The mold costs can be lowest if the center line of the thread lies in the
parting plane of the mold. An expensive external unscrewing device is not
necessary in that case. A parting line will however be visible on the surface
of the part.
If this is not acceptable, or if the center line of the thread cannot be
located in the parting plane, for instance because the center line is in the
mold opening direction, the part must be stripped from the mold, or an
unscrewing device must be used.
Mold without unscrewing device