SinterWorks engineering team (sinterworks-pm.com)
MOST buyers meet powder metallurgy (PM) for the first time when a machined or cast part gets too expensive at volume. Sintering presses metal powder into near-net shapes with little waste, and at the right quantities it can cut part cost by 30- 60%. The catch: quality is designed in before the first gram of powder is pressed. This checklist covers what a procurement engineer should verify in a PM supplier — beyond the brochure.
1. Press capacity and part-size fit
PM parts are limited by press tonnage and die size. A 200-ton press tops out around 30 cm2 of projected area; an 800-ton press reaches roughly 100-120 cm2. Ask which presses your part would actually run on — not the largest machine in the shop, but the one that will carry your volume. If your part needs 500 tons and the supplier’s largest press is 300, you are looking at a split-die workaround that adds cost and weak sections.
2. Sintering infrastructure
The sintering furnace – not the press – decides consistency. Continuous furnaces (mesh-belt or walking-beam) suit high volumes of small parts; vacuum or batch furnaces handle stainless, high-alloy, and specialty atmospheres. Ask for furnace temperature uniformity surveys (a good shop runs them quarterly) and which atmosphere each furnace runs: endothermic gas for iron/copper grades, hydrogen or nitrogen-hydrogen for stainless and corrosion-critical parts.
3. Material grade literacy
A serious supplier speaks in MPIF designations: FC-0208 (iron-copper, the workhorse for structural parts), FN-0205 (iron-nickel for toughness), FL-4405 (stainless 400-series for corrosion exposure). Ask how they interpret MPIF Standard 35 data for your load case — minimum strength values are set at specific densities, and a supplier who quotes a strength number without stating the density behind it is telling on themselves.
4. Quality system and certs
Baseline: ISO 9001. Automotive volumes: IATF 16949 with PPAP documentation – level 3 as standard, not as an upcharge. Medical or aerospace: AS9100 or a documented path to it. On inspection, ask what is routine versus by request: density (Archimedes), hardness (HRB/HRC mapping), and dimensional reports from CMM should be standard on first articles. Crush tests (K-value) matter for bushings and bearings.
5. Secondary operations under one roof
Sizing for tight tolerances, CNC machining for features PM cannot form, oil impregnation for self-lubricating parts, steam treatment for sealing and corrosion resistance, heat treatment for wear surfaces. Every operation handed to a third party adds lead time and a quality handoff. Ask which of these are in-house – and get the names of the subcontractors that are not.
6. DFM collaboration before PO
The cheapest PM parts are ones nobody had to fix. A supplier who reviews your print before quoting – flagging wall thickness below 1.5 mm, sharp internal corners, or tolerance bands tighter than AGMA/PM practice – is saving you a tooling revision. Our free reference on this is the powder metallurgy DFM guide at sinterworks-pm.com/dfm-guide/ (tolerance and density bands by process); use it with any supplier, not just us. If a prospective vendor never pushes back on a drawing, expect problems after the die is cut.
7. Communication and export readiness
For overseas sourcing: who answers your emails, in what language, and how fast? Engineering questions deserve engineer answers, not sales intermediaries. Ask for a sample lead time in writing (typically 3-5 weeks including tooling for simple parts), how revisions are handled mid-tooling, and whether drawings are acknowledged with a signed tolerance review.
8. Red flags
– No furnace uniformity surveys, or “we don’t measure density” on structural parts
– Quotes with density unstated on strength-critical parts
– No IATF/PPAP for automotive volumes
– Tolerances quoted from machining tables instead of PM capability charts
– Refusal to name subcontractors
A 30-minute call covering these eight points will rank three suppliers faster than three weeks of RFQ ping-pong. Powder metallurgy rewards buyers who audit the process, not just the price.