SINTSSINTSPrecision Metal Components
Buyer GuideBy XiaoDiJune 25, 2026

How to Review First Article Samples for Metal Parts

First article review is where many custom metal part projects become real. A sample may look good at first glance, but the buyer still needs to check whether the part matches the drawing, fits the assembly, and supports the intended production route.

This guide gives buyers a simple way to review samples for MIM, powder metallurgy, and other OEM metal parts without turning the process into an engineering lecture. The goal is to catch issues early and move toward stable production with fewer surprises.

Metal parts sample, caliper, and checklist on a workbench
First article review becomes easier when the sample, the drawing, and the inspection tools are aligned.

Start with the drawing

The sample should always be checked against the drawing first. That sounds basic, but it is the quickest way to avoid missing an issue that later becomes expensive. Confirm the overall size, critical features, hole positions, thickness, and any dimensions that affect assembly or function.

Check the surfaces that matter

Not every surface carries the same weight. Some parts can tolerate cosmetic variation in hidden areas but need cleaner treatment on visible or functional faces. Buyers should separate the surfaces that matter for appearance, wear, sealing, sliding, or contact from the ones that are not critical.

Review fit, not just appearance

A sample can look polished and still fail in assembly. Check how the part sits in mating components, whether holes and edges behave as expected, and whether the part supports the intended motion, lock function, or load path. This is especially important for parts used in locks, medical tools, appliances, and mechanical subassemblies.

Compare the sample against the intended process

A useful first article review should also tell the buyer whether the process route still makes sense. If the part needs repeated machining, heavy correction, or awkward secondary steps, the supplier should revisit whether MIM, PM, or another route is the best fit.

Small metal parts process review image
Process choice and sample review belong together, not in separate conversations.
MIM medical parts
Sample review is especially important when the part serves a regulated or sensitive application.
Powder metallurgy bushing
Structural parts often need sample review focused on fit and contact behavior.

A practical sample checklist

  • overall dimensions and critical tolerances
  • assembly fit and functional movement
  • surface finish on visible or contact areas
  • material or heat-treatment expectations
  • need for machining, polishing, or plating
  • packaging and handling condition

What to ask the supplier after review

If the sample is close but not yet right, ask the supplier which issues are geometry-related, which are process-related, and which can be solved with secondary operations. That keeps the conversation practical and helps the project move toward a better version of the same part instead of starting over.

Conclusion

First article review should be simple, disciplined, and tied to the part's real use. When buyers focus on drawing, fit, finish, and process fit together, the sample becomes a useful step toward stable production rather than just a checkpoint.