Hot runner mold design key points
Hot runner mould refers to a mould that heats the part of the runner so that the plastic in the runner is always in a molten state.For the mold with more cavity number or single cavity mold with multi-gate gate, the hot-runner mold is generally designed.The biggest characteristic of hot runner mould is to save raw materials.Shorten the forming period;Improve product quality;Cost reduction;Easy to implement automatic production.At the same time, to a certain extent, it overcomes the hollows and shrinkage holes of plastic parts caused by insufficient plastic filling.But the hot runner mould manufacturing cost is high, the system is more complex, the debugging is difficult.
Design points of hot runner mould:
1. In the heat flow channel mold, all corners in the flow channel should be rounded and smooth, and no dead Angle of material retardation is allowed.
2. Heat flow channel plate, cavity plate and fixed template must have good thermal insulation performance.Insulation materials generally used asbestos board, air, etc.The hot runner plate and other parts of the mould should be supported as little as possible and the force should be balanced.
3. The temperature of the heat flow channel plate should be even, and the heater should be symmetrical, so as to ensure that the heating power and heating position of each channel are even.Heat storage of heat flow channel plate should be as small as possible to save energy.
4. The heat flow channel plate and the nozzle with two edges shall be controlled by temperature respectively, and the multi-gate mold can be controlled by zone.
5. The cavity of the heat flow channel mold should have good cooling performance, so as to quickly take away the heat transferred from the plastic parts and the secondary nozzles, so as to obtain the high-speed forming effect.
6, the secondary nozzle head and gate of difference in temperature big disparity is the key to the hot runner mold, is usually as far as possible, reduce the secondary nozzle head and temperature difference between heat flow but, increase the temperature difference between the nozzle and mold.