Forced limiting 3D printing mold

Abstract

The utility model provides a forced limiting 3D printing mold, and belongs to the technical field of machinery. The problem that in the prior art, the operation cost is high is solved. The forced limiting 3D printing mold comprises a lower mold body and an upper mold body, after the upper mold body is connected to the upper portion of the lower mold body in a buckled mode, a semi-finished product workpiece can be positioned between the upper mold body and the lower mold body, a through forming hole is formed in the upper mold body, a temperature control structure is further arranged on the upper mold body, the upper mold body can be kept at the set temperature under the action of temperature control, and therefore the forcible limiting effect is achieved. The lower die body is further provided with a temperature control structure, and the lower die body can be kept at the set temperature under the action of the temperature control structure. The forced limiting 3D printing mold is stable in buckling, temperature adjustment and control are convenient, and the size precision and the forming quality of overall additive forming are improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of machinery and relates to a forced limiting 3D printing mold. Background Art

[0002] DMD (Direct Metal Deposition) is an additive manufacturing technology, also known as a 3D printing technology. It is mainly used to manufacture metal parts, especially those that require high precision and complex geometries.

[0003] DMD technology deposits metal powder layer by layer and melts it to form metal layers, ultimately constructing three-dimensional solid parts.

[0004] Specifically: The DMD process usually uses laser as a heat source, and uses a high-power laser beam to locally melt the metal powder and deposit it onto the substrate or the previous metal layer, stacking layer by layer to form the required three-dimensional structure.

[0005] In the existing DMD molding process, the laser nozzle is directly used in conjunction with a powder feeding mechanism for material addition. In order to form a specific structure, multiple independent movements, including translation and deflection, are required. The entire operation process has the following defects:

[0006] 1. During the entire operation process, there is a lack of limit on the operating area of the laser nozzle, resulting in poor accuracy of the additive process, which is not suitable for additive manufacturing of precision parts;

[0007] 2. During the operation, the product lacks temperature control or has poor temperature control sensitivity, and cannot be programmed to perform temperature (heating, cooling) control according to environmental and process requirements;

[0008] 3. The lack of heat dissipation conduction settings for the structure after additive manufacturing affects the internal organizational structure and thus affects the structural strength.

[0009] In order to overcome the above-mentioned defects and facilitate the promotion of the DMD process, the present application provides an auxiliary limiting structure for use in DMD molding. Utility Model Content

[0010] The first purpose of the present invention is to provide a forced limit 3D printing mold that takes into account both operating efficiency and operating costs in order to address the above-mentioned problems existing in the prior art.

[0011] The second purpose of the present invention is to provide a forced limit 3D printing process.

[0012] The first object of the utility model can be achieved by the following technical solutions:

[0013] A forced limit 3D printing mold includes a lower mold body and an upper mold body, and is characterized in that the upper mold body can position the semi-finished workpiece between the upper mold body and the lower mold body after being snap-fitted and connected to the upper part of the lower mold body. The upper mold body has a through forming hole, and the upper mold body also has a temperature control structure, which can keep the upper mold body at a set temperature under the action of temperature control. The lower mold body also has a temperature control structure, which can keep the lower mold body at a set temperature under the action of the temperature control mechanism.

[0014] In the above-mentioned forced limit 3D printing mold, the temperature control mechanism includes a heating mechanism, and the heating mechanism includes several electric heating rods. The heating ends of the above-mentioned electric heating rods are embedded in the upper mold body and the lower mold body, and the electrical connection ends of the electric heating rods are located outside the upper mold body and the lower mold body and are used to connect to the wires.

[0015] In the above-mentioned forced limit 3D printing mold, the temperature control mechanism also includes a refrigeration mechanism, and the refrigeration mechanism includes cooling channels opened inside the upper mold body and the lower mold body, and the two ends of the cooling channel are respectively an inlet and an outlet.

[0016] In the above-mentioned forced limit 3D printing mold, the above-mentioned cooling channel and the inlet and outlet on the lower mold body that are connected to the cooling channel form a cooling unit, and the number of the cooling units is several.

[0017] In the above-mentioned forced limit 3D printing mold, temperature sensors are correspondingly provided in the above-mentioned upper mold body and lower mold body. The temperature sensors have reserved external wiring and are connected to an external control computer. The control computer controls the temperature of the area corresponding to the working conditions of the electric heating rod and the cooling unit by comparing the detected temperature of the temperature sensor with the required temperature.

[0018] In the above-mentioned forced limit 3D printing mold, the forming hole includes an avoidance part and a forming part. The above-mentioned avoidance part is conical and the large-size end of the avoidance part is located at the upper part of the upper mold body. The forming part is located at the lower part of the upper mold body and the forming part is connected to the avoidance part.

[0019] In the above-mentioned forced limit 3D printing mold, the size of the lower port of the avoidance portion is larger than the size of the forming portion.

[0020] In the above-mentioned forced limit 3D printing mold, the upper mold body includes a flat working part and a frame-shaped frame. The above-mentioned working part is fixedly connected in the frame and has a heat insulation positioning structure between the working part and the frame. When the upper mold body is buckled and connected to the lower mold body, the outer side of the frame is flush with the outer side of the lower mold body.

[0021] In the above-mentioned forced-limit 3D printing mold, the size of the working part is smaller than the inner size of the frame, the above-mentioned heat-insulating positioning structure includes a limiting edge protruding from the inner side of the frame, and the above-mentioned working part is fixedly connected to the limiting edge.

[0022] In the above-mentioned forced limit 3D printing mold, the limit edge is located on one side inside the frame, one edge of the above-mentioned working part is connected to the limit edge, and the side of the above-mentioned limit edge has a protruding connecting section, and the two ends of the connecting section are respectively fixedly connected to the limit edge and the working part.

[0023] In the above-mentioned forced limit 3D printing mold, the thickness dimension of the frame is equal to the thickness dimension of the working part and the two are flush, the above-mentioned limit edge is located at the bottom of the frame and the thickness dimension of the limit edge is smaller than the thickness dimension of the frame, and the inner side of the frame has a protruding connecting block along its length direction, one side of the above-mentioned limit edge is fixedly connected to several connecting blocks, and the above-mentioned connecting section is located on the other side of the limit edge.

[0024] In the above-mentioned forced limit 3D printing mold, the lower part of the working part has a protruding connecting edge, the two ends of the above-mentioned connecting section are respectively connected to the limit edge and the connecting edge, and the length of the connecting section is smaller than the length of the limit edge.

[0025] In the above-mentioned forced limit 3D printing mold, the limit edge is located on one side inside the frame, one edge of the above-mentioned working part is connected to the limit edge, and the side of the above-mentioned limit edge has a protruding connecting section, and the two ends of the connecting section are respectively fixedly connected to the limit edge and the working part.

[0026] In the above-mentioned forced limit 3D printing mold, the thickness dimension of the frame is equal to the thickness dimension of the working part and the two are flush, the above-mentioned limit edge is located at the bottom of the frame and the thickness dimension of the limit edge is smaller than the thickness dimension of the frame, and the inner side of the frame has a protruding connecting block along its length direction, one side of the above-mentioned limit edge is fixedly connected to several connecting blocks, and the above-mentioned connecting section is located on the other side of the limit edge.

[0027] The second purpose of the present invention can be achieved through the following technical solutions:

[0028] A forced limit 3D printing process, characterized in that the process includes the following steps:

[0029] A. Preparation: Prepare the semi-finished workpiece to be processed, polish and clean it, and select the corresponding mold;

[0030] B. DMD molding: The polished and cleaned workpiece is placed between the upper mold and the lower mold. At this time, the upper part of the workpiece is tightly attached to the lower part of the upper mold. The mold with the workpiece is placed on the DMD working device. The metal powder melts and deposits at the molding hole to form the corresponding set structure on the workpiece.

[0031] C. Auxiliary operation: While the DMD operating device is operating, the heating mechanism at the upper mold body keeps the upper mold body at a relatively high set temperature, and the cooling mechanism at the lower mold body keeps the lower mold body at a relatively low set temperature;

[0032] D. Demolding: After the DMD molding operation is completed, the upper mold body and the lower mold body are separated, the molded workpiece is taken out, and then the set structure formed on the workpiece is deburred;

[0033] E. External treatment: After deburring, the workpiece is subjected to surface treatment to obtain the finished workpiece.

[0034] In the above-mentioned forced position limiting 3D printing process, the surface treatment in step E is shaping and sandblasting.

[0035] Compared with the existing technology, this forced-limit 3D printing mold can control the condensation speed in different printing situations because the upper mold body can maintain a relatively high set temperature and the lower mold body can maintain a relatively low set temperature during the workpiece molding process. It can avoid the increase in thermal deformation and stress caused by turbulence and heat accumulation in the thickness direction, and the molding stability of the workpiece is relatively high.

[0036] At the same time, this process is performed on a local position of the semi-finished workpiece. Compared with full 3D printing, its operation efficiency is high and the operation cost is relatively low.

[0037] In addition, since the upper mold body is flush with the lower mold body, no additional alignment operation is required when the upper and lower mold bodies are buckled together. The mold closing is fast and stable, which can appropriately increase the operating speed. The heat-insulating positioning structure can not only properly position the workpiece, but also prevent the heat from the working part from being transferred to the frame too quickly, further improving its stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the three-dimensional structure of the forced limit 3D printing mold.

[0039] Figure 2 This is a schematic diagram of the top view of the forced limit 3D printing mold.

[0040] Figure 3 This is a schematic diagram of the cross-sectional structure of the forming hole in the forced limit 3D printing mold.

[0041] In the figure, 1, upper mold body; 1a, frame; 1a1, limit edge; 1a2, connecting block; 1b, working part; 1b1, forming hole; 1b11, avoidance part; 1b12, forming part; 1b2, connecting edge; 1c, connecting section; 2, lower mold body; 3, electric heating rod. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0043] It should be noted that when a component is referred to as being "mounted on" another component, it may be mounted directly on the other component or there may be a central component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a central component. When a component is considered to be "fixed to" another component, it may be directly fixed to the other component or there may be a central component.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of this invention are intended only to describe specific embodiments and are not intended to limit this invention. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0045] Example 1

[0046] like Figure 1 and Figure 2 As shown, the forced limit 3D printing mold includes two mold bodies that cooperate with each other, such as a lower mold body 1 and an upper mold body 2. After the upper mold body 1 is snap-fitted and connected to the upper part of the lower mold body 2, the semi-finished workpiece can be positioned between the upper mold body 1 and the lower mold body 2. The upper mold body 1 has a through forming hole 1b1, and the upper mold body 1 also has a heating mechanism, which can maintain the set temperature of the upper mold body 1 at 200°C to 300°C under the action of the heating mechanism. The lower mold body 2 also has a refrigeration mechanism, which can maintain the set temperature of the lower mold body 2 at -20°C to 20°C under the action of the refrigeration mechanism.

[0047] The heating temperature can be selected from any of 200° C., 210° C., 220° C., 230° C., 240° C., 250° C., 260° C., 270° C., 280° C., 290° C., and 300° C. Of course, any temperature value other than the above examples within the temperature range can also be selected, and this embodiment does not list them all.

[0048] The cooling temperature can be selected from any of the following temperature values: -20°C, -15°C, -10°C, -5°C, 0°C, 5°C, 10°C, 15°C, and 20°C. Of course, any temperature value other than the above examples within the temperature range can also be selected, and this embodiment does not list them all.

[0049] The semi-finished workpiece is in the shape of a plate, and this mold is used to form a corresponding three-dimensional part structure on the semi-finished workpiece.

[0050] After the upper mold body 1 and the lower mold body 2 are snap-fitted together, the workpiece is positioned between the upper mold body 1 and the lower mold body 2 .

[0051] The positioned workpiece enters the 3D printing operation area along with the mold. When the printing operation is performed at the forming hole, the heating mechanism keeps the upper mold body 1 at a relatively high set temperature, and the cooling mechanism keeps the lower mold body 2 at a relatively low set temperature.

[0052] This can control the condensation speed at the printing location of the forming hole 1b, avoid turbulence in the thickness direction and increased thermal deformation and stress caused by heat accumulation, and ultimately improve the yield rate.

[0053] The heating mechanism includes a plurality of electric heating rods 3 , the heating ends of the electric heating rods 3 are embedded in the upper mold body 1 , and the electrical connection ends of the electric heating rods 3 are located outside the upper mold body 1 and are used to connect to the wires.

[0054] The electric heating rod 3 after being energized can raise the temperature of the upper mold body 1 to a set preset temperature.

[0055] The refrigeration mechanism includes a cooling channel opened inside the lower mold body 2 , with an inlet and an outlet at both ends of the cooling channel, and the inlet and the outlet are located at the edge of the lower mold body 2 .

[0056] The cooling channel and the inlet and outlet on the lower mold body 2 that communicate with the cooling channel form a cooling unit, and the number of the cooling units is several.

[0057] The cooling medium can reduce the temperature of the lower mold body to a relatively low level during the passage of the cooling medium through the cooling channel. In this embodiment, the cooling medium is a liquid coolant.

[0058] Furthermore, the contact surfaces of the upper mold body 1, the lower mold body 2 and the product are provided with several temperature zones, the electric heating rod 3 and the cooling mechanism can independently heat and cool each temperature zone, and a cold bridge is provided between each temperature zone.

[0059] like Figure 1 and Figure 3As shown, the forming hole 1b1 includes an avoidance portion 1b11 and a forming portion 1b12. The avoidance portion 1b11 is conical and the large-size end of the avoidance portion 1b11 is located at the upper part of the upper mold body 1. The forming portion 1b12 is located at the lower part of the upper mold body 1 and the forming portion 1b12 is connected to the avoidance portion 1b11.

[0060] The size of the lower port of the avoidance portion 1b11 is larger than that of the forming portion 1b12.

[0061] The avoidance portion 1b11 enables the 3D printing device to smoothly extend into the forming portion 1b12 , thereby preventing the 3D printing device from being blocked by the upper mold body 1 .

[0062] The upper mold body 1 includes a flat working part 1b and a frame-shaped border 1a. The above-mentioned working part 1b is fixedly connected to the inner a of the border 1a and has a heat insulation positioning structure between the working part 1b and the border 1a. When the upper mold body 1 is buckled and connected to the lower mold body 2, the outer side of the border is flush with the outer side of the lower mold body 2.

[0063] Furthermore, a limiting platform is provided at the mouth of the forming hole 1b1. When the limiting structure adopts an extruded profile, the profile is correspondingly inserted into the forming hole 1b1 and pressed against by the limiting platform.

[0064] The thermal insulation positioning structure has two functions:

[0065] First, since the electric heating rod 3 is connected to the working part 1b, it can prevent the high temperature of the working part 1b from being transferred to the frame 1a too quickly;

[0066] Secondly, it has an appropriate positioning effect on the workpiece, which can ensure the positioning stability of the workpiece in the mold.

[0067] The size of the working part 1b is smaller than the inner size of the frame 1a. The above-mentioned heat insulation positioning structure includes a limiting edge 1a1 protruding from the inner side of the frame 1a. The above-mentioned working part 1b is fixedly connected to the limiting edge 1a1.

[0068] The limiting edge 1a1 is located at one side inside the frame 1a, and one edge of the working part 1b is connected to the limiting edge 1a1. The side of the limiting edge 1a1 has a protruding connecting section 1c, and the two ends of the connecting section 1c are respectively fixed to the limiting edge 1a1 and the working part 1b.

[0069] The workpiece has a protruding flange structure, and the limiting edge 1a1 matches the flange. After the limiting edge 1a1 is matched and connected with the flange on the workpiece, the workpiece can be stably positioned in the mold.

[0070] At the same time, the two ends of the connecting section 1c are connected to the limiting edge 1a1 and the working part 1b respectively. Since the connecting section 1c is a small part, it can minimize the heat from the working part from being transferred to the frame 1a too quickly. At the same time, it can also stably connect the frame 1a and the working part 1b.

[0071] The thickness of the frame 1a is equal to the thickness of the working part 1b and the two are flush. The above-mentioned limiting edge 1a1 is located at the bottom of the frame 1a and the thickness of the limiting edge 1a1 is smaller than the thickness of the frame 1a. The inner side of the frame 1a has a protruding connecting block 1a2 along its length direction. One side of the above-mentioned limiting edge 1a1 is fixedly connected to several connecting blocks 1a2, and the above-mentioned connecting section 1c is located on the other side of the limiting edge 1a1.

[0072] The lower part of the working part 1b has a protruding connecting edge 1b2, and the two ends of the connecting section 1c are respectively connected to the limiting edge 1a1 and the connecting edge 1b2. The length of the connecting section 1c is smaller than that of the limiting edge 1a1.

[0073] The provision of connecting block 1a2 further reduces heat conduction. Furthermore, the frame 1a, connecting block 1a2, stopper 1a1, connecting section 1c, and connecting edge 1b2 form an integrated structure. This improves the structural compactness of upper mold body 1. The relatively small thickness of stopper 1a1, connecting section 1c, and connecting edge 1b2 further reduces heat conduction between working portion 1b and frame 1a. Furthermore, the thin, thin shape of stopper 1a1, connecting section 1c, and connecting edge 1b2 provides excellent heat dissipation.

[0074] The forced position limit 3D printing process includes the following steps:

[0075] A. Preparation: Prepare the semi-finished workpiece to be processed, polish and clean it, and select the corresponding mold;

[0076] B. DMD molding: The polished and cleaned workpiece is placed between the upper mold and the lower mold. At this time, the upper part of the workpiece is tightly attached to the lower part of the upper mold. The mold with the workpiece is placed on the DMD working device. The metal powder melts and deposits at the molding hole to form the corresponding set structure on the workpiece.

[0077] C. Auxiliary operation: While the DMD operating device is operating, the heating mechanism at the upper mold body keeps the upper mold body at a relatively high set temperature, and the cooling mechanism at the lower mold body keeps the lower mold body at a relatively low set temperature;

[0078] D. Demolding: After the DMD molding operation is completed, the upper mold body and the lower mold body are separated, the molded workpiece is taken out, and then the set structure formed on the workpiece is deburred;

[0079] E. External treatment: The deburred workpiece is subjected to surface treatment to obtain a finished workpiece. In this embodiment, the surface treatment includes shaping and sandblasting.

[0080] The operating area of this forced-limited 3D printing process is the forming hole of the upper mold body. It can be understood that the printing operation is carried out at the set position of the semi-finished workpiece. The printing operation is forced to be limited by the forming hole, which can ensure that the corresponding part structure is stably formed at the set position of the semi-finished workpiece.

[0081] During the printing process, since the upper template has a relatively high temperature and the lower template has a relatively low temperature, the printing operation area is subjected to the above-mentioned effects, which can avoid the condensation speed of the part structure at the printing operation area, avoid the increase in thermal deformation and stress caused by turbulence and heat accumulation in the thickness direction, and ultimately effectively improve the printing effect.

[0082] In this embodiment, the mold is tested for DMD before operation. The test conditions are:

[0083] Base plate: 3mm7075 aluminum alloy;

[0084] Aluminum wire: ER7075, D=1.2mm;

[0085] Protective gas: xenon 5L / min;

[0086] Scanning speed: 40mm / s;

[0087] Laser power: 2600W;

[0088] Wire feeding speed: 1600mm / min;

[0089] Taking 3C metal casings as an example, batch operations will only be carried out after 3D printing operations can be stably achieved.

[0090] This process has the following characteristics:

[0091] (1) Faster deposition rate

[0092] For a deposition wall without forced limited cooling and heating, in the early stages of deposition, the molten pool dynamically flows toward the sides due to contact with air on both sides, with the molten pool flowing faster toward the sides than toward the center. In the middle and late stages of deposition, the dynamic flows toward the center and toward the sides reach a dynamic equilibrium. Therefore, the deposition velocity of the deposition wall gradually decreases in the early stages and remains essentially constant after reaching equilibrium. The average deposition height per deposition cycle is 4.2 mm.

[0093] For deposition walls with forced, limited cooling and heating, the presence of side restraints throughout the deposition process limits the dynamic flow of the molten pool to the sides, allowing dynamic backflow toward the center, concentrating the molten pool within a defined spatial region. Consequently, the deposition rate of the deposition wall remains essentially constant throughout the entire process, and the average deposition rate is greater than that of a wall without forced, limited cooling.

[0094] The upper and lower mold bodies are heated to 250° C. by the heating mechanism, and cooled to 0° C. by the cooling mechanism. In a unit deposition cycle, the deposition height is 5.2 mm.

[0095] (2) Higher utilization rate of deposited materials

[0096] For the deposition wall without forced limited cooling and heating, the lack of forced limited cooling resulted in a low material utilization rate. Along the height of the deposition wall, the side depressions and convexities were more severe, with an average material utilization rate of 78.2%.

[0097] For the deposition wall with forced limited cooling and heating, the forced limited position resulted in a high material utilization rate. Along the height of the deposition wall, the side depressions and convexities were not noticeable, resulting in a material utilization rate of 83.2%.

[0098] (3) Better deposition quality

[0099] Without forced limited cooling and heating of the deposition wall, the lower side of the deposition wall, due to the initial stage of the deposition process, has a low cumulative heat input and a high pore escape rate, resulting in a low degree of porosity. In the middle of the deposition wall, due to the intermediate stage of the deposition process, the cumulative heat input increases, the pore escape rate slows, and the porosity increases. At the upper side of the deposition wall, due to the final stage of the deposition process, the cumulative heat input is the highest, the pore escape rate is the slowest, and the porosity is the highest.

[0100] The forced limited cooling and heated deposition wall are used. Due to the forced limited cooling process, heat transfer through the wall is faster during deposition, the cumulative effect of heat input to the deposition wall is less pronounced, the porosity of the deposition wall is faster, and the porosity level remains relatively low and consistent. This alleviates the porosity defect in the deposition wall.

[0101] Example 2

[0102] The operation process of this embodiment is the same as that of the first embodiment, except that the temperatures of the upper mold body and the lower mold body are changed.

[0103] This process has the following characteristics:

[0104] (1) Faster deposition rate

[0105] For a deposition wall without forced limited cooling and heating, in the early stages of deposition, the molten pool dynamically flows toward the sides due to contact with air on both sides, with the molten pool flowing faster toward the sides than toward the center. In the middle and late stages of deposition, the dynamic flows toward the center and toward the sides reach a dynamic equilibrium. Therefore, the deposition velocity of the deposition wall gradually decreases in the early stages and remains essentially constant after reaching equilibrium. The average deposition height per deposition cycle is 4.2 mm.

[0106] For deposition walls with forced, limited cooling and heating, the presence of side restraints throughout the deposition process limits the dynamic flow of the molten pool to the sides, allowing dynamic backflow toward the center, concentrating the molten pool within a defined spatial region. Consequently, the deposition rate of the deposition wall remains essentially constant throughout the entire process, and the average deposition rate is greater than that of a wall without forced, limited cooling.

[0107] The upper and lower mold bodies are heated to 200° C. by the heating mechanism, and cooled to 20° C. by the cooling mechanism. During a unit deposition cycle, the deposition height is 5.4 mm.

[0108] (2) Higher utilization rate of deposited materials

[0109] For the deposition wall without forced limited cooling and heating, the lack of forced limited cooling resulted in a low material utilization rate. Along the height of the deposition wall, the side depressions and convexities were more severe, with an average material utilization rate of 79.3%.

[0110] For the deposition wall with forced limited cooling and heating, the forced limited position resulted in a high material utilization rate. Along the height of the deposition wall, the side depressions and convexities were not noticeable, and the average material utilization rate was 83.2%.

[0111] (3) Better deposition quality

[0112] Without forced limited cooling and heating of the deposition wall, the lower side of the deposition wall, due to the initial stage of the deposition process, has a low cumulative heat input and a high pore escape rate, resulting in a low degree of porosity. In the middle of the deposition wall, due to the intermediate stage of the deposition process, the cumulative heat input increases, the pore escape rate slows, and the porosity increases. At the upper side of the deposition wall, due to the final stage of the deposition process, the cumulative heat input is the highest, the pore escape rate is the slowest, and the porosity is the highest.

[0113] The forced limited cooling and heated deposition wall are used. Due to the forced limited cooling process, heat transfer through the wall is faster during deposition, the cumulative effect of heat input to the deposition wall is less pronounced, the porosity of the deposition wall is faster, and the porosity level remains relatively low and consistent. This alleviates the porosity defect in the deposition wall.

[0114] Example 3

[0115] The operation process of this embodiment is the same as that of the first embodiment, except that the temperatures of the upper mold body and the lower mold body are changed.

[0116] This process has the following characteristics:

[0117] (1) Faster deposition rate

[0118] For a deposition wall without forced limited cooling and heating, in the early stages of deposition, the molten pool dynamically flows toward the sides due to contact with air on both sides, with the molten pool flowing faster toward the sides than toward the center. In the middle and late stages of deposition, the dynamic flows toward the center and toward the sides reach a dynamic equilibrium. Therefore, the deposition velocity of the deposition wall gradually decreases in the early stages and remains essentially constant after reaching equilibrium. The average deposition height per deposition cycle is 4.2 mm.

[0119] For deposition walls with forced, limited cooling and heating, the presence of side restraints throughout the deposition process limits the dynamic flow of the molten pool to the sides, allowing dynamic backflow toward the center, concentrating the molten pool within a defined spatial region. Consequently, the deposition rate of the deposition wall remains essentially constant throughout the entire process, and the average deposition rate is greater than that of a wall without forced, limited cooling.

[0120] The upper and lower mold bodies are heated to 300° C. by the heating mechanism, and cooled to -20° C. by the cooling mechanism. During a unit deposition cycle, the deposition height is 5.1 mm.

[0121] (2) Higher utilization rate of deposited materials

[0122] For the deposition wall without forced limited cooling and heating, the lack of forced limited cooling resulted in a low material utilization rate. Along the height of the deposition wall, the side depressions and convexities were more severe, with an average material utilization rate of 79.2%.

[0123] For the deposition wall with forced limited cooling and heating, the forced limited position resulted in a high material utilization rate. Along the height of the deposition wall, the side depressions and convexities were not noticeable, and the average material utilization rate was 83.2%.

[0124] (3) Better deposition quality

[0125] Without forced limited cooling and heating of the deposition wall, the lower side of the deposition wall, due to the initial stage of the deposition process, has a low cumulative heat input and a high pore escape rate, resulting in a low degree of porosity. In the middle of the deposition wall, due to the intermediate stage of the deposition process, the cumulative heat input increases, the pore escape rate slows, and the porosity increases. At the upper side of the deposition wall, due to the final stage of the deposition process, the cumulative heat input is the highest, the pore escape rate is the slowest, and the porosity is the highest.

[0126] The forced limited cooling and heated deposition wall are used. Due to the forced limited cooling process, heat transfer through the wall is faster during deposition, the cumulative effect of heat input to the deposition wall is less pronounced, the porosity of the deposition wall is faster, and the porosity level remains relatively low and consistent. This alleviates the porosity defect in the deposition wall.

[0127] The various technical features of the above-described embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the various technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0128] Those skilled in the art should recognize that the above embodiments are merely intended to illustrate the present invention and are not intended to limit the present invention. As long as they are within the spirit of the present invention, appropriate changes and modifications to the above embodiments fall within the scope of protection claimed by the present invention.

Claims

1. A forced limit 3D printing mold, comprising a lower mold body (2) and an upper mold body (1), characterized in that: After the upper mold body (1) is snap-fitted and connected to the upper part of the lower mold body (2), the semi-finished workpiece can be positioned between the upper mold body (1) and the lower mold body (2); the upper mold body (1) has a through-molding hole (1b1); the upper mold body (1) also has a temperature control structure, which can keep the upper mold body (1) at a set temperature under the action of temperature control; the lower mold body (2) also has a temperature control structure, which can keep the lower mold body (2) at a set temperature under the action of the temperature control mechanism.

2. The forced position limiting 3D printing mold according to claim 1, characterized in that: The temperature control mechanism includes a heating mechanism, and the heating mechanism includes a plurality of electric heating rods (3). The heating ends of the electric heating rods (3) are embedded in the upper mold body (1) and the lower mold body (2), and the electrical connection ends of the electric heating rods (3) are located outside the upper mold body (1) and the lower mold body (2) and are used to be connected to the wires.

3. The forced position limiting 3D printing mold according to claim 2, characterized in that: The temperature control mechanism further comprises a refrigeration mechanism, which comprises a cooling channel opened inside the upper mold body (1) and the lower mold body (2), with the two ends of the cooling channel being an inlet and an outlet respectively.

4. The forced position limiting 3D printing mold according to claim 3, characterized in that: The cooling channel and the inlet and outlet on the lower mold body (2) that communicate with the cooling channel form a cooling unit, and the number of the cooling units is several.

5. The forced position limiting 3D printing mold according to claim 4, characterized in that: The forming hole (1b1) includes an avoidance portion (1b11) and a forming portion (1b12), wherein the avoidance portion (1b11) is conical and the large-size end of the avoidance portion (1b11) is located at the upper part of the upper mold body (1), and the forming portion (1b12) is located at the lower part of the upper mold body (1) and the forming portion (1b12) is connected to the avoidance portion (1b11).

6. The forced position limiting 3D printing mold according to claim 5, characterized in that: The size of the lower port of the avoidance portion (1b11) is larger than the size of the forming portion (1b12).

7. The forced position limiting 3D printing mold according to claim 6, characterized in that: The upper mold body (1) comprises a flat-plate-shaped working portion (1b) and a frame-shaped border (1a); the working portion (1b) is fixedly connected to the border (1a) and a heat-insulating positioning structure is provided between the working portion (1b) and the border (1a); when the upper mold body (1) is snap-fitted and connected to the outer side of the rear border (1a) of the lower mold body (2), the upper mold body (1) is flush with the outer side of the lower mold body (2).

8. The forced position limiting 3D printing mold according to claim 7, characterized in that: The size of the operating portion (1b) is smaller than the inner size of the frame (1a); the heat-insulating positioning structure comprises a limiting edge (1a1) protruding from the inner side of the frame (1a); and the operating portion (1b) is fixedly connected to the limiting edge (1a1).

9. The forced position limiting 3D printing mold according to claim 8, characterized in that: The limiting edge (1a1) is located at one side of the frame (1a), one side of the operating portion (1b) is connected to the limiting edge (1a1), and the side of the limiting edge (1a1) has a protruding connecting section (1c), and the two ends of the connecting section (1c) are respectively fixed to the limiting edge (1a1) and the operating portion (1b).

10. The forced position limiting 3D printing mold according to claim 9, characterized in that: The thickness of the frame (1a) is equal to that of the working portion (1b), and the two are flush. The limiting edge (1a1) is located at the bottom of the frame (1a), and the thickness of the limiting edge (1a1) is smaller than the thickness of the frame (1a). The inner side of the frame (1a) has a protruding connecting block (1a2) along its length direction. One side of the limiting edge (1a1) is fixedly connected to a plurality of connecting blocks (1a2), and the connecting section (1c) is located on the other side of the limiting edge (1a1).

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