A thermal expansion low-pressure injection molding system for thin-walled products

Abstract

The present invention belongs to the technical field of injection molding system, and provides a thin-walled product thermal expansion low-pressure injection molding system, including an upper mold cavity and a lower mold cavity, the product is located between the upper mold cavity and the lower mold cavity, a heating rod and a cooling pipe are arranged between the upper mold cavity and the lower mold cavity, and an aluminum expansion block is also arranged between the upper mold cavity and the lower mold cavity, the heating rod heats the aluminum expansion block to increase its volume and increase the distance between the mold cavities, and the cooling pipe cools the aluminum expansion block to reduce its volume. The advantage of the present invention is that when the product is injection-molded and filled, the higher expansion performance of the aluminum block is used to increase the product thickness, and when the injection molding filling is completed and the pressure is maintained, the aluminum block is cooled to return the product thickness to normal thickness, thereby achieving the purpose of low-pressure injection molding.

Description

Technical Field

[0001] The invention belongs to the technical field of injection molding systems, and in particular relates to a thermal expansion low-pressure injection molding system for thin-wall products. Background Art

[0002] With the continuous improvement of automobile emission standards, lightweight design of automobiles is an important means to meet emission standards. This not only saves energy and reduces emissions, but also reduces automobile costs. For electric vehicles, it can also increase driving mileage. When the wall thickness of the product is reduced to a certain extent by using traditional product lightweight methods, the phenomenon of extreme injection molding process will occur, which will cause injection molding difficulties. The injection pressure is too high, the internal stress of the product increases, the deformation wing is large, and the product is prone to flash. Ultra-high pressure not only damages the product, but also is not good for the mold. In some places where the mold is weak, long-term high pressure will reduce the fatigue strength of the steel and cause cracking damage. The low-pressure injection molding method in the current industry has a complex structure and is not conducive to mass production and later maintenance. There are two existing low-pressure injection molding methods. One is to use the latest injection molding machine with low-pressure mold clamping function, and the other is to add a secondary ejector mechanism to the mold part. The ejector mechanism is in the ejection state (cavity thickening) before mold clamping filling. After the injection molding filling is completed, the ejector mechanism retreats and the cavity thickness returns to the thickness of the product design. Among the above two methods, the first one is a new electric injection molding machine, which is more expensive. For general workshops, most of the existing injection molding machines are still hydraulic injection molding machines. These technologies can be used as a solution for upgrading the functions of injection molding machines. The second method requires adding an ejector mechanism in the mold. This ejector mechanism is a movable part, but in order to prevent flash during injection molding, the ejector mechanism has no ejection draft angle and is a straight ejector. In this way, during mass production, it is easy to damage the surface and cause ejector jamming and other defects. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a thin-walled product thermal expansion low-pressure injection molding system in response to the current status of the prior art, which solves the problem of difficulty in filling thin-walled parts. By slightly adjusting the mold structure, an ordinary injection molding machine can achieve the function of low-pressure injection molding.

[0004] The technical solution adopted by the present invention to solve the above-mentioned technical problems is: a thin-walled product thermal expansion low-pressure injection molding system, characterized in that it includes an upper mold cavity and a lower mold cavity, the product is located between the upper mold cavity and the lower mold cavity, a heating rod and a cooling pipe are arranged between the upper mold cavity and the lower mold cavity, and an aluminum expansion block capable of adjusting the distance between the upper mold cavity and the lower mold cavity is also arranged between the upper mold cavity and the lower mold cavity, the heating rod heats the aluminum expansion block to increase its volume and increase the distance between the mold cavities, and the cooling pipe cools the aluminum expansion block to reduce its volume and reduce the distance between the upper mold cavity and the lower mold cavity.

[0005] In the above-mentioned thin-wall product thermal expansion low-pressure injection molding system, the upper and lower surfaces of the aluminum expansion block are provided with bakelite insulation layers, and the aluminum expansion block is provided with a cooling water channel.

[0006] In the above-mentioned thin-wall product thermal expansion low-pressure injection molding system, when the aluminum expansion block is heated, the distance between the upper mold cavity and the lower mold cavity changes from 0 mm to 0.3.

[0007] In the above-mentioned thin-wall product thermal expansion low-pressure injection molding system, when the aluminum expansion block is cooled, the distance between the upper mold cavity and the lower mold cavity changes from 0.3 mm to 0 mm.

[0008] In the above-mentioned thin-wall product thermal expansion low-pressure injection molding system, the aluminum expansion blocks are arranged on the four edges of the upper mold cavity and the lower mold cavity, and are symmetrically distributed left and right and up and down.

[0009] Compared with the prior art, the advantage of the present invention is that during product injection molding and filling, the higher expansion performance of the aluminum block is used to increase the product thickness. When the injection molding and filling are completed and the pressure is maintained, the aluminum block is cooled to make the product thickness return to normal thickness, thereby achieving the purpose of low-pressure injection molding. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic diagram of the structure of the thin-walled product thermal expansion low-pressure injection molding system after heating;

[0011] Figure 2 It is a schematic diagram of the structure of the low-pressure injection molding system for thermal expansion of thin-walled products after cooling;

[0012] Figure 3 It is a structural schematic diagram of an aluminum expansion block. DETAILED DESCRIPTION

[0013] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0014] In the figure, the upper mold cavity 1; the lower mold cavity 2; the product 3; the heating rod 4; the cooling pipe 5; the aluminum expansion block 6; the bakelite insulation layer 7; and the cooling water channel 8.

[0015] like Figure 1 , Figure 2 as well as Figure 3As shown, the thin-walled product thermal expansion low-pressure injection molding system includes an upper mold cavity 1 and a lower mold cavity 2, and the product 3 is located between the upper mold cavity 1 and the lower mold cavity 2. A heating rod 4 and a cooling pipe 5 are arranged between the upper mold cavity 1 and the lower mold cavity 2. An aluminum expansion block 6 capable of adjusting the distance between the upper mold cavity 1 and the lower mold cavity 2 is also arranged between the upper mold cavity 1 and the lower mold cavity 2. Here, the aluminum expansion block 6 is arranged on the edges of the upper mold cavity 1 and the lower mold cavity 2, and is symmetrically distributed left and right and up and down. At the same time, the upper and lower surfaces of the aluminum expansion block 6 have a bakelite insulation layer 7, and the aluminum expansion block 6 has a cooling water channel 8. The aluminum expansion block 6 is heated by transferring heat to the bakelite insulation layer 7 through the heating rod 4, and is cooled by connecting the cooling pipe 5 to the cooling water channel 8 during cooling. This is the greatest innovation of this patent. Due to the higher expansion performance of the aluminum block, the distance between the upper mold cavity 1 and the lower mold cavity 2 can be adjusted.

[0016] Specifically, before the mold is closed, the mold status is as follows:

[0017] At the beginning of injection molding, the aluminum expansion block 6 placed on the parting surface is heated, and the temperature control system heats the aluminum expansion block 6 through the heating rod and the heating rod 4 to increase its volume and increase the distance between the mold cavities. When the aluminum expansion block 6 is heated, the distance between the upper mold cavity 1 and the lower mold cavity 2 changes from 0mm to 0.3, which is similar to the increase in the thickness of the product 3 to facilitate filling. After filling, the temperature control system controls the cooling pipe 5 to cool the aluminum expansion block 6 to reduce its volume and reduce the distance between the upper mold cavity 1 and the lower mold cavity 2. When the aluminum expansion block 6 is cooled, the distance between the upper mold cavity 1 and the lower mold cavity 2 changes from 0.3mm to 0mm, and the cavity thickness returns to the designed thickness of the product 3, which solves the problem of difficulty in filling thin-walled parts. Through slight adjustments to the mold structure, ordinary injection molding machines can realize the function of low-pressure injection molding, reduce product weight, achieve lightweight parts, and enhance the company's competitiveness.

[0018] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner without departing from the scope defined by the spirit of the present invention.

Claims

1. A thin-wall product thermal expansion low-pressure injection molding system, characterized in that: It includes an upper mold cavity and a lower mold cavity, and the product is located between the upper mold cavity and the lower mold cavity. A heating rod and a cooling pipe are arranged between the upper mold cavity and the lower mold cavity. An aluminum expansion block capable of adjusting the distance between the upper mold cavity and the lower mold cavity is also arranged between the upper mold cavity and the lower mold cavity. The heating rod heats the aluminum expansion block to increase its volume and increase the distance between the mold cavities. The cooling pipe cools the aluminum expansion block to reduce its volume and reduce the distance between the upper mold cavity and the lower mold cavity.

2. A thin-wall product thermal expansion low-pressure injection molding system according to claim 1, characterized in that: The upper and lower surfaces of the aluminum expansion block are provided with bakelite heat insulation layers, and the aluminum expansion block is provided with a cooling water channel.

3. A thin-wall product thermal expansion low-pressure injection molding system according to claim 2, characterized in that: When the aluminum expansion block is heated, the distance between the upper mold cavity and the lower mold cavity changes from 0 mm to 0.3 mm.

4. A thin-wall product thermal expansion low-pressure injection molding system according to claim 2, characterized in that: When the aluminum expansion block is cooled, the distance between the upper mold cavity and the lower mold cavity changes from 0.3 mm to 0 mm.

5. A thin-wall product thermal expansion low-pressure injection molding system according to claim 2, characterized in that: The aluminum expansion blocks are arranged on the edges of the upper mold cavity and the lower mold cavity, and are symmetrically distributed left and right and up and down.

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