The headlight housing is part of the headlight base and wiring harness before installation. It belongs to the internal functional components, and the external components have many assembly dimensions. The lamp holder has high precision and the installation harness has a large size.
The lamp mold is part of the headlight lamp cover part, the material is PP+TD20, wherein PP (polypropylene) is the base of the lampshade, and TD20 means adding 20% talcum powder to the material to improve the rigidity of the lampshade. This part is not the appearance part, but the internal function. The average wall thickness of the plastic parts is 3.00 mm, and the maximum size of the plastic parts is 320.9*228.4*344.3 mm. The characteristics of plastic parts are as follows:
1. The plastic part is an internal functional part, and the lamp cap hole and the back cover hole have many assembly dimensions and high precision.
2. No spot is allowed on the surface of plastic parts. Defects such as shrinkage holes, weld marks and burrs are not allowed.
3. The shape of the plastic parts is complicated and the parting surface is complicated.
4. In addition to the asymmetrical aperture of the lamp head, the left and right lamp housings are asymmetrical.
5. There are two inverted buckles on the outside of the plastic parts, and the parting surface is complicated.
Since the lamp mold is a large mold, the parting surface is complicated, and the mold part and the template adopt an integrated structure, that is, the fixed mold a plate is a fixed mold forming part, and the moving mold B is a moving mold forming part. The structure has the advantages of compact structure, high strength, good rigidity, small mold volume, and avoids complicated procedures such as opening a frame, arranging a frame, and manufacturing a groove.
Since the plastic parts are PP+TD30 and no parts are present, the fixed and movable mold steels can be P20 or 718.
Since the push mechanism is on the movable mold side, the plastic parts must be held on the movable mold side after the mold is opened. Due to the complex shape of the plastic parts, the plastic parts may stick to the fixed mold after the mold is opened. Therefore, when designing a lamp mold, it is necessary to prevent the occurrence of a fixed mold phenomenon. The specific measure is to design the ribs and the reverse buckle type on the side cylinder of the movable mold to the area where the plastic parts are strongly stressed. If it is still fixed, design a buckle on the push rod to keep the molded part on the side of the movable mold.
Pay attention to the design of the lamp holder during design. The left and right of the lamp hole is a translational relationship, not a mirror relationship. This is one of the mistakes that lamp mold designers can easily make. Pay attention to the dimensional accuracy of the lamp cap hole. The ventilation angle must be within 0.5°, otherwise it will affect the installation of the lamp holder. The lamp housing plastic part has a plurality of ribs, and the boss has a plurality of columns. There are many fixed, movable molds that are inserted into the injection mold and push tube. Fixed and mobile mold inserts should be positioned with a mushroom head to tilt. Screw as far as possible from the front and copper at the bond.
In other respects, the design of the injection molded part should pay attention to the insertion angle. In the design of automobile molds, in order to improve the service life of the mold and avoid the insertion position of plastic parts, all the insertion positions are designed to be more than 7 degrees.
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