Injection mold production, often have a lot of factors will affect the quality of the product, to sum up basically has the following four points:
1). Plastic materials
The complexity of the plastic material performance determines the complexity of the injection molding process.And the performance of the plastic material on the basis of different varieties, different grades, different manufacturers, and even different and different batch.May lead to different performance parameters to control the molding results were completely different.
2.) injection temperature
The melt into the cooling of the mold cavity, the heat loss by heat conduction.At the same time, due to the shearing action to generate heat, the heat conduction of heat loss of low quantity of heat, may also be less, mainly depends on injection molding conditions.The melt viscosity with temperature and lower.In this way, the higher the temperature, injection melt viscosity is lower, the smaller the filling pressure.At the same time, injection temperature are limited to the thermal degradation temperature and decomposition temperature.
3). The mold temperature
The lower mold temperature, the faster the rate of heat loss by heat conduction, the melt temperature is lower, the more illiquid.When using low injection rate, this phenomenon is especially obvious.
4.) injection time
Injection time on the influence of the injection molding process is shown in three aspects:
(1) shorten the injection time, melt in the shear strain rate will also increase, in order to full of cavity need a higher injection pressure.
(2) shorten the injection time, melt of shear strain rate increase, due to the shear thinned characteristics of plastic melt, melt viscosity, in order to full of cavity injection pressure is needed to reduce.
(3) injection time was shortened, and the melt of shear strain rate increases, the greater the shear heat, less heat loss by conduction of heat at the same time, therefore, the melt temperature is high, the lower the viscosity, in order to full of cavity injection pressure is needed to reduce.Outcome of combined action of the above three conditions, make full of cavity injection pressure needed to present "U" shape curve.That is to say, there is a injection time, injection pressure required for minimum at this time.
Plastic technology, affect the quality of injection mold are four key points
2016 11/03