AUTOMOLD3D · BLOG
How to Choose a Parting Line for a Two-Part Mold
A well-chosen parting line lets both mold halves release cleanly while keeping seams away from critical detail.
Follow the model’s widest profile and identify any undercuts that would lock the part into one half. The parting line often needs to move around detail rather than follow a perfectly flat horizontal plane.
Keep the line on a less visible surface when appearance matters, but do not trade release safety for seam placement. Broad split faces also give registration pins and alignment features more dependable material.
Preview how each half opens, then inspect the pour path and venting strategy separately. A good parting line solves release; it does not automatically solve every casting-flow issue.