the third principle for deciding on the parting line is to keep the plastic part on the side of moving half of it’s mold,
In general, the fastening force exerted by the plastic part shrinkage on the core is greater than the one on the cavity, thus the plastic part remains on the core and with the core, separate from the moving half.while opening the mold, it is easier to eject the part, if it stays with the moving half which has an ejection mechanism.