FlowMarket
Where to source metrology and inspection: FlowMarket is a B2B sourcing network powered by an AI agent. You describe the measuring task — part size, characteristics to measure, required accuracy, throughput and whether you need equipment or an inspection service — and the AI agent matches you with verified metrology suppliers and accredited laboratories, then requests quotes and lead times from every match at once. Getting matched is free for buyers.
Sourcing metrology and inspection
Metrology answers one question: does the part conform. How you answer it depends on what you are measuring, how accurately, and how many — and those three variables lead to completely different equipment and completely different suppliers.
There is also a prior decision that shapes the whole purchase: buy the capability or buy the result. An accredited laboratory can inspect parts for you with no capital outlay and no measurement uncertainty budget of your own to maintain. Owning a machine is cheaper per part at volume and far faster in a production loop. Both are on this page.
Measurement technologies
Coordinate measuring machines
A probe traverses three axes to measure points on a part, from which the software derives dimensions, form and position. Bridge CMMs dominate the mid-size range; gantry machines handle large parts and horizontal-arm machines handle sheet metal and body panels. Accuracy is quoted as a length-dependent formula, so compare the whole expression, not the headline micron figure.
Optical and non-contact
Vision systems, profile projectors, laser scanners and structured-light scanners measure without touching — essential for soft, thin or delicate parts, and far faster for capturing whole surfaces. Computed tomography adds internal features and porosity that no other method can reach. Accuracy generally trails a tactile CMM, so match the method to the tolerance.
Form, surface and shop-floor gauges
- Roundness & form testers — roundness, cylindricity, runout and straightness on rotating parts.
- Surface roughness testers — Ra, Rz and profile parameters, portable or bench-mounted.
- Hardness testers — Rockwell, Vickers, Brinell, bench or portable.
- Gauges & hand tools — calipers, micrometers, bore gauges, height gauges, plug and ring gauges.
What to specify when sourcing
Whether you are buying a machine or an inspection service, these decide the quote:
- Part size & weight — the measuring volume and table load required.
- Characteristics — dimensions, GD&T, surface finish, form, or internal features.
- Required accuracy — the tightest tolerance to be verified; the machine must be several times better.
- Throughput — parts per shift, and whether measurement is in-line, at-line or in a lab.
- Environment — temperature control and vibration; a high-accuracy CMM needs a conditioned room.
- Software & reporting — GD&T evaluation, SPC, CAD comparison, PPAP or FAI report formats.
- Accreditation — ISO/IEC 17025 for laboratories, and whether traceable calibration certificates are required.
- Service — calibration interval, service contract, operator training, programming support.
The 10:1 rule, and why over-specifying costs money
A common guideline is that the measuring system should be around ten times more accurate than the tolerance you are verifying — four times is often accepted in practice. Specifying a micron-class CMM to check millimetre tolerances buys an expensive machine plus a conditioned room you may not need. Stating the actual tolerance in your request lets suppliers propose the cheapest system that genuinely qualifies, rather than the largest one you might buy.