A thorough MIM supplier audit reveals more about capability than any brochure or sales presentation. Here is a 30-point checklist organized by area.
1. Quality System (6 points):| Check Item | What to Verify |
|---|---|
| ISO 9001 / IATF 16949 certificate | Current, in-scope for MIM, surveillance audit up to date |
| PPAP documentation | Last 3 PPAP submissions — completeness and customer approval |
| Non-conformance handling | Recent NCR records — corrective actions and closure timeliness |
| Calibration system | CMM and gauge calibration records — NIST traceable |
| Internal audit records | Last 12 months of internal audits and findings |
| Customer complaints log | Last 12 months — trends and preventive actions |
| Check Item | What to Verify |
|---|---|
| Powder receiving inspection | PSD, oxygen, chemistry tested on every lot (not just CoA review) |
| Feedstock compounding | MFI verification per batch — records showing ±5% control |
| Regrind control | Regrind ratio documented and verified |
| Batch traceability | Can trace a finished part to its powder lot number |
| Material certifications | CoA files for last 12 months — all lots accounted for |
Shot weight SPC records, mold maintenance schedule, machine calibration, operator training records.
4. Debinding (3 points):Weight loss verification records, furnace temperature calibration, cycle documentation.
5. Sintering (6 points):Furnace temperature profiling records (weekly), dew point monitoring (continuous), belt speed verification (daily), atmosphere gas purity certificates, sintering profiles documented per material, load/unload procedures.
6. Inspection (6 points):CMM and vision system capability, GR&R studies on all gauges (<10% for critical features), dimensional report format, AQL sampling plan, inspection operator training, retained sample storage.
Quick Q: How do I audit a MIM supplier?Use a 30-point checklist covering: quality system certification (IATF 16949), powder receiving inspection (PSD and oxygen tested per lot), feedstock MFI control (±5%), SPC on molding (shot weight), sintering capability (temperature profiling and dew point), and inspection (CMM GR&R <10%). The key question: can they trace a finished part back to its powder lot number and sintering profile?