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How to achieve consistent mould filling

Update:03 Aug 2018
Summary:

During the test mode, you need to pay attention to the […]

During the test mode, you need to pay attention to the following points:

1. In order to reach the end of the fill, the plastic requires an overall pressure of 2200 psi.

2. In order to reach the middle part of the product, plastic almost requires an overall pressure of 2200 psi.

Based on the above two points, the process is limited by pressure.

The plastic requires a pressure of 1379–983 = 396 psi to reach the end of the tertiary shunt from the end of the secondary shunt. In order to flow through the gate, plastic requires a pressure of 1897–1379 = 518 psi.

Therefore, the three-stage runner and gate appear to have a relatively large pressure drop, so the three-stage runner and gate should be enlarged. This will reduce the final pressure at the end of the filling to 1901 psi. The process is no longer limited by pressure. Ensuring adequate injection pressure will help achieve consistent mould filling. In the mould certification process, the study of pressure drop is one of the most important steps.

Finally, remember the rule of thumb: the maximum injection pressure required should not exceed 80% of the maximum pressure that can be obtained by the injection moulding machine.

Above the value - 80%, should be lower for thicker products that require higher holding pressure. To avoid sudden increases in pressure between different parts, the transition should be as smooth as possible.

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