Pressure Setting During Mold Open and Close

The molding machine does it’s best to achieve the set mold open and close speed as long as there is enough pressure available.


What is the pressure and speed relation for clamp open and close? How can I make sure that I have enough pressure to satisfy the set speed?


During clamp movement, the molding machine adjusts the pressure (or power when using electric machines) to the clamp in an attempt to achieve the desired speed. If adequate pressure is not available, the machine will not be able to achieve the desired open or close speed because the movement will be pressure limited… This will result in inconsistent clamp movements and part removal times.

It is easy to determine whether you are using enough pressure 1) Time the current part removal time. 2) increase the pressure and time the part removal time. If your part removal time decreases with a higher pressure (2), then you had inadequate pressure.

Additional Thoughts:

If you want to determine the optimum pressure: 1) Use the steps above to verify you are not pressure limited 2) incrementally reduce the pressures to determine the minimum pressure necessary to maintain your part removal time 3) once the minimum is determined, add 10% to each pressure to compensate for normal variation. These steps will ensure you have adequate pressure to maintain cycle time, but not excessive pressure… this will reduce the amount of mold and machine damage which might occur in the case of complications.


The above discussion does not include mold protect. Mold protect intentionally use a low-pressure, pressure limited clamp movement to protect the mold during the final stages of mold closing.

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