How to Choose a Micro Machining Supplier

By the Micropartz editorial team · Published October 30, 2026

Finding a micro machining supplier is harder than finding a CNC shop. Almost every machine shop describes itself as precision, and many list micro machining among their services. Far fewer run the machines, tools and measurement that parts under 10 mm with ±0.005 mm features need. This guide gives buyers a practical way to tell the difference, the questions worth asking and a checklist to compare shops. If you are still defining the part, the micro machining buyer’s guide covers processes and tolerances first.

Precision shop or micro machining shop

A general precision shop and a micro machining shop can look similar on a website. The differences show up in equipment and habits.

Area	General precision CNC shop	Micro machining shop
Turning	CNC lathes, bar feeders	Swiss-type or sliding-head lathes, guide bushings, live tools
Milling	Standard machining centers, 10,000 to 15,000 rpm	High-speed spindles, often 30,000 rpm and above, 5-axis
Smallest routine tool	1 to 3 mm	0.1 to 0.5 mm
Workholding	Vises, standard fixtures	Precision collets, custom micro fixtures
Measurement	Calipers, micrometers, standard CMM	Small-stylus CMM, vision system, measuring microscope
Environment	Shop floor	Temperature-controlled measuring room
Handling	Bins and bags	Trays, part catchers, individual packing
Typical parts	20 to 500 mm	1 to 10 mm, or micro features on larger parts

Typical differences, not a strict classification.

A shop does not need every item on the right-hand side for every part. A turned pin at ±0.01 mm does not need a micro mill. But if your tightest feature is ±0.005 mm on a 0.4 mm bore, you need a shop that owns and uses the measurement to prove it.

Questions that reveal real capability

Send these questions with your RFQ or ask them on the first call. The answers are quick for a real micro machining shop and hard to fake for others.

1. Which machines would you run this part on? Expect a named machine type, a spindle speed or bar capacity and a reason.
2. What is the smallest tool you use in production, not in a demo? Expect a number and a material.
3. How will you measure the tightest feature? Expect a method, for example pin gauges for the bore and CMM for position, and an honest word on uncertainty.
4. Can you share a first article report from a similar part? With the customer name removed. The format tells you how the shop works.
5. How do you deburr and clean parts this small? Expect a method and an inspection magnification.
6. What would you change on this drawing? Good shops always have DFM suggestions for micro parts. A shop with no questions has either not looked closely or plans to add margin.

The guide on how micro parts are measured explains what good answers to question 3 look like.

Red flags

Watch for these signs, especially when a quote is far below the others.

• No questions at all on a tight-tolerance micro part. Micro parts almost always raise DFM points.
• Generic machine lists with no spindle speeds, no Swiss-type machines and no measuring equipment.
• Tolerance promises without a method. “We can hold ±0.002 mm” without saying how it will be measured.
• Photos of large parts only. Precision on a 200 mm plate says little about a 3 mm pin.
• Certificates that cannot be shown. Ask for the certificate and check the scope and expiry date.
• Unwillingness to sign an NDA before seeing detailed drawings, when your part needs one.

Documents and quality system

Match document requirements to your industry.

Industry	Usually expected	Often requested
General industrial	ISO 9001, CoC	Material certificates
Medical devices	ISO 13485 or quality agreement, material traceability to lot	First article report, process validation support, cleanroom packaging
Semiconductor	ISO 9001, cleanliness spec	Material certificates, specific packaging
Aerospace	AS9100	First article inspection to AS9102, full traceability
Optics and instruments	ISO 9001	Measurement records for critical features

Typical expectations, not regulatory advice.

Certificates alone do not prove micro machining capability. A shop can be ISO 9001 certified and still lack the measurement for a ±0.005 mm micro feature. Treat certificates as a minimum, then check capability separately.

IP protection and NDA

Micro parts are often at the heart of a product: a medical instrument tip, a sensor, a connector. Protecting the design matters. Common practice:

• Send a short description first and the full drawing only after an NDA where needed.
• Mark drawings with ownership and confidentiality notes.
• Share only what the shop needs to quote. Assembly drawings can usually wait.
• Ask how files are stored and who at the shop can see them.

On Micropartz, ticking the NDA box on the RFQ means matched shops see only a short preview without your name or files until an NDA is signed.

Supplier region

Micro machining capacity exists in many countries. The United States, Switzerland and Germany have long traditions in Swiss-type and precision turning. Japan, Korea and Taiwan have strong precision machining bases. Southeast Asia, including Vietnam, has a growing number of precision shops, though fewer that specialize in Swiss-type micro work. Choose a region based on volume, IP sensitivity, lead time, logistics and cost targets, then compare shops within it on capability.

Start with a trial order

Even a well-qualified shop is an unknown until the first parts arrive. Most experienced buyers place a small trial order before committing volume. A good trial order is designed to reveal the things that matter later.

• Use a real part, not an easy one. Pick a part with your tightest tolerance and smallest feature, so the trial tests what production will need.
• Ask for the full documentation you will need in production. First article report, material certificates and certificate of conformance. If the paperwork is weak on 20 parts, it will not improve on 20,000.
• Measure the parts yourself. Compare your results with the shop’s report on the critical features. Small differences are normal. Systematic differences mean the measurement methods do not match and need to be aligned now.
• Check packaging and cleanliness on arrival. Bent pins, tangled parts and residue from cutting oil are process problems, not bad luck.
• Note how the shop communicates. Did it report a problem early or hide it until delivery? Did it answer technical questions within a day or two?

Trial order result	What it usually means	Next step
All features in tolerance, report matches your measurement	Process and measurement are under control	Move to pilot quantity
Parts good, report differs from your measurement	Different methods or fixturing	Align methods before scaling
Burrs or residue on some parts	Deburring or cleaning not yet defined	Agree edge condition and cleaning spec
Critical feature out, shop reported it first	Honest shop, process needs tuning	Allow a second trial
Critical feature out, not reported	Weak inspection or communication	Reconsider the shop

Typical interpretations for orientation, not a formal qualification procedure.

A trial order costs more per part than a production run, but it is much cheaper than finding a measurement or process problem after the first large delivery. For regulated parts, the trial also feeds your own supplier qualification records.

The trial order is expanded, with sample sizes and pass rules, in micro parts trial lot.

A checklist to compare shops

Use the same checklist for every shop so the comparison is fair.

Criterion	Shop A	Shop B	Shop C
Right process for the geometry (Swiss-type, micro mill, EDM)
Smallest production tool fits your smallest feature
Measurement method for tightest tolerance stated
Sample first article report reviewed
DFM questions received
Certificates shown and in scope
NDA signed if required
Quote at 2 to 3 quantities with lead time
Delivery terms clear (EXW, DDP)

Price belongs at the end of the comparison, not the start. The guide to micro machined parts cost explains why quotes differ and which differences are real.

For the whole route from region to landed cost, read our guide to micro machining services.

Getting matched instead of searching

Searching, emailing and qualifying shops one by one takes weeks. Micropartz is a matching service built for this niche. You send one RFQ with your drawing, material, quantity, tightest tolerance and preferred supplier region. We match it with up to 3 shops that run the right process and measurement, and reply within 24 business hours. Shops quote you directly, you pay nothing and there is no commission on the order. Read more on the micro machining page, or send an RFQ when your drawing is ready.

Frequently asked questions

Reviewed against

• ISO 9001:2015, Quality management systems, Requirements
• ISO 13485:2016, Medical devices, Quality management systems
• Wikipedia: Non-disclosure agreement

Numbers in this guide are typical values for orientation. The drawing, the material certificate and the matched shop set the real ones.

Keep reading

• Micro Machining: A Buyer's Guide to Very Small Precision Parts
• How Micro Parts Are Measured: CMM, Optical and Vision Inspection
• What Micro Machined Parts Cost and Why Inspection Is Half of It