Design of the body plastic mould under the car door panel

Design of the body plastic mould under the car door panel

Design of the body plastic mould under the car door panel

The lower body of the car door panel is an important part of the car interior parts. It is located on the inner side of the car door and has the front, rear, left and right points. It is usually two or four doors according to the car system. These parts are collectively called the door plate series. The door panels are divided into front, rear, left and right, but the front and rear door panels have different shapes and structures in different car designs. The conventional door panels are integral door panels and also have split door panels.
The difference between the integral type and the split type door panel is that the integral door panel plastic part is a whole, and the split door panel design divides the door panel into upper, middle and lower sections, which is very common in the design of automobile plastic parts, and the door panel mold case introduced in this chapter. It is a split door panel.

Design of the body plastic mould under the car door panel

1. Plastic parts appearance requirements and structural analysis
The material is PP+EPDM, and the shrinkage rate is generally 1.012. EPDM can improve the elasticity of the door panel, and the number of mold cavities is 1+1. The outer surface is textured, the plastic parts are appearance parts, and the surface requirements are high.
The dimensions of the plastic parts are: 1042.3*497.5*89.8mm. The characteristics of the plastic parts are as follows:
1) The appearance of the surface is required to be high, the appearance of the plastic part needs skin grain, the surface of the plastic part is not allowed to have spots, the gate mark, and it is not allowed to have shrinkage depression, weld line, flash edge and other defects.
2) The plastic parts are skin-grained parts, and the design of the plastic part appearance surface (A side) should be reasonable (generally at least 5 degrees).
3) The shape of the plastic parts is complex, the surface finish is high, and there are 12 undercuts on the inner side of the plastic parts.

2. Mold structure analysis
According to the structural characteristics of the body plastic parts under the door panel, the mold preferentially adopts the hot runner injection molding structure, and adopts a 10-point needle valve type sequence valve hot runner + cold runner + banana gate (commonly known as horn) into the glue. The inner side of the plastic part shown in Figure 1 has a total of 12 inverted buckles, all of which adopt a diagonal push block core-pulling structure.
The die has dimensions of 1780*1750*1342 (mm) and a total weight of about 18 tons. It is a large  injection mold.

3. Mold work process
The melt passes through the nozzle of the injection molding machine and enters the mold cavity through the hot nozzle 30. After the melt fills the cavity, after the pressure is maintained, cooled and solidified, after the rigidity is sufficient, the injection molding machine pulls the movable mold fixing plate 18 of the mold, and the mold is divided. The mold is opened at the profile PLI. After the mold is opened 500mm, the injection molding machine cylinder pushes the pusher fixing plate 19, the pusher fixing plate pushes the ejector pin 23, and the first push out 25mm, and the first launch is completed under the action of the fixed distance splitter 45.46.47. Then the cylinder continues to act and continues to push out 200mm, pushing all the pushers to push the molded parts away from the moving mold. After the plastic parts are taken out, the injection molding machine cylinder pulls the pusher and its fixing plate to be reset, and then the injection molding machine pushes the movable mold to close the mold, and the mold starts the next plastic injection moulding.

4. Mold strength and parting surface tube design
In the mold design, according to the size and structure of a plastic part to design the mold, the first thing that puzzles the designer is whether the mold strength is sufficient? The size of the tube surface of the parting surface. Is the position and strength reasonable? How to solve these problems? The first thing to consider when designing a mold is the mold strength and mold cost. A mold designed by a highly experienced designer and a general designer saves a lot of mold cost.

5. Die exhaust system design
In automotive mold design, the design of the exhaust system is quite important. If the exhaust design is unreasonable, it will seriously affect the quality of the plastic parts. There will be filling defects, trapped gas, mold release, etc., which will burn the product when it is severely trapped. The car door panel belongs to the interior parts, the appearance of the plastic parts is strict, and it is important to design the exhaust gas reasonably.

6. Results and discussion
The mold adopts the demoulding system of push rod + push tube + oblique push block + push block + cylinder and the temperature control system and secondary ejection system of "straight-flow water pipe + inclined water pipe + water well".

These are Design of the body plastic mould under the car door panel.

Design of the body plastic mould under the car door panel

Design of the body plastic mould under the car door panel

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