What should be paid attention to in the design of hot runner mold structure?
The following problems should be paid attention to in the design of hot runner mold structure:
1) the gate of the hot runner mold is required to be opened at the time of injection and closed after the injection, so as to ensure no leakage.For this general approach is to precise temperature control of gate parts, such as set in the end of the valve, a small heater in a molding cycle, smaller heater on and off of the transform, control the gate of the seal.There is also a mechanical method to seal the gate, such as the spring in the valve body, and the injection pressure to control the opening and closing of the gate;Use hydraulic system to control valve in gate section.
2) when designing the hot runner mold, due to the increase of the runner plate, it is necessary to pay attention to the relationship between the mold thickness and the minimum distance of the injection machine.
3) the adiabatic between the channel plate and the fixed mold base plate and the fixed template is very important. The air insulation method is generally used, and there is a gap between 3 ~ 8mm between the plate and the plate.
4) the spacing area should be as small as possible.And it is set in the position that the channel plate deformation is not caused when the clamping force and injection pressure are subjected.
5) on the opposite side of the main channel and the secondary nozzle, the bearing parts must be set.
6) the gap components and the bearing parts should be used in materials with low thermal conductivity, such as stainless steel.
7) flow channel of the diameter of the decision, to consider the amount of plastic injection, such as excessive flow injection quantity is small, the plastic in the heating zone time growth, cause burning and molding defects such as uneven, flow lines.Small flow leads to pressure loss and increased injection pressure.