Additive manufacturing forming device

Abstract

The utility model belongs to the field of additive manufacturing, and relates to an additive manufacturing forming device which comprises a heat preservation forming cylinder, a Z-axis lifting device and a powder bed. The Z-axis lifting device is arranged in the heat preservation forming cylinder in the axial direction of the heat preservation forming cylinder and freely ascends and descends in the heat preservation forming cylinder. The powder bed is arranged on the Z-axis lifting device in the radial direction of the heat preservation forming cylinder and synchronously moves along with the Z-axis lifting device. According to the additive manufacturing forming device, the forming difficulty can be reduced, and the forming quality can be improved.

Description

Technical Field

[0001] The utility model belongs to the field of additive manufacturing, and relates to an additive manufacturing forming device, in particular to an additive manufacturing forming device capable of preheating and keeping the additive medium warm. Background Art

[0002] In metal additive manufacturing, the sintering process of titanium alloy, aluminum alloy and other high-temperature metal powders is prone to thermal stress and thermal deformation due to the large temperature gradient in various parts of the parts, which in turn causes problems such as difficulty in forming the parts and poor forming shape accuracy. In addition, the particle melting process in the titanium aluminum alloy additive SLM technology developed in the new material field is not ideal, while the particle melting of titanium aluminum alloy powders formed at high temperatures has improved. Therefore, based on the above content, there is an urgent need for a device that can preheat the additive manufacturing medium, especially the metal powder, while keeping the printing area constant at a certain temperature. Utility Model Content

[0003] In order to solve the above-mentioned technical problems existing in the background technology, the utility model provides an additive manufacturing forming device which can reduce the forming difficulty and improve the forming quality.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] An additive manufacturing forming device, characterized in that: the additive manufacturing forming device includes a heat-insulating forming cylinder, a Z-axis lifting device and a powder bed; the Z-axis lifting device is placed inside the heat-insulating forming cylinder along the axial direction of the heat-insulating forming cylinder and can be freely lifted and lowered in the heat-insulating forming cylinder; the powder bed is arranged on the Z-axis lifting device along the radial direction of the heat-insulating forming cylinder and moves synchronously with the Z-axis lifting device.

[0006] The above-mentioned heat preservation forming cylinder includes an inner cylinder, an intermediate cylinder and an outer cylinder; the inner cylinder, the intermediate cylinder and the outer cylinder are coaxially mounted in sequence from the inside to the outside; the Z-axis lifting device is placed inside the inner cylinder along the axial direction of the inner cylinder and can be lifted and lowered freely in the inner cylinder; a vacuum layer is formed between the inner cylinder and the intermediate cylinder.

[0007] A reflective heat-insulating layer is arranged on the inner wall of the intermediate tube.

[0008] An air flow channel or a water cooling flow channel is arranged between the intermediate tube and the outer tube, and an opening communicating with the air flow channel or a flow channel joint communicating with the water cooling flow channel is arranged on the tube wall of the outer tube.

[0009] The two ends of the thermal insulation forming cylinder are provided with annular heat insulation plates; the annular heat insulation plates cover the inner cylinder end, the middle cylinder end and the outer cylinder end; and a thermal insulation sealing module is provided between the outer cylinder end and the annular heat insulation plates.

[0010] The above-mentioned additive manufacturing forming device also includes a preheating forming platform; the preheating forming platform is arranged on a Z-axis lifting device along the radial direction of the heat-insulating forming cylinder and moves synchronously with the Z-axis lifting device; the powder bed is arranged on the preheating forming platform.

[0011] The above-mentioned preheating forming platform includes a heating module and a cooling module arranged in sequence from top to bottom; the cooling module is fixedly arranged on the Z-axis lifting device through the heating sealing module and moves synchronously with the Z-axis lifting device; the powder bed includes a powder bed bottom plate; the heating module heats the medium used for additive on the powder bed bottom plate.

[0012] The preheating forming platform also includes a temperature sensor and a current on-off device; the temperature sensor is placed inside the heating module; the current on-off device is placed outside the heating module and is connected to the temperature sensor via a wire.

[0013] The preheating forming platform further comprises a heat insulation module arranged between the heating module and the cooling module.

[0014] The heating module is one or more of a resistance wire heating component, a coil heating component or a laser heating component; the cooling module is one or more of a water cooling structure, an air cooling structure or a semiconductor refrigeration cooling structure.

[0015] The advantages of the utility model are:

[0016] The utility model provides an additive manufacturing forming device, including a heat-insulating forming cylinder, a Z-axis lifting device and a powder bed; the Z-axis lifting device is placed inside the heat-insulating forming cylinder along the axial direction of the heat-insulating forming cylinder and can be lifted and lowered freely in the heat-insulating forming cylinder; the powder bed is arranged on the Z-axis lifting device along the radial direction of the heat-insulating forming cylinder and moves synchronously with the Z-axis lifting device. The utility model solves the problem of large thermal stress and thermal deformation caused by large temperature gradients of powder beds at different heights during part forming, reduces the forming difficulty, and improves the forming quality. The utility model achieves heat insulation of powder in the forming cylinder through measures such as a heat-insulating forming cylinder (heat-insulating layer, vacuum layer, reflective layer, external heat-insulating), reduces the temperature gradients at different heights, isolates the high-temperature forming cylinder from the equipment, reduces the influence of the high-temperature forming area on the other parts of the equipment, and improves the reliability of the equipment. In addition, the utility model can directly increase the temperature of the powder, and through the heat-insulating vacuum insulation layer, it can not only ensure the temperature consistency of powders at different depths in the powder bed, but also isolate the equipment from the high-temperature powder bed, ensure that the temperature of other parts except the powder is consistent with that of conventional equipment, improve the working life of other parts in the equipment, and further increase the reliability of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the material manufacturing and forming device provided by the utility model;

[0018] Figure 2 It is a structural schematic diagram of the preheating forming platform adopted by the utility model;

[0019] Figure 3 It is a structural schematic diagram of the heating module (single-layer resistance wire) adopted by the utility model;

[0020] Figure 4 It is a schematic diagram of the structure of the heating module (multi-layer resistance wire) adopted by the utility model;

[0021] Figure 5 It is a schematic diagram of the structure of the heating module (coil) adopted by the utility model;

[0022] Figure 6 It is a structural schematic diagram of the heating module (laser heating) adopted by the utility model;

[0023] Figure 7 It is a structural schematic diagram of the cooling module adopted by the utility model;

[0024] Figure 8 It is a structural schematic diagram of the heat preservation forming cylinder adopted in the utility model;

[0025] in:

[0026] 1-insulation forming cylinder; 11-inner cylinder; 12-vacuum layer; 13-reflective insulation layer; 14-water-cooling flow channel; 15-outer cylinder; 16-flow channel joint; 17-insulation sealing module; 18-insulation board; 2-preheating forming platform; 21-heating module; 211-high frequency coil; 212-laser light source; 213-collimation module; 214-reflection module; 215-homogenization module; 216-focusing module; 217-aperture module; 218-temperature sensor; 219-current on-off device; 22-insulation module; 23-cooling module; 24-heating and sealing module; 3-Z-axis lifting device; 4-powder bed; 41-powder bed bottom plate. DETAILED DESCRIPTION

[0027] See also Figure 1The utility model provides an additive manufacturing forming device, including a heat-insulating forming cylinder 1, a Z-axis lifting device 3 and a powder bed 4; the Z-axis lifting device 3 is placed inside the heat-insulating forming cylinder 1 along the axial direction of the heat-insulating forming cylinder 1 and can be lifted and lowered freely in the heat-insulating forming cylinder 1; the powder bed 4 is arranged on the Z-axis lifting device 3 along the radial direction of the heat-insulating forming cylinder 1 and moves synchronously with the Z-axis lifting device 3. The powder bed 4 is a powder bearing area. As the preheating forming platform is lowered, the powder thickness gradually increases. The function of the heat-insulating forming cylinder 1 is mainly to ensure that the temperature of powders at different heights in the powder bed is consistent, and to ensure that heat cannot be dissipated to affect other parts of the equipment. The Z-axis lifting device 3 is consistent with the other SLM equipment. Through a linear motion mechanism, such as a lead screw and a linear guide mechanism, it provides power to the forming platform so that it can move up and down.

[0028] See also Figure 2 The additive manufacturing forming device provided by the utility model also includes a preheating forming platform 2, which has heating, heat insulation, water cooling and sealing functions. The preheating forming platform 2 is arranged on the Z-axis lifting device 3 along the radial direction of the heat-insulating forming cylinder 1 and moves synchronously with the Z-axis lifting device 3; the powder bed 4 is arranged on the preheating forming platform 2. Exemplarily, the preheating forming platform 2 adopted by the utility model includes a heating module 21 and a cooling module 23 arranged in sequence from top to bottom; the cooling module 23 is fixedly arranged on the Z-axis lifting device 3 through the heating and sealing module 24 and moves synchronously with the Z-axis lifting device 3; the powder bed 4 includes a powder bed bottom plate 41, which is used as a printing area consumable, and the upper surface is a forming area with high flatness. The heating module 21 heats the medium used for additive on the powder bed bottom plate 41. In addition, when the cooling module 23 is in a state of high cooling efficiency, a heat insulation module 22 can be added between the heating module 21 and the cooling module 23 to improve the heating efficiency. The material of the heat insulation module 22 includes but is not limited to heat insulation materials such as silicon nitride and aluminum silicate, which mainly isolate the upper temperature, so that the heating module 21 will only heat the powder to prevent the temperature of the remaining parts of the cylinder from rising. The cooling module 23 includes but is not limited to cooling structures such as water-cooled plates, air-cooled plates, and semiconductor refrigeration plates. The water-cooled plate is a metal plate with a built-in flow channel, which can be connected to a water cooler for refrigeration; the air-cooled plate is a metal plate with a hollow structure, on which a fan can discharge heat through the flow channel; the semiconductor refrigeration plate is a semiconductor structure, which can be cooled after power is turned on, and the cooling efficiency is extremely high. The heating and sealing module 24 includes but is not limited to components such as springs, pressure plates, and high-temperature resistant felts to prevent the powder from falling along the gap between the preheating forming platform and the insulation forming cylinder, realize linear dynamic sealing, reduce the amount of powder used, and thus reduce printing costs. The modules of the preheating forming platform 2 are mutually connected by screws, and the whole is fixed to the Z-axis lifting device 3 by screws, and can perform piston motion with the insulation forming cylinder.

[0029] See also Figure 7, the cooling module 23 can be directly connected to the heating module 21 by screws. At this time, the temperature sensor 218 is set in the heating module 21, in the forming chamber, or in other positions closer to the powder, and the current on-off device 219 is placed outside the heating module 21 and connected to the temperature sensor 218 by wires. The heating module 21 uses the temperature sensor 218 as temperature feedback, turns heating on and off through the current on-off device 219, and at the same time, lowers the temperature through the cooling module 23, performs PID temperature regulation, and keeps the powder temperature at a constant value.

[0030] The heating module 21 may be heated in various ways. For example, it may be one or more of a resistance wire heating component, a coil heating component or a laser heating component.

[0031] See also Figure 3 as well as Figure 4 When the heating module 21 is a resistance wire heating component, the heating module 21 is a metal plate with a resistance wire embedded therein. When current is applied, the resistance wire in the heating module 21 can generate heat and transfer heat through the metal plate to achieve a heating function. The resistance wire can be wound into a single ring structure or a multi-ring structure. Of course, it can also be wound into other shapes, and the utility model does not limit this.

[0032] See also Figure 5 When the heating module 21 is a coil heating component, the heating module 21 includes a high-frequency coil 211; the high-frequency coil 211 is arranged around the side wall of the heat-insulating forming cylinder 1; the high-frequency coil 211 can directly heat the powder on the powder bed 4 through the forming cylinder, and the heating efficiency is much greater than the resistance wire heating method.

[0033] See also Figure 6When the heating module 21 is a laser heating component, the heating module 21 includes a laser light source 212, a collimating module 213, a reflecting module 214, a homogenizing module 215, a focusing module 216 and an aperture module 217; the collimating module 213, the reflecting module 214, the homogenizing module 215, the focusing module 216 and the aperture module 217 are sequentially arranged on the exit light path of the laser light source 212 from front to back; the laser after passing through the aperture module 217 is irradiated on the powder bed 4. Among them, the laser light source 212 includes but is not limited to a single-mode light source and a multi-mode light source, and the exit light of the laser light source 212 is directly connected to the collimating module 213 (exemplarily, a collimating mirror or a collimating mirror group can be used), and the collimating module 213 outputs a parallel light source and then enters the reflecting module 214 (exemplarily, a reflecting mirror can be used), and the core of the reflecting module is a reflecting mirror, which functions to fold the light path and facilitate the layout of components. The outgoing light of the reflection module 214 is incident on the homogenization module 215. The structure of the homogenization module 215 includes but is not limited to the DOE element and the packaging shell. The packaging shell is screwed to the top plate above the powder bed 4. The function of the homogenization module 215 is to homogenize the light source through multiple groups of micro lenses to reduce the energy concentration of the light source. The focusing module 216 is behind the homogenization module 215 and is also screwed to the top plate above the powder bed 4. In particular, the aperture module 217 is installed above the powder bed 4 and can be fixed by an up and down adjustment mechanism. At the same time, the up and down height of the aperture module 217 can be adjusted with the movement of the up and down adjustment structure to control the amplitude and shape of the outgoing light. Finally, the light source acts on the powder bed 4 and preheats the surface of the powder bed 4 by laser. The laser heating component can be used in combination with the resistance wire heating component and / or the coil heating component to improve the powder preheating efficiency.

[0034] See also Figure 8The heat-insulating forming cylinder 1 provided by the utility model comprises an inner cylinder 11, an intermediate cylinder and an outer cylinder 15; the inner cylinder 11, the intermediate cylinder and the outer cylinder 15 are coaxially mounted in sequence from the inside to the outside; the Z-axis lifting device 3 is placed inside the inner cylinder 11 along the axial direction of the inner cylinder 11 and can be lifted and lowered freely in the inner cylinder 11; a vacuum layer 12 is formed between the inner cylinder 11 and the intermediate cylinder (exemplarily, an airtight space is formed by welding and a sealing ring, and the vacuum is achieved by extracting the air for heat preservation). The inner cylinder 11 and the preheating forming platform 2 form a powder bed area. A reflective heat-insulating layer 13 is provided on the inner wall of the intermediate cylinder, which can achieve the effect of heat preservation by reflecting heat radiation. An air flow channel or a water-cooling flow channel 14 is provided between the intermediate cylinder and the outer cylinder 15, and an opening connected to the air flow channel or a flow channel joint 16 connected to the water-cooling flow channel 14 is provided on the cylinder wall of the outer cylinder 15. Exemplarily, the water-cooling channel 14 can be a spiral groove arranged on the side wall of the middle cylinder. After the middle cylinder and the outer cylinder are fitted together, the spiral groove forms the water-cooling channel 14. The circulating coolant or liquid water can be injected into the water-cooling channel 14 to ensure that the temperature inside the cylinder does not affect the external temperature. When an air channel is used, the circulation of air ensures that the temperature inside the cylinder does not affect the external temperature. Annular heat insulation plates 18 are arranged at both ends of the insulation forming cylinder 1; the annular heat insulation plates 18 cover the ends of the inner cylinder 11, the middle cylinder and the outer cylinder 15; and an insulation sealing module 17 is arranged between the ends of the outer cylinder 15 and the annular heat insulation plates 18. The outer cylinder 15 is an insulation layer, which serves as the last barrier for insulation. The material of the outer cylinder 15 includes but is not limited to heat-resistant materials such as aluminum silicate.

[0035] When the additive manufacturing forming device provided by the utility model is used, the powder is first spread on the bottom plate of the powder bed, and then the powder preheating temperature is determined, the heating module and the cooling module are turned on, and the powder temperature rises immediately. When it is close to the target value, the heating module can be continuously turned on and off by the PLC-controlled current switching device according to the feedback result of the temperature sensor to adjust the powder temperature; in another embodiment, the on and off of the cooling module can also be controlled at the same time, and the PID adjustment of the powder temperature is performed by adjusting the heating module and the cooling module at the same time, so that the powder temperature is maintained at a constant value and the powder preheating is completed; the vacuum layer of the heat-insulating forming cylinder draws out the air to keep the powder in the cylinder warm, and the external flow channel is cooled by water at the same time to ensure the temperature of the other components on the equipment end; printing starts, the forming platform continues to descend, the height of the part continues to increase, and printing is completed.

Claims

1. An additive manufacturing forming device, characterized in that: The additive manufacturing forming device comprises a heat-insulating forming cylinder (1), a Z-axis lifting device (3) and a powder bed (4); the Z-axis lifting device (3) is arranged inside the heat-insulating forming cylinder (1) along the axial direction of the heat-insulating forming cylinder (1) and can be freely lifted and lowered in the heat-insulating forming cylinder (1); the powder bed (4) is arranged on the Z-axis lifting device (3) along the radial direction of the heat-insulating forming cylinder (1) and moves synchronously with the Z-axis lifting device (3).

2. The additive manufacturing forming device according to claim 1, characterized in that: The heat-insulating forming cylinder (1) comprises an inner cylinder (11), an intermediate cylinder and an outer cylinder (15); the inner cylinder (11), the intermediate cylinder and the outer cylinder (15) are coaxially mounted in sequence from the inside to the outside; the Z-axis lifting device (3) is placed inside the inner cylinder (11) along the axial direction of the inner cylinder (11) and can be lifted and lowered freely in the inner cylinder (11); a vacuum layer (12) is formed between the inner cylinder (11) and the intermediate cylinder.

3. The additive manufacturing forming device according to claim 2, characterized in that: A reflective heat-insulating layer (13) is provided on the inner wall of the intermediate tube.

4. The additive manufacturing forming device according to claim 3, characterized in that: An air flow channel or a water cooling flow channel (14) is provided between the intermediate cylinder and the outer cylinder (15), and an opening communicating with the air flow channel or a flow channel joint (16) communicating with the water cooling flow channel (14) is provided on the cylinder wall of the outer cylinder (15).

5. The additive manufacturing forming device according to claim 4, characterized in that: Annular heat insulation plates (18) are provided at both ends of the heat-insulating forming cylinder (1); the annular heat insulation plates (18) cover the ends of the inner cylinder (11), the middle cylinder and the outer cylinder (15); and a heat-insulating sealing module (17) is provided between the ends of the outer cylinder (15) and the annular heat insulation plates (18).

6. The additive manufacturing forming device according to claim 1, 2, 3, 4 or 5, characterized in that: The additive manufacturing forming device also includes a preheating forming platform (2); the preheating forming platform (2) is arranged on a Z-axis lifting device (3) along the radial direction of the heat-insulating forming cylinder (1) and moves synchronously with the Z-axis lifting device (3); and the powder bed (4) is arranged on the preheating forming platform (2).

7. The additive manufacturing forming device according to claim 6, characterized in that: The preheating forming platform (2) comprises a heating module (21) and a cooling module (23) which are arranged in sequence from top to bottom; the cooling module (23) is fixedly arranged on the Z-axis lifting device (3) through a heating sealing module (24) and moves synchronously with the Z-axis lifting device (3); the powder bed (4) comprises a powder bed bottom plate (41); and the heating module (21) heats the medium used for adding materials on the powder bed bottom plate (41).

8. The additive manufacturing forming device according to claim 7, characterized in that: The preheating forming platform (2) further comprises a temperature sensor (218) and a current on-off device (219); the temperature sensor (218) is disposed inside the heating module (21); and the current on-off device (219) is disposed outside the heating module (21) and is connected to the temperature sensor (218) via a wire.

9. The additive manufacturing forming device according to claim 8, characterized in that: The preheating forming platform (2) further comprises a heat insulation module (22) arranged between the heating module (21) and the cooling module (23).

10. The additive manufacturing forming device according to claim 9, characterized in that: The heating module (21) is one or more of a resistance wire heating component, a coil heating component or a laser heating component; the cooling module (23) is one or more of a water cooling structure, an air cooling structure or a semiconductor refrigeration cooling structure.

Images