Mold Steel Selection Checklist: P20 vs H13 vs S136 for Production Volume
Choosing mold steel by price alone often costs more later if the steel wears out before the production run is finished. This checklist lists what to review before selecting a steel grade for a tooling quote.
Mold steel selection depends on expected shot count, resin abrasiveness and cosmetic polish requirement, not only tooling budget.
Expected shot count and steel life
P20 suits shorter runs at lower tooling cost, while H13 or S136 hold up longer under high shot counts or demanding resins.
- Expected total shot count over the mold life.
- P20 typical life range versus H13 or S136.
- Plan if volume exceeds the original steel life estimate.
Resin abrasiveness and wear resistance
Glass-filled or mineral-filled resins wear gates and thin flow channels much faster than unfilled resin, which can justify a harder steel or local inserts.
- Glass fiber or mineral filler content in the resin.
- Wear risk at gates and thin flow channels.
- Whether a harder steel or wear insert is needed at high-wear points.
Cosmetic polish and corrosion resistance
S136 holds a high cosmetic polish and resists corrosion better in humid storage or with corrosive resins like flame-retardant or PVC grades.
- Target surface polish or texture grade.
- Corrosion risk from humid storage or corrosive resin additives.
- Cost difference between steel grades at the target volume.
Deciding on mold steel grade?
Send the expected shot count, resin type and cosmetic finish requirement before requesting a tooling quote.