Device for rapidly heating and cooling 3D grafting printing powder bed and parts
By designing a sandwich structure for the heating and cooling pipes in the 3D grafting printing equipment, the problems of insufficient heating and long cooling time were solved, achieving rapid and uniform heating and cooling, and improving printing efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHINA WEAPON SCI ACADEMY NINGBO BRANCH
- Filing Date
- 2025-04-09
- Publication Date
- 2026-04-21
AI Technical Summary
Existing 3D grafting printing equipment does not heat the metal powder and grafting parts sufficiently, and the cooling time after printing is long, resulting in low overall production efficiency.
Design a device comprising a powder bed forming cylinder and a substrate connecting base, both having a sandwich structure, with built-in heating and cooling pipes, heating and cooling controlled by a temperature control system to ensure uniform temperature distribution, and rapid part removal achieved by a lifting mechanism.
It enables rapid and uniform heating of metal powder and grafting components, reduces printing defects, shortens cooling time, and improves overall printing efficiency.
Smart Images
Figure CN224143500U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of additive manufacturing technology and relates to a device for rapid heating and cooling of powder bed and parts in 3D grafting printing. Background Technology
[0002] 3D grafting printing is an innovative additive manufacturing method that combines 3D printing and grafting technologies. By grafting different materials layer by layer during the printing process, it forms complex and multifunctional structures, integrating the advantages of traditional processing methods with 3D printing. It is particularly suitable for manufacturing large and complex structural products. Using this technology, the external structure of the product is manufactured through traditional processing methods such as cutting and casting to ensure strength and performance stability, while the complex internal structure is achieved through 3D printing for rapid and precise manufacturing. 3D grafting printing technology is widely used in the biomedical field (such as personalized medical devices and artificial organ printing), electronic devices (such as flexible electronics and sensors), and aerospace (such as lightweight structural components). Its main advantages include high customization, material integration, and efficient production. With continuous technological advancements, 3D grafting printing technology is showing enormous development potential in even more fields.
[0003] 3D grafting printing is an innovative method combining traditional processing and additive manufacturing technologies. First, the grafting substrate is fixed to a substrate connecting base and leveled to provide a stable platform for subsequent operations. Then, the part to be grafted is precisely fixed onto the substrate, and its position is adjusted so that its upper surface coincides with the focal plane of the 3D printing heat source to ensure printing accuracy. Next, the powder bed forming cylinder is filled with the same or different types of metal powder, and the powder spreading system of the 3D printing equipment is used to smooth the metal powder, forming a uniform powder layer. Simultaneously, the metal powder and the grafting part are preheated to optimize their physical state. After completing the above preparations, the 3D printing equipment is started to melt the metal powder layer by layer according to a predetermined program to form the desired structure. Finally, after the metal powder cools to room temperature, the printed part is removed, thus achieving the efficient manufacturing of complex structural components.
[0004] Preheating the metal powder and grafting parts is a crucial step in 3D grafting printing. Preheating not only reduces thermal stress and prevents cracking, but also promotes powder melting, reduces printing defects, and improves print quality. However, because the metal powder and grafting parts are typically located deep within the powder bed forming cylinder, and existing 3D grafting printing equipment on the market only provides bottom heating, the heating effect on the metal powder and grafting parts is insufficient, resulting in low efficiency. Furthermore, after 3D grafting printing, a long cooling time is required before the printed parts can be removed from the equipment, further reducing overall production efficiency.
[0005] To address the aforementioned issues, a device specifically designed for rapid heating and cooling of the powder bed and parts in 3D grafting printing needs to be developed to improve overall printing efficiency. Summary of the Invention
[0006] The technical problem to be solved by this utility model is to provide a device for rapid heating and cooling of powder bed and parts in 3D grafting printing. It has the characteristics of simple and reasonable structure and low cost, which can speed up the part removal speed and improve the overall printing efficiency.
[0007] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows: a device for rapid heating and cooling of 3D grafting printing powder bed and parts, characterized in that: it includes a powder bed forming cylinder, a substrate connecting base and a lifting mechanism. The substrate connecting base is movably set in the powder bed forming cylinder through the lifting mechanism. The bottom of the substrate connecting base is provided with a connecting plate that extends out of the bottom of the powder bed forming cylinder and connects to the lifting mechanism. Both the powder bed forming cylinder and the substrate connecting base have a sandwich structure. Heating pipes and cooling pipes are respectively installed in the sandwich. Multiple temperature sensors are distributed on the powder bed forming cylinder and the substrate connecting base.
[0008] As an improvement, the powder bed forming cylinder is a square cylinder assembled from a base plate, an integral outer plate, or four outer plates and four inner plates. The integral outer plate or the four outer plates are vertically installed on the left, right, front, and rear edges of the base plate, respectively. The four inner plates are vertically installed on the base plate inside the outer plates. There is a certain gap between the outer plates and the inner plates to form a hollow interlayer. The first heating pipe and the first cooling pipe are installed in the hollow interlayer.
[0009] Furthermore, the substrate connecting base includes a substrate connecting plate and a substrate connecting base cover plate. The substrate connecting plate is a square plate corresponding to the inner cavity of the powder bed forming cylinder. A connecting plate is provided at the bottom center of the substrate connecting plate, passing through the bottom plate and connecting to the lifting mechanism. The substrate connecting base cover plate is fixed below the substrate connecting plate by screws. A U-shaped sandwich is formed between the substrate connecting base cover plate and the substrate connecting plate. The second heating pipe and the second cooling pipe are installed in the sandwich.
[0010] Furthermore, the first heating tube, the second heating tube, the first cooling tube, and the second cooling tube are all conformal designs, with shapes including but not limited to spiral, U-shaped, slotted, circular, U-shaped, or W-shaped. The cross-sections of the first heating tube, the second heating tube, the first cooling tube, and the second cooling tube are including but not limited to circular, rectangular, elliptical, flat, or irregular shapes. The interior of the first heating tube and the second heating tube is a heating wire structure, and the interior of the first cooling tube and the second cooling tube is filled with a cooling medium. The first heating tube, the second heating tube, the first cooling tube, and the second cooling tube are connected to an external temperature control system, which controls the heating and cooling.
[0011] Furthermore, the first heating pipe and the first cooling pipe are designed in a spiral shape and are wound inside the interlayer of the powder bed forming cylinder. The first cooling pipe is arranged in parallel with the first heating pipe. The second heating pipe and the second cooling pipe adopt a U-shaped design with a circular cross-section. The second cooling pipe is arranged in parallel with the second heating pipe. The distance between the first cooling pipe and the first heating pipe, and between the second cooling pipe and the second heating pipe, is 10 to 100 mm. The cooling medium inside the first cooling pipe and the second cooling pipe is water, ethylene glycol, or glycerol.
[0012] Furthermore, the first heating tube and the first cooling tube are connected as a whole by a fixing component and fixed in the interlayer of the powder bed forming cylinder by screws; the second heating tube and the second cooling tube are fixed as a whole by a fixing component and fixed in the interlayer of the substrate connecting base by screws, and the fixing component is a clamp.
[0013] Furthermore, the temperature sensor includes multiple detection units distributed on the powder bed forming body and the substrate connecting base, specifically: a first temperature sensor installed on the left side of the powder bed forming cylinder to detect the temperature on the left side of the powder bed forming cylinder; a second temperature sensor installed on the right side of the powder bed forming cylinder to detect the temperature on the right side of the powder bed forming cylinder; a third temperature sensor installed on the front of the powder bed forming cylinder to detect the temperature on the front side of the powder bed forming cylinder; a fourth temperature sensor installed on the rear side of the powder bed forming cylinder to detect the temperature on the rear side of the powder bed forming cylinder; a fifth temperature sensor installed on the left side of the substrate connecting base to detect the temperature on the left side of the substrate connecting base; a sixth temperature sensor installed on the right side of the substrate connecting base to detect the temperature on the right side of the substrate connecting base; a seventh temperature sensor installed on the front of the substrate connecting base to detect the temperature on the front of the substrate connecting base; and an eighth temperature sensor installed on the rear of the substrate connecting base to detect the temperature on the rear of the substrate connecting base.
[0014] Furthermore, a fixed frame is provided at the bottom of the powder bed forming cylinder, and a lifting mechanism is installed on the fixed frame. The lifting mechanism includes a servo motor, a slider, an integrated base and guide rail, and an encoder. The slider is slidably installed on the guide rail and connected to the connecting plate of the substrate connecting base. A first limit sensor, a second limit sensor, and a third limit sensor are provided on the guide rail to limit the lower limit position, zero point position, and upper limit position of the lifting mechanism.
[0015] Furthermore, the fixing frame is an L-shape with the upper end folded over. The upper end of the fixing frame is tightly fixed to the bottom of the base plate of the powder bed forming cylinder by screws. The vertical surface of the fixing frame has mounting holes, and the lifting mechanism is fixed to the fixing frame by screws.
[0016] Finally, the shape of the powder bed forming cylinder is not limited to square; it can also be rectangular or circular.
[0017] Compared with existing technologies, the advantages of this invention are as follows: The structural design of the heating and cooling system is optimized. Both the powder bed forming cylinder and the substrate connecting base have a sandwich structure. Heating pipes and cooling pipes are installed within the sandwich, and the paths of the first heating pipe and the first cooling pipe, and the second heating pipe and the second cooling pipe are arranged parallel to each other, ensuring a consistent distance between the heat source and the cooling area, thus achieving a more uniform temperature distribution. The heating pipes use a heating wire structure, and the cooling pipes are filled with a high-efficiency cooling medium, achieving high efficiency in both preheating and cooling processes. The heating pipes and cooling pipes are fixed as a whole within the sandwich of the powder bed forming cylinder and the substrate connecting base using fixing components, effectively preventing displacement or loosening of the pipes during operation and improving system stability. The fixing components use clamps, making full use of the sandwich space, achieving a compact spatial layout, saving equipment volume, and facilitating later maintenance and replacement.
[0018] This invention features a simple and reasonable structure with low cost. It can rapidly and uniformly heat the metal powder and grafting parts during the 3D grafting printing process, ensuring effective control of thermal stress during printing and preventing parts from cracking. At the same time, it promotes powder melting and reduces printing defects. In addition, after printing, the device significantly shortens the cooling time of the metal powder and parts through an efficient cooling system, thereby speeding up the part removal process and improving the overall printing efficiency. It is suitable for large-scale promotion and application. Attached Figure Description
[0019] Figure 1 This is a partial cross-sectional view of an embodiment of the present utility model;
[0020] Figure 2 This is a perspective view of an embodiment of the present utility model;
[0021] Figure 3 This is a half-sectional view of an embodiment of the present utility model;
[0022] Figure 4 This is another partial cross-sectional view of an embodiment of the present utility model.
[0023] Explanation of reference numerals in the attached drawings: 1. Powder bed forming cylinder; 11. Outer plate; 12. Base plate; 13. Inner plate; 2. Base plate connecting base; 21. Base plate connecting plate; 22. Base plate connecting base cover plate; 3. Lifting mechanism; 31. Servo motor; 32. Slider; 33. Integrated base and guide rail; 34. Encoder; 35. First limit sensor; 36. Second limit sensor; 37. Third limit sensor; 4. Fixing frame; 51. First heating tube; 52. Second heating tube; 61. First cooling tube; 62. Second cooling tube; 71. First temperature sensor; 72. Second temperature sensor; 73. Third temperature sensor; 74. Fourth temperature sensor; 75. Fifth temperature sensor; 76. Sixth temperature sensor; 77. Seventh temperature sensor; 78. Eighth temperature sensor. Detailed Implementation
[0024] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.
[0025] like Figures 1-4 As shown, a device for rapid heating and cooling of a 3D grafted printing powder bed and parts includes a powder bed forming cylinder 1, a substrate connecting base 2, a lifting mechanism 3, and a fixing frame 4. The substrate connecting base 2 is movably mounted inside the powder bed forming cylinder 1 via the lifting mechanism 3. A connecting plate 210 is provided at the bottom of the substrate connecting base 2, extending out of the bottom of the powder bed forming cylinder 1 and connecting to the lifting mechanism 3. Both the powder bed forming cylinder 1 and the substrate connecting base 2 have a sandwich structure, in which heating pipes and cooling pipes are respectively installed. Multiple temperature sensors are distributed on the powder bed forming cylinder 1 and the substrate connecting base 2.
[0026] The specific structure is as follows: The powder bed forming cylinder 1 is a square cylinder assembled from a base plate 12, an integral outer plate 11 and four inner plates 13. The integral outer plate 11 is vertically installed on the left, right and front and rear edges of the base plate 12. The four inner plates 13 are vertically installed on the base plate 12 and located inside the outer plate 11. There is a certain gap between the outer plate 11 and the inner plate 13 to form a hollow sandwich layer 10. Of course, four outer plates 11 can be used instead of the integral outer plate 11, and the effect is similar. The first heating pipe 51 and the first cooling pipe 61 are installed in the hollow sandwich layer 10. The substrate connecting base 2 includes a substrate connecting plate 21 and a substrate connecting base cover plate 22. The substrate connecting plate 21 is a square plate corresponding to the inner cavity of the powder bed forming cylinder 1. A connecting plate 210 is provided at the bottom center of the substrate connecting plate 21, which passes through the bottom plate 12 and is connected to the lifting mechanism 3. The substrate connecting base cover plate 22 is fixed to the bottom of the substrate connecting plate 21 by screws. A U-shaped sandwich layer 20 is formed between the substrate connecting base cover plate 22 and the substrate connecting plate 21. The second heating pipe 52 and the second cooling pipe 62 are installed in the sandwich layer 20.
[0027] The first heating element 51, the second heating element 52, the first cooling element 61, and the second cooling element 62 are all conformal designs, with shapes including but not limited to spiral, U-shape, slotted, circular, circular, or W-shaped. The cross-sections of the first heating element 51, the second heating element 52, the first cooling element 61, and the second cooling element 62 include, but are not limited to, circular, rectangular, elliptical, flat, and irregular shapes. The interior of the first heating element 51 and the second heating element 52 is a heating wire structure, and the interior of the first cooling element 61 and the second cooling element 62 is filled with a cooling medium, such as water, ethylene glycol solution, or propylene glycol solution. The first heating element 51, the second heating element 52, the first cooling element 61, and the second cooling element 62 are connected to an external temperature control system, which controls the heating and cooling.
[0028] In this embodiment, the first heating pipe 51 and the first cooling pipe 61 are designed in a spiral shape and are wound inside the hollow interlayer 10 of the powder bed forming cylinder 1. The first cooling pipe 61 is arranged parallel to the first heating pipe 51, with a distance of 50mm between them. The second heating pipe 52 and the second cooling pipe 62 adopt a U-shaped design with a circular cross-section. The second cooling pipe 62 is arranged parallel to the second heating pipe 52, with a distance of 40mm between them. The internal cooling medium of the first cooling pipe 61 and the second cooling pipe 62 is water. The parallel arrangement of the first cooling pipe 61 and the first heating pipe 51, and the second cooling pipe 62 and the second heating pipe 52, ensures that the distance between the heat source and the cooling area is consistent, achieving a uniform temperature distribution.
[0029] During installation, the first heating pipe 51 and the first cooling pipe 61 are connected as a whole by a fixing component and fixed to the hollow interlayer 10 of the powder bed forming cylinder 1 with screws; the second heating pipe 52 and the second cooling pipe 62 are fixed as a whole by a fixing component and fixed to the interlayer 20 of the substrate connecting base 2 with screws. The fixing component effectively prevents displacement or loosening of the pipelines during operation, improves system stability, and optimizes the spatial layout. In this embodiment, the fixing component uses a clamp, which facilitates installation, positioning, and disassembly, and makes it easy to maintain and replace later.
[0030] The temperature sensor includes multiple detection units distributed on the powder bed forming cylinder 1 and the substrate connecting base 2, specifically: a first temperature sensor 71, installed on the left side of the powder bed forming cylinder 1, for detecting the temperature on the left side of the powder bed forming cylinder 1; a second temperature sensor 72, installed on the right side of the powder bed forming cylinder 1, for detecting the temperature on the right side of the powder bed forming cylinder 1; a third temperature sensor 73, installed on the front of the powder bed forming cylinder 1, for detecting the temperature on the front side of the powder bed forming cylinder 1; a fourth temperature sensor 74, installed on the rear side of the powder bed forming cylinder 1, for detecting the temperature on the rear side of the powder bed forming cylinder 1; a fifth temperature sensor 75, installed on the left side of the substrate connecting base 2, for detecting the temperature on the left side of the substrate connecting base 2; a sixth temperature sensor 76, installed on the right side of the substrate connecting base 2, for detecting the temperature on the right side of the substrate connecting base 2; a seventh temperature sensor 77, installed on the front of the substrate connecting base 2, for detecting the temperature on the front of the substrate connecting base 2; and an eighth temperature sensor 78, installed on the rear of the substrate connecting base 2, for detecting the temperature on the rear of the substrate connecting base 2.
[0031] A fixed frame 4 is provided at the bottom of the powder bed forming cylinder 1. The lifting mechanism 3 is installed on the fixed frame 4. The lifting mechanism includes a servo motor 31, a slider 32, an integrated base and guide rail 33, and an encoder 34. The slider 32 is slidably installed on the integrated base and guide rail 33 and connected to the connecting plate 210 of the substrate connecting base 2. The integrated base and guide rail 33 are provided with a first limit sensor 35, a second limit sensor 36, and a third limit sensor 37. The first limit sensor 35 is the lower limit position of the lifting mechanism 3, the second limit sensor 36 is the zero point position of the lifting mechanism 3, and the third limit sensor 37 is the upper limit position of the lifting mechanism. In this way, the entire lifting mechanism 3 is connected to the substrate connecting base 2 and provides up and down movement function.
[0032] The fixing frame 4 is an L-shaped structure with the upper end folded over. The upper end of the fixing frame 4 is fixed to the bottom of the base plate 12 of the powder bed forming cylinder 1 by screws. The vertical surface of the fixing frame 4 has mounting holes. The lifting mechanism 3 is fixed to the fixing frame 4 by screws.
[0033] The shape of the powder bed forming cylinder 1 is not limited to square; it can also be rectangular or circular.
[0034] Specific workflow and usage process:
[0035] In 3D grafting printing, the grafting substrate is first placed on the substrate connecting base 2. The lifting mechanism 3 is activated to raise the grafting substrate to a suitable position, and a leveling tool is used for leveling. The part to be grafted is placed on the grafting substrate and fixed. The lifting mechanism 3 is activated to lower the upper surface of the grafting part until it coincides with the focal plane of the 3D printing heat source. Metal powder of the same or different material is filled into the powder bed forming cylinder 1. The 3D printing powder spreading system is used to smooth the metal powder, forming a uniform powder layer. The temperature control system is activated, and the temperature sensor monitors the device temperature in real time. The first heating tube 51 and the second heating tube 52 heat synchronously to fully preheat the metal powder and the grafting part. Heating is stopped after the temperature reaches the set parameters, and the 3D printing equipment is started to melt the metal powder layer by layer according to the predetermined program to form the desired structure. After printing is completed, the temperature control system is activated, and the first cooling tube 61 and the second cooling tube 62 cool synchronously. Cooling is stopped after the temperature reaches the set parameters. Finally, after the metal powder cools to room temperature, the printed part is removed, thus achieving efficient manufacturing of complex structural parts.
[0036] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A device for rapid heating and cooling of 3D grafting print beds and parts, characterized by: The device includes a powder bed forming cylinder, a substrate connecting base, and a lifting mechanism. The substrate connecting base is vertically mounted inside the powder bed forming cylinder via the lifting mechanism. A connecting plate extends from the bottom of the substrate connecting base through the bottom of the powder bed forming cylinder and connects to the lifting mechanism. Both the powder bed forming cylinder and the substrate connecting base have a sandwich structure, in which heating pipes and cooling pipes are installed respectively. Multiple temperature sensors are distributed on both the powder bed forming cylinder and the substrate connecting base.
2. The apparatus of claim 1, wherein: The powder bed forming cylinder is a square cylinder assembled from a base plate, an integral outer plate or four outer plates and four inner plates. The integral outer plate or four outer plates are respectively vertically installed on the left, right, front and back edges of the base plate. The four inner plates are vertically installed on the base plate inside the outer plates. There is a certain gap between the outer plates and the inner plates to form a hollow sandwich layer. The first heating pipe and the first cooling pipe are installed in the hollow sandwich layer.
3. The apparatus of claim 2, wherein: The substrate connecting base includes a substrate connecting plate and a substrate connecting base cover plate. The substrate connecting plate is a square plate corresponding to the inner cavity of the powder bed forming cylinder. A connecting plate is provided at the bottom center of the substrate connecting plate, passing through the bottom plate and connecting to the lifting mechanism. The substrate connecting base cover plate is fixed below the substrate connecting plate by screws. A U-shaped sandwich is formed between the substrate connecting base cover plate and the substrate connecting plate. The second heating pipe and the second cooling pipe are installed in the sandwich.
4. The apparatus of claim 3, wherein: The first heating tube, the second heating tube, the first cooling tube, and the second cooling tube are all conformal designs, and their shapes include, but are not limited to, spiral, U-shaped, slotted, circular, U-shaped, or W-shaped. The cross-sections of the first heating tube, the second heating tube, the first cooling tube, and the second cooling tube include, but are not limited to, circular, rectangular, elliptical, or flat shapes. The interior of the first heating tube and the second heating tube is a heating wire structure, and the interior of the first cooling tube and the second cooling tube is filled with a cooling medium. The first heating tube, the second heating tube, the first cooling tube, and the second cooling tube are connected to an external temperature control system, which controls the heating and cooling.
5. The apparatus of claim 4, wherein: The first heating pipe and the first cooling pipe are designed in a spiral shape and are wound inside the interlayer of the powder bed forming cylinder. The first cooling pipe is arranged in parallel with the first heating pipe. The second heating pipe and the second cooling pipe adopt a U-shaped design with a circular cross-section. The second cooling pipe is arranged in parallel with the second heating pipe. The distance between the first cooling pipe and the first heating pipe, and between the second cooling pipe and the second heating pipe, is 10 to 100 mm. The cooling medium inside the first cooling pipe and the second cooling pipe is water, ethylene glycol or glycerol.
6. The apparatus of claim 5, wherein: The first heating tube and the first cooling tube are connected as a whole by a fixing component and fixed in the interlayer of the powder bed forming cylinder by screws; the second heating tube and the second cooling tube are fixed as a whole by a fixing component and fixed in the interlayer of the substrate connecting base by screws, and the fixing component is a clamp.
7. The apparatus of claim 1, wherein: The temperature sensor includes multiple detection units distributed on the powder bed forming body and the substrate connecting base, specifically: a first temperature sensor installed on the left side of the powder bed forming cylinder to detect the temperature on the left side of the powder bed forming cylinder; a second temperature sensor installed on the right side of the powder bed forming cylinder to detect the temperature on the right side of the powder bed forming cylinder; a third temperature sensor installed at the front of the powder bed forming cylinder to detect the temperature at the front of the powder bed forming cylinder; a fourth temperature sensor installed at the rear of the powder bed forming cylinder to detect the temperature at the rear of the powder bed forming cylinder; a fifth temperature sensor installed on the left side of the substrate connecting base to detect the temperature at the left side of the substrate connecting base; a sixth temperature sensor installed on the right side of the substrate connecting base to detect the temperature at the right side of the substrate connecting base; a seventh temperature sensor installed at the front of the substrate connecting base to detect the temperature at the front of the substrate connecting base; and an eighth temperature sensor installed at the rear of the substrate connecting base to detect the temperature at the rear of the substrate connecting base.
8. The apparatus of any one of claims 1 to 7, wherein: The bottom of the powder bed forming cylinder is provided with a fixed frame, and the lifting mechanism is installed on the fixed frame. The lifting mechanism includes a servo motor, a slider, an integrated base and guide rail, and an encoder. The slider is installed on the guide rail and connected to the connecting plate of the substrate connecting base. The guide rail is provided with a first limit sensor, a second limit sensor, and a third limit sensor to limit the lower limit position, zero point position, and upper limit position of the lifting mechanism.
9. The apparatus of claim 8, wherein: The fixing frame is an L-shape with the upper end folded over. The upper end of the fixing frame is fixed to the bottom of the base plate of the powder bed forming cylinder by screws. The vertical surface of the fixing frame has mounting holes, and the lifting mechanism is fixed to the fixing frame by screws.
10. The apparatus of any one of claims 1 to 7, wherein: The shape of the powder bed forming cylinder is not limited to square; it can also be rectangular or circular.