A purchase order is easy to send and hard to walk back. Once it's signed, you're locked into a fabricator's process, tolerances, and quality system, whether or not they actually match what your board needs. A short conversation before that PO goes out can save weeks of rework later. Here are ten questions worth asking, and why the answers matter.

1. What IPC Class Do You Build To By Default?

This is one of the most consequential questions on the list, and the one most buyers skip. The IPC Class 2 vs Class 3 distinction determines the acceptance criteria your boards are held to, not just a paperwork formality. Class 2 covers general electronics where field failure isn't catastrophic. Class 3 requires higher plating thickness, tighter annular ring tolerances, and stricter inspection for applications where failure could be dangerous or extremely costly, think aerospace, defense, and medical devices.
If you're unsure what is IPC Class 2 versus what your program actually needs, ask directly which class the fabricator defaults to and whether they can build to a higher class on request. A shop running only Class 2 production lines can't simply say yes to a Class 3 requirement without real process changes.

2. How Are Your PCBs Made, Step by Step?

Understanding how PCBs are made at a specific shop, not in general, tells you where problems are likely to originate. Ask the fabricator to walk through their PCB fabrication process: imaging and etching, drilling, plating, lamination for multilayer boards, solder mask, and final testing. A fabricator who explains their process in specific, plant-level detail, rather than a generic textbook answer, actually understands their own equipment and its limitations.

3. What Certifications Do You Hold, and Are They Current?

Certifications like AS9100, ISO 9001, and MIL-PRF-31032 represent audited quality systems, not just logos on a website. Ask for certificate numbers and expiration dates. ASC's quality certifications page is a useful example of the detail worth expecting: specific standards, specific scope, and a clear explanation of what each one covers.

4. Can You Show Me Test Data, Not Just a Spec Sheet?

Impedance tolerances, plating thickness, and material properties are easy to print on a datasheet. Ask for actual TDR reports, cross-section photos, or first article inspection data from a comparable past job. A fabricator confident in their process will have this on hand without hesitation.

5. What's Your Real Lead Time, Including Engineering Review?

Quoted lead time and actual delivery time often diverge because of DFM review cycles, material procurement, or panel scheduling. Ask specifically what happens between PO signature and the start of production, and what could extend that window.

6. Do You Perform DFM Review Before Production Starts?

A Design for Manufacturability review catches routing, spacing, or via issues before they become scrapped panels. Fabricators who skip this step and manufacture strictly to submitted files put the risk entirely on you. Ask whether DFM is standard practice or an added service, and how issues are communicated back to your team.

7. What Materials Do You Stock, and What Requires Special Order?

Standard FR-4 is usually on the shelf. High-frequency laminates, heavy copper, or specialty metal-backed constructions often aren't. Ask directly which materials are staged inventory versus special order, since the latter can add real time to your schedule even if the base lead time looks short.

8. How Do You Handle Traceability and Lot Documentation?

For regulated industries especially, every board should trace back to specific material lots, process logs, and inspection records. Ask what documentation ships with the order by default, and what's available on request if a field issue needs root-cause investigation later.

9. What Happens If a Design Doesn't Meet Your Process Capability?

Every fabricator has limits on minimum trace and space, hole size, and layer count. Ask what happens when a design falls outside those limits, do they flag it during quoting, during CAM review, or not until the panel fails inspection? ASC's design and incorporation guidelines are a good example of a fabricator publishing these limits upfront rather than leaving buyers to find out the hard way.

10. Who Do I Talk to When Something Goes Wrong?

Production issues happen even with the best fabricators. What separates a good partner is a clear escalation path: a named engineering contact, not a generic support inbox. Before signing, confirm who owns your account and how quickly they respond when a question comes up mid-run. ASC's quick-turn services page outlines this kind of direct engineering support even under compressed timelines, which is a reasonable bar to hold any fabricator to.

Why This Vetting Matters More Than It Seems

None of these questions are exotic. They're the kind of due diligence that separates a smooth production run from a scrapped panel discovered weeks into a schedule. American Standard Circuits (ASC) and Sunstone Circuits bring over 50 years of combined experience to this exact process, holding AS9100 Rev D, ISO 9001, and MIL-PRF certifications while supporting everything from prototype to full production runs.

If you're preparing to send out a PO, request a quote from ASC or get in touch with the engineering team to walk through these questions before your design is locked in.