When you run a Cool analysis, you can specify whether to set the injection + packing + cooling time manually (specified), or as automatic.
The following topic describes the differences between a Cool analysis with a manual or automatic time set.
A specified analysis is used when you want to examine temperature distributions for a given cavity, mold, and processing conditions. The result is the mold temperature distribution given by the fixed variables of melt temperature, coolant selection, and coolant flow rates.
It is also the analysis required when a design is being taken through to Warp analysis, as plastic processing conditions and cycle time are generally fixed by the molding requirements.
Cooling of the plastic occurs from the commencement of the filling phase. However, the "Injection + packing + cooling time" value specified is the time required to cool the part sufficiently for ejection. The material at the center section of the part wall reaches its transition temperature and becomes solid during this time. The material at the center section of the part wall reaches its transition temperature and becomes solid during this time .
An automatic analysis adjusts processing parameters to optimize the cooling time required to achieve a target average mold temperature specified in the Process Settings Wizard and the specified percentage freeze level in the plastic part.
The automatic analysis calculates the cycle time based on two parameters:
Because of these assumptions, the automatic analysis should not be run unless the cooling system has been optimized, and the average cavity temperature is less than the target mold temperature.
The target mold temperature is the Mold surface temperature entered in the Process Settings wizard.
The percentage plastic frozen is the ratio of the volume of plastic that is frozen in the part to the volume of the part. During an automatic analysis, a plastic state of freeze target is required. The default value is 100 percent frozen. If this yields cooling times that are too long, for example, where a thick section is present, reduce the Frozen percentage at ejection value. This will reduce the calculated cooling time, whilst maintaining adequate freezing in the critical areas of the cavity.