Two shot single tool
- Bond line controlled in mold
- Higher tooling and process development
- Justified when materials must share one continuous part
DFM
Two Shot Part Design: Injection Molding Design Rules
Two shot design needs bond surfaces, shutoffs, and clear scope versus assembling two parts.
DFM
Two shot part design starts with bond surfaces and shutoffs
Multi material programs need mechanical interlock and clean substrate geometry.
The first shot substrate must support the second shot without flash across bond lines.
Shutoff steel between materials is sensitive to wear and maintenance at volume.
Programs that do not need two materials on one part should not pay two shot tooling complexity.
DFM
Quote this rule with your CAD upload
NetProto DFM review flags these geometry patterns before steel is ordered.
- Call out draw direction and cosmetic faces on the model.
- Note resin family even when the grade is not final.
- Tighten tolerances only on mating features that need them.
Program
Two shot on one tool versus assembly of two molded parts
NetProto production focus is hardened steel tooling for qualified programs. Confirm scope on quote.
Two separate molded parts assembled
- Simpler single material molds
- Assembly labor or snaps added
- Often enough for color break or soft touch pads
Related rules
Design guide
Jump to sibling rules before you freeze CAD.
Design guide hub
All DFM topics on one route.
Design guide hubDFM article
Long form engineer guide.
DFM articleOvermolding
Soft touch and insert context.
OvermoldingParting line
Shutoffs between materials.
Parting linePlastic injection molding
Production quoting path.
Plastic injection moldingVisual reference
Molding context for this rule
Images from the Forge media library illustrate typical programs.
Injection molded part design review on CAD
Injection molded part design review on CAD
Plastic housing with ribs and bosses
Plastic housing with ribs and bosses
Engineer measuring molded component
Engineer measuring molded component
FAQ
Two shot questions
Does NetProto quote every two shot program?
Upload CAD and material intent. Scope is confirmed on qualified quotes.
Can two shot be simulated in DFM?
Bond surfaces and shutoffs are reviewed on CAD before steel.
Is overmolding the same as two shot?
Related family. Overmolding often uses insert or substrate programs. Confirm terms on RFQ.
Next step
Upload two shot CAD with material intent
Show bond surfaces and which regions are shot one versus shot two.