The buyer's checklist we use when customers audit us — capacity, quality system, IP protection, total cost and a scoring matrix you can fill in on a call or a plant visit.
Most supplier evaluations fail in the same direction: they over-weight the machine list and under-weight everything that actually predicts your experience — who does the DFM, what gets inspected and reported, and how the shop behaves when a drawing has a problem. This guide is the structure we hand buyers who ask "how should we evaluate you?"
· The 6-section evaluation framework (capacity, quality system, engineering, IP, cost, logistics)
· 24 questions to ask, with the answers that should raise a flag
· A 100-point scoring matrix you can fill in during a call or audit
· The total-cost model: unit price vs rework, freight and schedule risk
· A one-page NDA and file-handling checklist
Prefer to just talk? Send an RFQ — standard quotes within 4 working hours.
Ask what percentage of the claimed machine list is running during your visit — or in a video call, ask for a live walk-through of the floor. Questions that cut through: Which machines would my part run on? What happens in your busiest week? Who owns my job from PO to shipment? A 5-axis part quoted on a 5-axis shop should be traceable to a specific machine and a specific programmer.
Certificates on the wall are a starting point, not an answer. Ask: Is first-article inspection performed on every production run, or only the first order? Which CMM model, how many, and who operates them? Is material traceable to heat lot? Can I get the CMM report with the shipment, without asking twice? A shop that measures everything on hand calipers cannot hold ±0.003 mm honestly — the instrument must match the tolerance.
Send a deliberately imperfect drawing (a tight callout on a non-functional face, an awkward internal corner) and see what happens. A good supplier flags it before quoting. A poor one prices it silently or ignores it. This single test predicts your whole relationship better than any sales deck.
Will they sign an NDA before receiving files? Where do customer files live, and who can access them? Is the production floor open to other customers' staff? We sign NDAs as standard before drawings arrive and restrict project access inside the plant — treat anything less as a deal-breaker.
Build a simple model: unit price + finish + freight + expected rework rate + schedule risk. A shop 15% cheaper per piece with 5% rework and no CMM reports usually loses money the first time a nonconformance lands in your assembly plant. Ask for the failure modes: what happens when a part is late or out of spec, who pays for rework, and what the communication loop looks like at 2 pm your time.
| Dimension | Weight | What earns full marks |
| Process capability match | 25 | Named machine + programmer for your part; tolerance grade verified by matching instrument |
| Quality system | 25 | 100% FAI, CMM reports per shipment, heat-lot traceability |
| Engineering engagement | 20 | DFM feedback before quote; DFM test drawing flagged |
| Responsiveness | 15 | Quote within one business day; engineer reachable directly |
| IP & confidentiality | 10 | NDA signed pre-RFQ; file access controlled |
| Commercial structure | 5 | Transparent line items; no surprise tooling |
Score two or three finalists on the same matrix and the decision usually makes itself. The point is not the arithmetic — it's forcing the same questions to every supplier, so you're comparing answers instead of sales styles.
