Six Checkpoints When Auditing a Robot Contract Manufacturer

Published: 2026-10-22 09:50 (UTC+8) | Method: on-site question set | Basis: common SMT / DIP / ICT process practice

For a robot, control boards and final assembly usually dominate cost. The failure mode is rarely “they cannot build it”. It is the sample passes and mass production drifts. Here are six checkpoints in process order, each with the evidence you can ask for.

1. Capacity claims: pin down the denominator

Ask for three numbers: SMT line count, theoretical placements per day, and actual placements per day. The gap between the last two tells you about utilisation and order mix.

• Equipment model: NPM series or NXT series are common; ask for the exact model and placement accuracy range.
• Smallest component: whether 01005 or 0201 is routine depends on machine and stencil process, not on a brochure.
• Changeover time: for high-mix low-volume work this matters more than theoretical throughput.

2. Reflow and AOI: make solder quality visible

• Ask for reflow profiles from the last three months and how they adjust for board thickness.
• Is AOI pre-reflow, post-reflow, or both? Which stage’s first-pass yield (FPY) is being reported?
• What share of AOI rejects are re-judged by an operator, and against which criteria?

3. DIP and test: where mass production bottlenecks appear

Ask whether DIP uses single or dual wave soldering, whether the process is lead-free, and what the daily DIP output is.

Separate three test types:

1. ICT — opens, shorts and component values; needs fixtures and programs.
2. FCT — functional test per product; test items belong in the work instruction.
3. Burn-in — temperature or load, with duration and pass criteria written down.

4. Conformal coating: where environmental tolerance is decided

Robots work around dust, oil and humidity, so coating is not optional.

• Application method: spray, brush or selective coating; how are connectors and gold fingers masked?
• Thickness and cure: is thickness sampled, and is cure ambient or oven?
• Rework: what is the rework flow after coating, and is coating reapplied?

5. Assembly and burn-in: consistency and traceability

• Assembly line count and daily output per line; is there poka-yoke and a process card?
• Burn-in duration, load conditions and what is monitored.
• Key stations such as calibration and parameter flashing: who did it, when, and with which firmware version.

6. Outgoing inspection: the last checkpoint with hard evidence

• Sampling plan: AQL level or 100% inspection, stated explicitly.
• Serial-number traceability: can a unit serial number be traced back to a PCBA batch, SMT line and test record?
• Non-conforming product: who decides rework, scrap or use-as-is?

What these checkpoints cannot tell you

Everything above is verifiable, not a capability ranking. Placing 01005 does not mean a plant suits your product; many lines do not mean stable lead times. Two practical tests beat any checklist: run one of your own boards through their NPI flow, then sample a production lot and look at first-pass yield and rework rate.

For selection criteria in context, see the selection guides; to shortlist manufacturers by region, use the company directory; process basics are covered under robotics knowledge.