Manufacturing process flow----injection molding process flow
1. Preparation before molding
1. Analyze and inspect the quality of molding materials
According to the performance requirements of the plastic process, check its various performance indicators, such as water content, etc.
2. Preheating of materials
3. Cylinder cleaning
During the injection molding process, when the color and raw material are changed, the barrel needs to be cleaned, and the empty injection method is generally used for cleaning.
2. Injection molding process
1. Plasticizing
The process of heating and melting granular plastics in the barrel to form a viscous melt
2. Injection filling
The screw advances rapidly to inject the plastic melt into the cavity until the molten material fills the cavity.
3. Pressure holding and feeding
The melt shrinks due to cooling, but because the screw process continues to move forward slowly, the melt in the barrel continues to inject into the cavity to supplement
shrinkage needs.
4. Cooling after gate freezing
The plastic at the gate is completely frozen until the product is ejected from the cavity, and the plastic in the cavity still has
Changes in temperature, pressure, and volume. When the product is demolded, the pressure inside the mold cavity is not necessarily equal to the external pressure, and the mold cavity
The difference between the internal pressure and the external pressure is the residual stress. When the residual stress is positive, it is difficult to demould, and the product is easily scratched or damaged.
rupture. When it is a negative value, there are depressions on the surface of the product or vacuum bubbles inside the product.
3. Treatment after bottle cap molding
1. Recooling
2. Sterilization
(1 and 2): Conveyor belts are used, cooled by exhaust fans, and sterilized with ultraviolet rays.
3. Stand at room temperature for 24 hours:
Different parts of the cap shrink due to uneven plasticization or due to uneven crystal orientation and cooling of the plastic in the cavity
to other reasons. There is inevitably some internal stress inside the bottle cap. Therefore, after standing at room temperature for a period of time, it can eliminate
Internal stress, improve the performance of plastic parts.
4. Printing
5. Package and store
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