing the temperature of the build chamber to be kept as constant as possible during the printing process. However, elements, such as those extending into the build chamber, exist and thus alter the temperature structure. Especially when these elements are not temperature-regulated, cold bridges can occur, leading to uneven temperature control within the build chamber and potentially causing thermal deformation in the workpiece or component to be manufactured. Therefore, due to the thermal deformation that has already occurred, it is impossible to build the workpiece or component without defects. Summary of the Invention
[0005] The object of the present invention is to provide an apparatus that makes additive manufacturing of three-dimensional workpieces made of thermoplastic materials more efficient and, consequently, more cost-effective.
[0006] This objective is achieved by the apparatus for additive manufacturing of three-dimensional workpieces according to the invention, having the features of claim 1, and the method for additive manufacturing of three-dimensional workpieces according to the invention, as described in claim 9.
[0007] The proposed apparatus for additive manufacturing of three-dimensional workpieces includes: a build chamber, at least one printhead, a receiving device for receiving the three-dimensional workpiece, a circulating air system for temperature control and transport of a gaseous fluid, and an adjustment device including an xy-axis system and a z-axis system, the xy-axis system having a printhead receiving section. According to the invention, the circulating air system has a device for temperature control and transport of the gaseous fluid, an air intake device with at least two air intake openings connected to the build chamber, and an exhaust device, wherein the exhaust device is integrated into the z-axis system and arranged to be adjustable by means of the z-axis system.
[0008] Devices used for additive manufacturing of three-dimensional workpieces are also known as 3D printers or printers.
[0009] The optimized temperature control of the build chamber is advantageously achieved through a circulating air system with means for temperature control and transport of gaseous fluids. Therefore, the apparatus for additive manufacturing of three-dimensional workpieces according to the invention resists uneven temperature control in the build chamber and ensures a more uniform temperature structure throughout the build chamber.
[0010] The gaseous fluid can be air or, advantageously, a protective gas.
[0011] Furthermore, the circulating air system includes a device for temperature control and transport of the gaseous fluid, by which the gaseous fluid is advantageously heated and transported into the circulating air system. The gaseous fluid flows into the build chamber through the inlet device, fills the build chamber, flows around the workpiece to be manufactured, and then flows through the exhaust device integrated into the z-axis system. Thus, the circulating air system of the apparatus for additive manufacturing of three-dimensional workpieces advantageously ensures a uniform temperature structure inside the build chamber.
[0012] Furthermore, the apparatus for additive manufacturing of three-dimensional workpieces according to the invention combines adjustment of the z-height of the axis with the output of process air for the air circulation system. Due to this modified ventilation system, the temperature of the build chamber and the workpiece, or component, is regulated to a more constant level. Here, temperature regulation is advantageously significantly more uniform, thereby resulting in less deformation in the workpiece or component.
[0013] In particular, it has enabled an increase in the efficiency of the entire heating system of the apparatus used for additive manufacturing of three-dimensional workpieces. This is achieved, in particular, by preventing cold or hot spots inside the build chamber, thereby advantageously reducing workpiece deformation.
[0014] In the improved design, the exhaust device has a gap within the housing of the z-axis system.
[0015] This allows airflow to be guided through the z-axis, thereby also regulating the temperature of that z-axis. Therefore, the previously unregulated z-axis advantageously does not affect the overall temperature regulation of the construction chamber. Furthermore, it advantageously allows the use of only one central z-axis.
[0016] In the improved design, the gap in the exhaust device is located below the receiving device.
[0017] In a preferred improvement, the air intake device has a channel and a connection device with an air intake opening, wherein gaseous fluid can be transported from the device for temperature control and transport to the build chamber via the air intake device.
[0018] This allows for the possibility of adjusting the inflow and outflow airflow at the intake and exhaust devices, which can be advantageously adjusted according to the components.
[0019] In the improved design, the air intake opening of the air intake device is positioned above the workpiece and the z-axis system.
[0020] In the improved design, the air intake opening of the air intake device includes a valve.
[0021] Better airflow control can be advantageously achieved through adjustable intake and exhaust slits or valves. A key advantage here is the central exhaust or central suction of gaseous fluid or process air below the build chamber, thus achieving a uniformly temperature-controlled airflow while simultaneously adjusting the height of the receiving device or substrate carrier for the workpiece. Previously, for example, there were five through-holes at the bottom of the build chamber; according to the embodiment of the invention, only one through-hole is still needed. Simultaneously, the Z-axis telescopic shaft is temperature-controlled, thus advantageously eliminating cold bridges. Cables for sensors and wiring, or cables for heating the build plate, can also be laid, for example, in the housing or ventilation shaft. This combination of functions advantageously achieves a significantly more cost-effective implementation and improves access to and maintenance of the build chamber. This advantageously allows, for example, the entire build chamber to be pulled out of the printer. For this purpose, for example, the substrate carrier is removed and the Z-axis, or telescopic shaft, is moved out of the build chamber.
[0022] Furthermore, the overall efficiency of temperature regulation in the build chamber is improved because less heat is output due to the change in the z-axis. Additionally, the arrangement of the air inlets and outlets results in a more even distribution of introduced heat, thereby preventing cold or hot spots inside the build chamber. Moreover, as mentioned earlier, no other openings are required in the build chamber, thus simplifying its replacement during maintenance.
[0023] In the improved design, the air intake opening of the air intake device is adapted to accommodate a replaceable air intake mold, wherein the air intake mold has a different geometry, or opening geometry, depending on the geometry of the workpiece.
[0024] According to the present invention, a method for additive manufacturing of three-dimensional workpieces using the apparatus according to any of the foregoing embodiments is proposed. Attached Figure Description
[0025] Other advantages are derived from the accompanying drawings and the description of the embodiments.
[0026] This is shown here:
[0027] Figure 1 is an illustration of an apparatus for additive manufacturing of three-dimensional workpieces according to the prior art;
[0028] Figure 2 This is a diagram of an apparatus for additive manufacturing of three-dimensional workpieces, along with a circulating air system.
[0029] Figure 3 This is an illustration of a first embodiment of an apparatus for additive manufacturing of three-dimensional workpieces according to the present invention;
[0030] Figure 4 This is an illustration of a second embodiment of an apparatus for additive manufacturing of three-dimensional workpieces according to the present invention, and...
[0031] Figure 5 is a cross-sectional view of the air intake mold. Detailed Implementation
[0032] Figure 1 illustrates an apparatus 1 for additive manufacturing of a three-dimensional workpiece 10, as known from the prior art. The apparatus 1 shown, also referred to as a 3D printer or printer, includes, for example, a heated build chamber 2, an adjustment device 5, a print head 3, and a receiving device 4 for receiving the three-dimensional workpiece 10. The adjustment device 5 includes an xy-axis system 15 with a print head receiving portion 25 arranged above the workpiece 10 for adjusting the print head 3 in the xy-plane, and a z-axis system 35 arranged below the workpiece for adjusting the receiving device 4 in the z-direction.
[0033] The adjustment device 5 ensures the three-dimensional fabrication of the workpiece on the receiving device 4, or so-called substrate, or base carrier, through the movement of its print head and receiving device. For this purpose, for example, a thermoplastic material is liquefied and applied layer by layer to the base carrier 4 to produce the workpiece 10 to be manufactured.
[0034] At the start of the printing process, the build chamber 2 is heated to the process temperature, for example by means of an integrated heating system (not shown). Printing takes place on a substrate 4, which is specially coated to improve the adhesion of the liquefied thermoplastic material to its surface. The substrate 4 is located on a pressure bed inside the build chamber 2. It can be held in position by vacuum or by locking bolts.
[0035] Figure 2 An apparatus 1 for additive manufacturing of a three-dimensional workpiece 10 is shown, together with a circulating air system 12, wherein the circulating air system 12 has a device 6 for temperature control and transport of gaseous fluid 7, an air inlet 40, and an air outlet 50. The air inlet 40 has a channel 41 connected to a build chamber 2 and an air inlet opening 43. A substrate carrier 4 is arranged in the build chamber 2, on which the workpiece 10 is placed. The substrate carrier 4 is arranged on a z-axis system 35. The gaseous fluid 7, or process air, is heated in the device 6 for temperature control and transport and is transported to the build chamber 2 via the channel 41 of the air inlet 40 through the air inlet opening 43 via a transport system (not shown) inside the device 6. The process air 7 flows into the build chamber 2, is evenly distributed there, and flows past the workpiece 10 during suction to the air outlet 50, which is immovably arranged on the bottom of the build chamber 2.
[0036] The disadvantage here is that the exhaust device 50 is fixedly placed at the bottom of the construction chamber 2. This makes it more difficult to selectively extract the process air 7 to generate optimal airflow at the workpiece 10.
[0037] Figure 3 A first embodiment of the device 1 according to the invention, or a printer for additive manufacturing of a three-dimensional workpiece 10, is shown, wherein the printer 1 has a build chamber 2; a print head 3; a receiving device 4, or substrate carrier, for receiving the three-dimensional workpiece 10; a circulating air system 12 for temperature control and transport of a gaseous fluid 7; and an adjustment device 5. The adjustment device 5 includes an xy-axis system 15 (not shown) with a print head receiving section 25 (not shown), and a z-axis system 35. The circulating air system 12 has a device 6 for temperature control and transport of the gaseous fluid 7, or process air; an air intake device 40 with four air intake openings 43 connected to the build chamber 2; and an exhaust device 50, wherein the exhaust device 50 is integrated into the z-axis system 35 and arranged to be adjustable by means of the z-axis system.
[0038] The exhaust device 50 has a gap 51 arranged in the housing 36 of the z-axis system 35.
[0039] The gap 51 of the exhaust device 50 is arranged below the receiving device 4 or the base carrier.
[0040] The air intake device 40 has a channel 41 with an air intake opening 43, through which gaseous fluid 7 can be delivered from the temperature control and delivery device 6 to the build chamber 2. A valve is arranged in the air intake opening 43 to regulate the input of process air 7.
[0041] The air intake opening 43 of the air intake device 40 is arranged above the workpiece 10 and the z-axis system 35.
[0042] The circulating air system 12 delivers gaseous fluid 7, or preferably process air (a protective gas), through the temperature control and transport device 6 via the channel 41 of the air inlet device 40 into the build chamber 2 via the air inlet opening 43 connected to the build chamber 2. The process air 7 flowing out of the air inlet opening 43 via a valve flows into the build chamber 2 and is evenly distributed within it. During extraction, the process air 7 flows over the workpiece 10 arranged on the substrate carrier 4 and reaches the gap 51 of the exhaust device 50. The circulating air system 12 ensures that the process air 7 flows in and out as needed, with the process air 7 being discharged from the build chamber 2 via the exhaust device 50. The temperature control of the build chamber 2 is optimized through the circulating air system 12.
[0043] The air intake opening 43 of the air intake device 40 is arranged above the workpiece 10.
[0044] The exhaust device 50 is integrated into the housing 36 of the z-axis system 35, which allows for adjustment of the exhaust device 50 at the z-height of the axis 35 and thus ensures the exhaust of process air 7 for the optimized circulating air system 12.
[0045] Due to this special arrangement of the components of the circulating air system, the temperature of the construction chamber 2 and the workpiece 10 is regulated to a constant.
[0046] The gap 51 of the exhaust device 50 is arranged in the housing 36 of the z-axis system 35 below the receiving device 4, ensuring that the airflow of the process air 7 is guided through the z-axis 35, or through the housing 36 of the z-axis 35, thereby regulating the temperature of the z-axis. The printer 1 also has only the central z-axis system 35.
[0047] The device 6 for temperature control and delivery of process air 7 is adjustable, thereby enabling the airflow and / or process air temperature to be adjusted according to the workpiece 10 and the required manufacturing process. The arrangement of the air inlet device 40 in conjunction with the arrangement of the exhaust device 50 ensures that the air inflow and outflow can be adjusted according to the workpiece 10.
[0048] Importantly, the process air 7 is centrally exhausted or centrally drawn below the construction chamber 2, thereby achieving a uniformly temperature-controlled airflow, which is simultaneously performed in the same assembly as the receiving device 4 or base carrier used for workpiece 10 for height adjustment. At the same time, the telescopic shaft of the z-axis 35 is temperature-controlled.
[0049] The circulating air system 12 forms a closed loop.
[0050] Figure 4 A second embodiment of the apparatus 1, or printer, according to the invention, for additive manufacturing of a three-dimensional workpiece 10 is shown, wherein the printer 1 has a build chamber 2; a print head 3; a receiving device 4, or substrate carrier, for receiving the three-dimensional workpiece 10; a circulating air system 12 for temperature control and transport of a gaseous fluid 7; and an adjustment device 5. The adjustment device 5 includes an xy-axis system 15 (not shown) with a print head receiving section 25 (not shown), and a z-axis system 35. The circulating air system 12 has a device 6 for temperature control and transport of the gaseous fluid 7, or process air; an air intake device 40 with three air intake openings 43 connected to the build chamber 2; and an exhaust device 50, wherein the exhaust device 50 is integrated into the z-axis system 35 and arranged to be adjustable by means of the z-axis system.
[0051] The exhaust device 50 has a gap 51 arranged in the housing 36 of the z-axis system 35.
[0052] The gap 51 of the exhaust device 50 is arranged below the receiving device 4 or the base carrier.
[0053] The air intake device 40 has a channel 41 and a connecting device 42 with an air intake opening 43, wherein the gaseous fluid 7 can be transported from the device 6 for temperature control and transport to the construction chamber 2 via the air intake device 40.
[0054] The air intake opening 43 of the air intake device 40 is arranged above the workpiece 10 and the z-axis system 35.
[0055] The circulating air system 12 delivers gaseous fluid 7, or preferably process air (a protective gas), through a temperature-regulating and conveying device 6 via a channel 41 (not shown) of the inlet device 40 to a connecting device 42 connected to the build chamber 2 via an inlet opening 43. The process air 7 flowing out of the inlet opening 43 flows into the build chamber 2 and is evenly distributed within it. During extraction, the process air 7 flows over the workpiece 10 arranged on the base carrier 4 and reaches the gap 51 of the exhaust device 50. The circulating air system 12 ensures the required inflow and outflow of process air 7, which is discharged from the build chamber 2 via the exhaust device 50. The temperature regulation of the build chamber 2 is optimized through the circulating air system 12.
[0056] The air inlet 43 of the connecting device 42 is arranged above the workpiece 10 and is staggered from each other by 90°.
[0057] The exhaust device 50 is integrated into the housing 36 of the z-axis system 35, which allows for adjustment of the exhaust device 50 at the z-height of the axis system 35 and thus ensures the exhaust of process air 7 for the optimized circulating air system 12.
[0058] Due to this special arrangement of the components of the circulating air system, the temperature of the construction chamber 2 and the workpiece 10 is regulated to a constant.
[0059] The gap 51 of the exhaust device 50 is arranged in the housing 36 of the z-axis system 36 below the receiving device 4, ensuring that the airflow of the process air 7 is guided through the z-axis system 35, or through the housing 36 of the z-axis system 35, thereby also regulating the temperature of the z-axis. The printer 1 also has only the central z-axis system 35.
[0060] The device 6 for temperature control and delivery of process air 7 is adjustable, thereby enabling the airflow and / or process air temperature to be adjusted according to the workpiece 10 and the required manufacturing process. The arrangement of the connection device 42 of the air inlet device 40 in conjunction with the arrangement of the exhaust device 50 ensures that the air inflow and outflow can be adjusted according to the workpiece 10.
[0061] Importantly, the process air 7 is centrally exhausted or centrally drawn below the construction chamber 2, thereby achieving a uniformly temperature-controlled airflow, which is simultaneously performed in the same assembly as the receiving device 4 or base carrier used for workpiece 10 for height adjustment. At the same time, the telescopic shaft of the z-axis 35 is temperature-controlled.
[0062] The circulating air system 12 in this embodiment also forms a closed loop.
[0063] The air intake opening 43 of the air intake device 40 is adapted to accommodate a replaceable air intake mold 44, wherein the air intake mold 44 has a different geometry, or opening geometry, depending on the workpiece geometry of the workpiece 10. In this embodiment, the air intake opening 43 has a rectangular opening geometry.
[0064] The opening geometry of the air intake mold 44 can be adjusted according to the component size, thereby achieving optimal temperature control of the build chamber 2. The shape of the air intake mold 44, or the air inlet and exhaust port, can be varied (see Figure 5). Therefore, the air intake mold 44 can have different air slot shapes.
[0065] Figure 5 shows various cross-sectional views of the intake mold 44 of the intake opening 43 of the intake device 40. The intake mold 44 can be varied and consists, for example, of a long, rounded slit 45 (5c) or a plurality of small holes 46 (5d).
[0066] For example, when choosing a geometry, the results of the corresponding flow simulation are important, which enables the selection of the optimal shape.
[0067] As an alternative to the one-piece design of the air intake molds 44, 45, and 46, multiple air intakes 47 can be placed in a single air intake mold 44. Figure 5e ).
Claims
1. An apparatus (1) for additive manufacturing of a three-dimensional workpiece (10), the apparatus comprising a build chamber (2), at least one print head (3), a receiving device (4) for receiving the three-dimensional workpiece (10), a circulating air system (12) for temperature control and transport of a gaseous fluid (7), and an adjustment device (5) comprising an xy-axis system (15) and a z-axis system (35), the xy-axis system having a print head receiving section (25), characterized in that, The circulating air system (12) has a device (6) for temperature regulation and transport of gaseous fluid (7), an air intake device (40) with at least two air intake openings (43) connected to the construction chamber (2), and an exhaust device (50), wherein the exhaust device (50) is integrated in the z-axis system (35) and arranged to be adjustable by means of the z-axis system, the z-axis system (35) is arranged below the receiving device (4) and has a telescopic shaft, wherein the exhaust device (50) has a gap (51) arranged in the housing (36) of the z-axis system (35), wherein the gaseous fluid (7) flows through the three-dimensional workpiece (10) arranged on the receiving device (4) and reaches the gap (51) of the exhaust device (50) when extracted, thereby guiding the gaseous fluid (7) through the z-axis system (35) and regulating the temperature of the z-axis system (35).
2. The apparatus (1) according to claim 1. Its features are, The gap (51) of the exhaust device (50) is arranged below the receiving device (4).
3. The apparatus (1) according to claim 1 or 2. Its features are, The air intake device (40) has a channel (41) and a connecting device (42) with an air intake opening (43), wherein the gaseous fluid (7) is delivered from the device (6) for temperature regulation and delivery to the construction chamber (2) via the air intake device (40).
4. The apparatus (1) according to any one of claims 1 or 3. Its features are, The air intake opening (43) of the air intake device (40) is arranged above the workpiece (10) and the z-axis system (35).
5. The apparatus (1) according to any one of the preceding claims. Its features are, The air intake opening (43) of the air intake device (40) is adapted to receive a replaceable air intake mold (44).
6. The apparatus (1) according to claim 5. Its features are, The air intake mold (44) has a different geometry.
7. The apparatus (1) according to any one of claims 1 to 4. Its features are, The air intake opening (43) of the air intake device (40) includes a valve.
8. A method for additive manufacturing of a three-dimensional workpiece (10), which utilizes the apparatus (1) according to any one of the preceding claims.