How to Manage MIM Engineering Changes: Mold Modification vs New Mold

Quick Q: Can a MIM mold be modified if the design changes?

Yes — but the cost and feasibility depend on the change type. Adding material (steel welding + recutting) costs $500-3,000. Removing material (cutting more steel away) costs $1,000-5,000. Adding a new side action costs $3,000-8,000. Growing a dimension (making a feature larger) is cheap. Shrinking a dimension (making a feature smaller or removing it) may require a new cavity insert.


Engineering change cost and lead time by change type:
Change Type Feasibility Typical Cost Lead Time Method
Increase hole diameter Easy $200-500 2-3 days EDM or drill core pin larger
Decrease hole diameter Moderate $500-2,000 1-2 weeks Replace core pin with larger (makes hole smaller in sintered part)
Add new hole Moderate $1,000-3,000 1-2 weeks Add core pin; may need new ejector layout
Remove hole Difficult $1,000-3,000 1-2 weeks Plug existing core pin hole in mold
Change overall dimension (grow) Easy $500-3,000 1-2 weeks Weld cavity surface and recut (adds material)
Change overall dimension (shrink) Difficult $2,000-8,000 2-4 weeks Must remove steel — may need new cavity insert
Add side action / slide Very difficult $5,000-15,000 4-8 weeks Major mold rework — can approach new mold cost
Change gate location Moderate $1,000-4,000 1-2 weeks Weld old gate, machine new gate
Add surface texture Easy $500-2,000 1-2 weeks EDM texture cavity surface
Change material None (if compatible) $0 (if same shrink factor) Only need sintering process requalification
When a new mold is cheaper than modifying:
  • If more than 3 features need change
  • If the overall part envelope changes by more than 5%
  • If a new side action or core pull is needed
  • If the cavity steel has been through multiple weld-repair cycles already
Change management process:
  1. Requestor submits Engineering Change Order (ECO) with drawing change marked up
  2. MIM manufacturer assesses feasibility and provides cost/lead time estimate
  3. ECO approved with budget
  4. Mold modification performed
  5. First article from modified tool fully inspected
  6. PPAP delta submission (only changed dimensions requalified)

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Contact: Cindy