High vacuum die casting extrusion composite process

Abstract

The application discloses a high-vacuum die-casting extrusion composite process, characterized in that at least one extrusion rod and at least one extrusion groove communicated with a cavity are arranged on a movable die of a mold, and then the die-casting is carried out through the following steps: step one, a die-casting machine is used for clamping the mold; step two, the cavity is vacuumized; when the vacuum degree in the cavity reaches a set value, molten alloy is injected into the cavity; step three, the extrusion rod is pushed to make the end of the extrusion rod continuously extend into the extrusion groove, the molten alloy in the extrusion groove is extruded, and then the molten alloy in the cavity is extruded, so that the molten alloy in the cavity is further compacted; and step four, cooling and setting, and then the mold is opened, and the formed die-casting part is pushed out. The application can solve the problem that a small amount of pores and loose parts still exist in the die-casting part in the vacuum die-casting, and a die-casting part with higher quality is obtained.

Description

Technical Field

[0001] This invention relates to die casting technology for metal die castings, specifically to a high-vacuum die casting extrusion composite process. Background Technology

[0002] Die castings are widely used in various industries, such as aerospace, automobiles, and shipbuilding. However, due to the tendency for residual gas to remain inside the die castings during the production process, defects such as porosity and looseness occur, preventing the die castings from being machined or heat-treated. This severely affects the mechanical properties of the die castings and limits their application range.

[0003] Currently, to address the aforementioned molding quality issues, the industry commonly employs vacuum die casting technology. This involves evacuating the mold cavity using a vacuum pump before the molten metal alloy is injected into it under high pressure and high speed. Once the required vacuum level is achieved, the molten alloy is injected into the mold, and finally, the liquid alloy is cooled, solidified, and ejected from the mold. For example, the vacuum connection structure for a zinc alloy vacuum die casting mold, previously disclosed in patent application CN206854613U, falls under the category of such a vacuum pumping device.

[0004] The aforementioned vacuum die casting technology has solved the molding defects of porosity and looseness in die castings to a certain extent. However, during the process of injecting molten alloy into the mold, a small amount of air will seep into the cavity under high pressure, resulting in some die castings still having a small amount of porosity and looseness. Summary of the Invention

[0005] The purpose of this invention is to provide a high-vacuum die casting extrusion composite process, which can solve the problem that die castings still have a small amount of porosity and looseness in vacuum die casting, and obtain higher quality die castings.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A high-vacuum die-casting extrusion composite process, characterized by: setting at least one extrusion rod and at least one extrusion groove communicating with the cavity on the moving mold, and then performing die casting through the following steps:

[0008] Step 1: The die-casting machine closes the mold.

[0009] Step two: Evacuate the cavity; once the vacuum level in the cavity reaches the set value, inject the molten alloy into the cavity.

[0010] Step 3: Push the extrusion rod so that the end of the extrusion rod continuously extends into the extrusion groove to extrude the molten alloy in the extrusion groove, thereby extruding the molten alloy in the cavity and further compacting the molten alloy in the cavity;

[0011] Step four: Cool and solidify, then open the mold and eject the formed die-cast part.

[0012] Furthermore, after the molten alloy is injected, a set pressure is continuously applied to the molten alloy in the cavity through the injection port of the mold until step three is completed.

[0013] Furthermore, in step two, during the process of injecting the molten alloy into the mold cavity, the die-casting machine continuously evacuates the mold cavity until the injection of the molten alloy is completed.

[0014] Furthermore, the extrusion groove is located on the channel connecting the cavity and the vacuum channel.

[0015] Furthermore, in step two, after evacuating the cavity once, the vacuum level inside the cavity is checked. If the vacuum level does not reach the set value, the cavity is evacuated again, and this process is repeated until the vacuum level reaches the set value.

[0016] Furthermore, a push plate assembly and an extrusion plate assembly are set in the moving mold of the die. The push rod in the moving mold used to push out the die casting is connected to the push plate assembly, and the extrusion rod is connected to the extrusion plate assembly, so that the push plate assembly and the extrusion plate assembly are linked. In step three, the piston rod of the die casting machine pushes the push plate assembly to drive the extrusion plate assembly forward, which in turn drives the extrusion rod forward to extrude the molten alloy in the extrusion groove. In step four, the piston rod of the die casting machine continues to push the push plate assembly forward to drive the push rod forward, which in turn pushes out the formed die casting.

[0017] Furthermore, the linkage between the pusher assembly and the extrusion plate assembly is achieved as follows: the extrusion plate assembly is located behind the pusher assembly, and the pusher assembly and the extrusion plate assembly are connected by a resin opener / closer. A rubber pad is set at the end of the push rod for buffering, and a stop post is set in the moving mold to limit the forward stroke of the extrusion plate assembly. In step three, the piston rod of the die-casting machine pushes the pusher assembly, which drives the extrusion plate assembly forward through the resin opener / closer, thereby driving the extrusion rod forward to extrude the molten alloy in the extrusion groove. The push rod will remain in place under the buffering effect of the rubber pad. In step four, the piston rod of the die-casting machine continues to push the pusher assembly, and the extrusion plate assembly will stop moving forward under the obstruction of the stop post. The resin opener / closer will gradually disengage from the pusher assembly, and the pusher assembly will push the push rod forward, thereby ejecting the formed die-cast part.

[0018] Furthermore, the push plate assembly includes a push plate and a push rod fixing plate. The push rod fixing plate is fixedly installed on the push plate in a superimposed manner. The push rod passes through the push rod fixing plate. A rubber pad is embedded in the push plate and rests on the head of the push rod.

[0019] Furthermore, the extrusion plate assembly includes an extrusion plate and an extrusion rod fixing plate. The extrusion rod fixing plate is fixedly installed in the extrusion plate in a superimposed manner, and the extrusion rod passes through the extrusion rod fixing plate. The head of the extrusion rod is restricted by the extrusion plate.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. After vacuuming and injecting the molten alloy into the mold cavity, the present invention performs an extrusion operation. The molten alloy in the extrusion groove is extruded by the extrusion rod, which in turn extrudes the molten alloy in the mold cavity, making the molten alloy in the mold cavity more compacted. This forces out any small amount of air that has seeped in, so that the final die casting will not have any pores or looseness, and a higher quality die casting can be obtained.

[0022] 2. Furthermore, after the injection of the molten alloy is completed, the present invention applies pressure to the molten alloy in the cavity until step three is completed, which can better ensure the extrusion effect of the molten alloy in the cavity and further improve the quality of the die casting.

[0023] 3. Furthermore, during the process of injecting the molten alloy into the mold cavity, the present invention continuously evacuates the mold cavity, which can better ensure that there are no air holes or looseness inside the final die casting, thus further improving the quality of the die casting. Attached Figure Description

[0024] Figure 1 This is a flowchart of the high-vacuum die-casting extrusion composite process of the present invention;

[0025] Figure 2 This is one of the perspective views of the mold of the present invention when the fixed mold and the moving mold are separated;

[0026] Figure 3 This is a second perspective view of the mold of the present invention when the fixed mold and the moving mold are separated;

[0027] Figure 4 This is a perspective view of the moving mold side plate of the mold of the present invention when it is disassembled;

[0028] Figure 5 This is a three-dimensional schematic diagram of the mold of the present invention after the mold is connected to the vacuum device and the mold is closed;

[0029] Figure 6 This is a schematic diagram of the assembly structure of the mold after it is connected to the vacuum pumping device in the main view direction.

[0030] Meaning of the labels in the attached diagram:

[0031] 1-Fixed mold plate; 2-Fixed mold insert; 3-Moving mold insert; 4-Push rod; 5-Moving mold plate; 6-Stop post; 7-Rubber pad; 8-Push rod fixing plate; 9-Push plate; 10-Extrusion rod fixing plate; 11-Extrusion plate; 12-Moving mold base plate; 13-Support column; 14-Resin opener / closer; 15-Extrusion rod; 16-Extrusion groove; 17-Vacuum port; 18-Piston rod; 19-Injection port; 20-Cavity; 21-Vacuum channel; 22-Central hole; 23-Upper part of vacuum device; 24-Lower part of vacuum device. Detailed Implementation

[0032] The present invention will be further described below with reference to embodiments.

[0033] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0034] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0035] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution. Example

[0036] The high-vacuum die-casting extrusion composite process of this embodiment is implemented on a hot chamber die-casting machine. It features at least one extrusion rod and at least one extrusion groove communicating with the cavity on the moving mold, followed by the following steps for die casting:

[0037] Step 1: The die-casting machine closes the mold, that is, the moving mold and the fixed mold of the mold are closed together, forming a cavity between the moving mold and the fixed mold;

[0038] Step 2: The vacuum pump controlled by the PLC of the die-casting machine is used to evacuate the cavity. The specific evacuation process is as follows: after evacuating the cavity once, the vacuum level in the cavity is checked. If the vacuum level does not reach the set value, the cavity is evacuated again. This cycle is repeated until the vacuum level reaches the set value.

[0039] Once the vacuum level inside the cavity reaches the set value, the injection system of the die-casting machine is activated, and the molten liquid alloy is injected into the cavity from the injection port of the mold under the action of high injection pressure. During this period, the die-casting machine continuously evacuates the cavity until the injection of the molten alloy is completed. This can minimize air infiltration and further extract most of the infiltrated air, thereby ensuring the quality of the finished product.

[0040] After the molten alloy is injected into the cavity, the extrusion groove will also be filled with molten alloy;

[0041] Step 3: Push the extrusion rod so that the end of the extrusion rod continuously extends into the extrusion groove to extrude the molten alloy in the extrusion groove, and then extrude the molten alloy in the cavity. This further compacts the molten alloy in the cavity, thereby squeezing out the small amount of air that has seeped in from the molten alloy. This ensures that there are no more air holes or looseness inside the final die casting, resulting in a higher quality die casting.

[0042] After the molten alloy is injected, a set pressure is continuously applied to the molten alloy inside the cavity through the injection port of the mold; this is called pressure holding. Specifically, after injection, a set pressure of molten alloy is continuously applied through the injection port to maintain pressure on the molten alloy inside the cavity. The pressure holding period continues until step three is completed. This pressure holding better ensures the extrusion effect of the molten alloy inside the cavity, further improving the quality of the die-casting.

[0043] Step four involves cooling and solidifying the molten alloy in the cavity, then opening the mold (both the moving and fixed molds), and finally ejecting the die-cast part through the push rod in the fixed mold, thus completing one production cycle.

[0044] In this embodiment, the extrusion groove is located on the channel connecting the cavity and the vacuum channel.

[0045] The process flow of the above-mentioned high-vacuum die casting extrusion composite process is as follows: Figure 1 As shown.

[0046] like Figures 2 to 4 The mold shown in this embodiment includes a moving mold and a fixed mold.

[0047] The fixed mold is provided with a fixed template 1 and a fixed mold insert 2. The fixed template 1 is fixedly installed on the die casting machine, and the fixed mold insert 2 is embedded in the fixed template 1. An injection port 19 is provided on the fixed mold for the entry of molten alloy.

[0048] The moving mold includes a moving mold base plate 12, an extrusion plate assembly, a pusher plate assembly, a moving template 5, a moving mold insert 3, a stop post 6, a push rod 4, an extrusion rod 15, a resin opener / closer 14, and a support post 13. The moving mold insert 3 is embedded and fixed in the moving template 5, and the cavity 20 is set on the moving mold insert 3. In this embodiment, only one extrusion groove 16 is provided, located on the channel connecting the cavity 20 and the vacuum channel 21. The extrusion plate assembly and the pusher plate assembly are set between the moving mold base plate 12 and the moving template 5, with the extrusion plate assembly located behind the pusher plate assembly. The support post 13 is supported between the moving mold base plate 12 and the moving template 5. The support post 13 passes through the extrusion plate assembly and the pusher plate assembly, ensuring the strength and rigidity of the mold during the die-casting extrusion process. The stop post 6 is fixedly installed on the inner surface of the moving template 5, passing through the pusher plate assembly, and restricts the forward stroke of the extrusion plate assembly. The push plate assembly and the extrusion plate assembly are connected by a resin opener / closer 14. The resin opener / closer 14 is screwed onto the extrusion plate assembly. The resin opener / closer 14 is a conventional device; the diameter of its resin tube can be adjusted using the screws to create friction with the matching hole, thus achieving the separation and closure of the push plate assembly and the extrusion plate assembly. Both the moving mold base plate 12 and the extrusion plate assembly have central holes 22 for the piston rod 18 of the die-casting machine to pass through.

[0049] The push plate assembly includes a push plate 9 and a push rod fixing plate 8. The push rod fixing plate 8 is stacked on top of the push plate 9 and fixedly connected by bolts. The push rod 4 passes through a first through hole in the push rod fixing plate 8. A first countersunk hole is provided at the end of the first through hole near the push plate 9. The head of the push rod 7 is located in the first countersunk hole. The push plate assembly can drive all the push rods 4 to move together. A rubber pad 7 is provided for each push rod 4. The rubber pad 7 is embedded in the push plate 9 and aligned with the push rod 4. The rubber pad 7 rests on the head of the push rod 4. There are multiple push rods 4, which pass through the moving template 5 and into the bottom of the cavity 20.

[0050] The extrusion plate assembly includes an extrusion plate 11 and an extrusion rod fixing plate 10. The extrusion rod fixing plate 10 is stacked on top of the extrusion plate 11 and fixedly connected by bolts. The extrusion rod 15 passes through a second through hole on the extrusion rod fixing plate 10. A second countersunk hole is provided at the end of the second through hole near the extrusion plate 11. The head of the extrusion rod 15 is confined in the second countersunk hole, so that all the extrusion rods 15 can move together through the extrusion plate assembly. The number of extrusion rods 15 corresponds to the number of extrusion grooves 16. The extrusion rods 15 pass through the moving template 5 and extend to the bottom of the extrusion groove 16.

[0051] In this embodiment, a vacuuming device is also installed on the side of the mold. The upper part 23 and the lower part 24 of the vacuuming device are fixedly installed on the fixed mold and the moving mold, respectively. The vacuuming channel inside the vacuuming device is connected to the cavity 20 inside the mold. The vacuuming port 17 on the side of the vacuuming device is connected to the vacuum pump on the die-casting machine.

[0052] The specific process of this high-vacuum die-casting extrusion composite process using the aforementioned mold is as follows:

[0053] The piston rod 18 of the die-casting machine passes through the central hole 22 and rests against the push plate 9. The mold is closed, the fixed mold insert 2 and the moving mold insert 3 are closed, and the cavity 20 is located between the fixed mold insert 2 and the moving mold insert 3, matching the contour of the die-casting part. The cavity 20 is evacuated by a vacuum pump. When the vacuum level in the cavity 20 reaches the set value, the molten alloy is injected into the cavity 20 through the injection port 19. After injection, the molten alloy in the cavity 20 is continuously pressurized.

[0054] During the pressure holding period, the piston rod 18 of the die-casting machine moves forward, pushing the push plate 9 forward. At this time, the rubber pad 7 is compressed, which plays a buffering role, and the push rod 4 will not move forward. The forward movement of the push plate 9 will drive the extrusion plate assembly forward through the resin opener 14, and then drive the extrusion rod 15 forward to realize the extrusion of the molten alloy in the extrusion groove 16. When the extrusion rod fixing plate 10 hits the stop column 6, the piston rod 18 of the die-casting machine stops moving forward, thus completing the extrusion operation of the molten alloy in the extrusion groove 16.

[0055] After the extrusion operation is completed and the pressure is held for a set time, the molten alloy in the cavity 20 is cooled and solidified, and then the mold is opened. The piston rod 18 of the die-casting machine then continues to advance, further pushing the push plate 9 forward. At this point, because the extrusion rod fixing plate 10 is blocked by the stop post 6, the extrusion plate assembly cannot advance. The resin opener / closer 14 gradually disengages from the push plate assembly, and the rubber pad 7, having been compressed to its limit, pushes the push rod 4 forward, thus ejecting the formed die-cast part, resulting in the die-cast part. This completes one production cycle.

[0056] The above embodiments of the present invention are not intended to limit the scope of protection of the present invention. The implementation of the present invention is not limited thereto. All other modifications, substitutions or alterations made to the above structure of the present invention based on the above content of the present invention, in accordance with ordinary technical knowledge and common practice in the field, without departing from the basic technical idea of ​​the present invention, shall fall within the scope of protection of the present invention.

Claims

1. A high-vacuum die-casting extrusion composite process, characterized in that: At least one extrusion bar and at least one extrusion groove communicating with the cavity are provided on the moving mold of the die, and then die casting is performed through the following steps: Step 1: The die-casting machine closes the mold. Step two: Evacuate the cavity; once the vacuum level in the cavity reaches the set value, inject the molten alloy into the cavity. Step 3: Push the extrusion rod so that the end of the extrusion rod continuously extends into the extrusion groove to extrude the molten alloy in the extrusion groove, thereby extruding the molten alloy in the cavity and further compacting the molten alloy in the cavity; Step four: Cool and solidify, then open the mold and eject the formed die-cast part; A push plate assembly and an extrusion plate assembly are provided in the moving mold of the mold. A push rod for ejecting the die-cast part in the moving mold is connected to the push plate assembly, and the extrusion rod is connected to the extrusion plate assembly. The push plate assembly and the extrusion plate assembly are linked together. In step three, the piston rod of the die-casting machine pushes the push plate assembly to drive the extrusion plate assembly forward, which in turn drives the extrusion rod forward to extrude the molten alloy in the extrusion groove. In step four, the piston rod of the die-casting machine continues to push the push plate assembly forward to drive the push rod forward, thereby ejecting the formed die-cast part. The linkage between the pusher assembly and the extrusion plate assembly is achieved as follows: the extrusion plate assembly is located behind the pusher assembly, and the pusher assembly and the extrusion plate assembly are connected by a resin opener / closer. A rubber pad is provided at the end of the push rod for cushioning, and a stop post is provided in the moving mold to limit the forward stroke of the extrusion plate assembly. In step three, the piston rod of the die-casting machine pushes the pusher assembly, and the pusher assembly drives the extrusion plate assembly forward through the resin opener / closer, thereby driving the extrusion rod forward to extrude the molten alloy in the extrusion groove. The push rod remains in place due to the cushioning effect of the rubber pad. In step four, the piston rod of the die-casting machine continues to push the pusher assembly, and the extrusion plate assembly stops moving forward due to the obstruction of the stop post. The resin opener / closer gradually disengages from the pusher assembly, and the pusher assembly pushes the push rod forward, thereby ejecting the formed die-cast part.

2. The high-vacuum die-casting extrusion composite process according to claim 1, characterized in that: After the molten alloy is injected, a set pressure is continuously applied to the molten alloy in the cavity through the injection port of the mold until step three is completed.

3. The high-vacuum die-casting extrusion composite process according to claim 1, characterized in that: In step two, during the process of injecting the molten alloy into the cavity, the die-casting machine continuously evacuates the cavity until the injection of the molten alloy is completed.

4. The high-vacuum die-casting extrusion composite process according to claim 1, characterized in that: The extrusion groove is located on the channel connecting the cavity and the vacuum channel.

5. The high-vacuum die-casting extrusion composite process according to claim 1, characterized in that: In step two, after evacuating the cavity once, the vacuum level inside the cavity is checked. If the vacuum level does not reach the set value, the cavity is evacuated again, and this process is repeated until the vacuum level reaches the set value.

6. The high-vacuum die-casting extrusion composite process according to claim 1, characterized in that: The push plate assembly includes a push plate and a push rod fixing plate. The push rod fixing plate is fixedly installed on the push plate in a superimposed manner. The push rod passes through the push rod fixing plate. The rubber pad is embedded in the push plate and rests on the head of the push rod.

7. The high-vacuum die-casting extrusion composite process according to claim 1, characterized in that: The extrusion plate assembly includes an extrusion plate and an extrusion rod fixing plate. The extrusion rod fixing plate is fixedly installed in the extrusion plate in a superimposed manner. The extrusion rod passes through the extrusion rod fixing plate, and the head of the extrusion rod is restricted by the extrusion plate.

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