The quality of automotive lighting is very important for driving safety. Therefore, the laws and regulations of all countries in the world today have strict requirements for automotive lighting. The design of lamps and lanterns not only meets the safety requirements of regulations, but also meets the requirements of some other aspects, such as The appearance should be integrated with the appearance of the entire car. It is beautiful and practical. It meets the requirements of aerodynamics and makes the driver and passengers comfortable and convenient. Therefore, the design technology of car lights changes with the development of the automobile industry.
Lamp material and process characteristics
The lamp is generally composed of a base and a lamp housing. The material of the base is usually a thermosetting material-BMC (bulk molding compound), and the lamp housing can be processed by materials such as PMMA, PP, ABS, and is usually two-color or three-color. In the production process of two-color lights, special attention should be paid to the injection part of a two-color injection molding machine. The center distance between the two screws should correspond to the center distance between two-color molds.
There are also the following important points that need to be strengthened:
1, the impact of the stability of the lamp forming elements
Control unit response: Long switching point, noise interference, unstable command output, unstable temperature;
Noise of hydraulic system: pressure instability, valve positioning quality, hysteresis, tubing damping change;
Differences in mechanical systems: internal leakage in the oil seal, damping, friction difference, screw check valve positioning, check effect;
Uneven plasticization: differences in plasticity;
Mold temperature control.
2, The design of the special plastic pipe assembly for car tail light
Screw idling does not feed;
The torque required by the screw is too large to rotate;
Plastics are not completely melted;
Screw metering instability;
Uneven mixing of plastics;
Low-temperature molding plastic easy temperature rise;
There are air bubbles in the molded product;
Easy to spit black and yellow inside the molded product;
The screw is easily corroded, wears, and has a short service life.
3, the main design focus of screw material group
The plastic plastic screw feed pipe group is the heart component of the injection molding machine. It is responsible for the transportation, melting, mixing and metering of plastic raw materials. Therefore, the plastic plastic screw is closely related to the quality of molded products.
The main purpose of the modified plastic screw is to:
Improve shear mixing;
Mix evenly;
Improve plasticizing ability;
Make sure melt temperature uniformity.
4, taillight special screw design focus
L/D ratio: 21~23;
The surface roughness must be extremely smooth to avoid accumulation of material;
Increase plating thickness and corrosion resistance;
Compression ratio: 2.3, feed section: about 50%, compression section: about 30%, metering section: about 20%.