Injection molding is a process to obtain plastic molded products stably and quickly.
The molding cycle of filling and cooling is determined by the type and temperature of the resin.
To increase the number of resin molded products per molding cycle, multiple molds with the same shape can be used (multi-cavity molding).
The number of resin molded products per molding cycle can be increased by incorporating multiple molds of the same shape (multiple molding).
When multiple product shapes are incorporated into a mold, the way they are arranged and the shape of the runners must be considered.
If the resin filling is not balanced, it will cause defects to occur.
When products are placed, if the runners are of different lengths, the filling balance is disrupted, resulting in shorts and other problems. If the problem can be solved by using a setup generally referred to as an equal-length runner, the problem cannot be completely eliminated.
This is because the resin tries to flow along the shortest route (smallest pressure loss) like a marathon runner.
Therefore, the larger the diameter of the runner, the more unbalanced it becomes.
★To set up a simultaneous fill runner (when flow analysis is performed)
It can be said that the thickness and length of the runner must be intentionally changed.
In this regard, prior flow analysis using CAE will enable a smooth start-up of mass production.
★Simultaneous filling runner design (when flow analysis is not performed)
This method is useful because it can be applied in cases where flow analysis software is not available or for thermosetting resins that are difficult to analyze.
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