What is a vent in the mold, what problems are prevented by the presence of a vent, and what parameters control its size?
What will be an ideal response?
The vent is a small opening from each cavity that allows air to escape as the resin enters. If the vent were not present, hot air could be trapped and burn the resin as it enters, thus causing a discoloration. The air could also build to such a pressure that the resin may be prevented from completely filling the mold. The vents should be large enough that the air will freely leave the cavity with the injection of the resin, but not so large that the resin will flow through them.
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