How to vet a factory before you wire a deposit

The single most expensive mistake I see hardware teams make is wiring a deposit to a factory they've only met over email. The quote looks great, the photos look great, and three months later the parts don't fit, the finish is wrong, and the "factory" turns out to be a trading company that subcontracted your job to someone you've never heard of.

Here's the checklist I run before I let a client commit.

Confirm they actually make it themselves

Plenty of "factories" are really trading companies. That's not automatically bad — a good agent can be worth it — but you need to know which one you're dealing with, because it changes who controls quality and lead time.

Ask to see the production line that makes your kind of product. Not a showroom. Not a line making something adjacent. If they can't show you the machines doing the actual process your part needs, treat the quote as a reseller's markup, not a factory's cost.

Match capability to your tolerances

A factory that nails ±0.2 mm parts may quietly struggle at ±0.05 mm. Bring a drawing with your real tolerances and watch the room. The good ones push back on the hard dimensions and tell you what it'll cost to hold them. The risky ones say "no problem" to everything.

"No problem" to every requirement is a red flag, not a green light.

Look at capacity, not just capability

Can they make one? Probably. Can they make ten thousand, on schedule, while running three other clients' orders? That's a different question. Ask what else is on the line during your window, and how many of your units a day they can realistically ship.

Walk the floor

When I visit, I'm reading the things a video call hides: Is the place organized or chaotic? Is there any incoming-inspection or QC station, or do parts go straight from delivery to assembly? Are workers using fixtures and gauges, or eyeballing it? A tidy floor with real QC stations tells you more than any certificate on the wall.

Pay in a way that protects you

Never pay 100% up front. A typical structure is a deposit to start tooling/materials and the balance against inspection before shipment — so your last payment is leverage to fix problems. And make sure your contract says you own the tooling. If the molds are "theirs," your next price negotiation isn't really a negotiation.

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None of this requires you to fly to China yourself — it requires someone you trust to be on the floor asking these questions in the local language. That's most of what I do.