The Hold pressure result shows the maximum pressure in each area, calculated during the packing phase (from the end of fill).
A big variation in the maximum hold pressure indicates that pressure is not transferred to the extremities of the cavity during the packing phase.
This result is generated from Pack analyses using Midplane or Dual Domain analysis technologies, and Overmolding analyses.
Differences in hold pressure may be caused by the following:
- a poorly designed part with thin sections that freeze early
- an inappropriate gate size, shape or position
- not enough packing pressure
- not packing the cavity for a long enough period
When areas freeze with different pressures, differential shrinkage effects occur, contributing to increased warpage.
Using this result
Use the Hold pressure result to ensure that packing pressure applied at the injection locations is being transmitted throughout the cavity. A uniform pressure distribution will result in even packing as the part freezes, resulting in less warpage. The greater the pressure variations, the greater the warpage is likely to be.
Note: Not all values displayed in the Hold pressure result occur at the same time, maximum pressure for each area can occur at different times during the packing phrase.
To reduce variation in the
Hold pressure result, you can do the following:
- increase the packing pressure
- increase the packing time
- change the gate size
- change the packing profile
Things to look for
- Isolated areas of low pressure surrounded by areas of high pressure may occur where thick regions of the part are being fed from thin areas of the part. You may need to change the gate location, or part geometry.
- A uniform drop in the pressure as the flow front approaches the last areas to fill may indicate there is a problem with the gate size or packing profile. This usually happens when the gate is too small and freezes too early, or when packing pressure has not been applied for a long enough period. Increase the gate size or change the packing profile.