Because many molds are built directly off a 3-D surface file there may not be clear dimensions, especially if the schedule is compressed. Always make sure you let consultants know of dimensional risks.

All parties look bad if parts don’t look or function perfectly out of the mold. If you think a critical dimensional specification is missing, ask for it. Also, there are varying practices for tolerance clearance between parts. Some consultants build in all tolerance to parts, so moldmakers are not expected to modify the geometry. Others design line-to-line and expect the moldmaker and/or molder to figure out the tolerance. Avoid unwanted surprises by knowing exactly the practices of design consultants.