Do you know any key points that will affect the quality of the injection mold?
You know what?In fact, many factors will affect the quality of the injection mold in the production process. Next, Shanghai pujoni summarized four major problems for you. Let's get to know them together.
1). Plastic materials
The complexity of plastic material determines the complexity of injection molding process.And the performance of plastic material is different because breed is different, brand is different, manufacturer is different, even batch is different and different big difference.Different performance parameters may lead to different molding results.
2). Injection temperature
The melt flows into the cooling cavity and loses heat due to heat conduction.At the same time, heat is generated due to shear action, which may be more or less than heat loss, mainly depending on injection conditions.The viscosity of melt decreases with increasing temperature.Thus, the higher the injection temperature, the lower the melt viscosity, the lower the required filling pressure.At the same time, the injection temperature is also limited by the temperature of thermal degradation and decomposition.
3). Mold temperature
The lower the mold temperature, the faster the heat loss due to heat conduction, the lower the melt temperature, and the worse the fluidity.This is especially true when low injection rates are used.
4). Infusion time
The impact of injection time on the injection molding process is shown in three aspects:
(1) to shorten the injection time, the shear strain rate in the melt will also be increased, and the injection pressure required to fill the mold cavity will also be increased.
(2) the injection time is shortened and the shear strain rate in the melt is increased. Due to the shear thinning characteristics of the plastic melt, the melt viscosity is reduced, and the injection pressure required for filling the mold cavity is also reduced.
(3) shorten the injection time, increase the shear strain rate in the melt, the greater the shear heating, and the less the heat lost due to thermal conduction. Therefore, the higher the temperature of the melt, the lower the viscosity, and the lower the injection pressure required to fill the mold cavity.The combined effect of the above three conditions makes the curve of injection pressure required to fill the cavity appear "U" shape.In other words, there is an injection time when the injection pressure required is minimal.