Why using slider on mould
slider is use for undercut part, part have hole at side and part that can't to produce by only using 2 plate mold or 3 plate mold. So must be slider to make a mold for this part.
Type of slider and manufacturing
Slider have 2 type it is using angular pin and use cam. To fabricate mold with slider is complicated and need more calculation.
component for this mold is use angular pin and locking block and in slider need make hole for angular pin
no need to use angular pin and no need drill on slider but need to use spring to go back at base.