Design guide hub
All DFM topics on one route.
Design guide hubDFM
Undercuts: Injection Molding Design Rules
Undercuts force side actions, lifters, or assembly tricks. They belong on the drawing early.
DFM
Eliminate undercuts when possible
Rules NetProto DFM review checks against before steel is ordered.
Each side action adds mold cost and maintenance.
Snap fits can sometimes replace external undercuts with controlled deflection.
CAD checklist
Send this with your upload
Missing DFM inputs delay qualified quotes.
External undercut map
Side action acceptance if needed
Draw direction locked
Related rules
Design guide
Jump to sibling rules before you freeze CAD.
DFM article
Long form engineer guide.
DFM articleWall thickness
Design rules for wall thickness.
Wall thicknessDraft angle
Design rules for draft angle.
Draft angleRib design
Design rules for rib design.
Rib designFAQ
Common questions
Can NetProto mold undercuts?
Programs quote side actions when DFM accepts the mold complexity.
Next step
Upload CAD for DFM-aware quoting
One hardened steel tool quote with piece price on the same upload.