Plastic light guide plates are used in almost all liquid crystal displays.
The materials used in the light guide plate are basically PMMA or PC plastic with good transparency.
Injection molding machines are available in sizes from 55T to 300T:
- Medium and low-end products use hydraulic driven mechanical injection molding machines.
- Medium and high-end products use vertical injection molding machine or electro-hydraulic composite injection molding machine.
- For high-end products, an all-electric motor or an injection molding machine with injection compression function is used.
The light guide plate is a high-precision optical product, which requires the finished product network to be complete and not shrink and deformed as a whole; There are no black and yellow spots, no crystal spots, no impurities on the surface of the product, and the overall finish and transmittance are good.
Based on the quality requirements, for example, the main processing process requirements of the light guide plate of the mobile phone are as follows:
- Its molding can be 120T rotary vertical injection molding machine clamping force, injection molding should be sufficient, template parallelism should be high, to ensure that the product does not have flash, uniform thickness.
- The equipment is required to be injected stably and measured accurately.
- The injection volume of the equipment does not have to be too large, too large is easy to make the melt yellow and discolored. In order to prevent the yellowing of plastics and the problem of black and yellow spots, the finish of plasticized components is required.
- The equipment is required to have high injection pressure and fast injection speed. Due to the poor fluidity of PMMA and PC plastic melts, especially when processing thin-walled light guide plates, large injection pressure and large injection speed are required.
- Due to the large viscosity of the melt, the screw is required to have a large rotational torque. At the same time, the screw is required to have strong torsion resistance in structural design.
- The mold design should meet the requirements of smooth filling and smooth demoulding, and the mold processing accuracy should be high and there should be an accurate exhaust groove.
