Micro CNC machining is not just standard CNC work on smaller parts. It requires the right machines, tooling, and inspection methods to hold micron-level tolerances on features often under 10mm. This guide explains how micro machining works, when Swiss-type machining matters, what tolerances are realistic, and how to verify a factory before you request quotes.
Micro CNC machining is CNC machining of parts or features generally under 10mm, often to tolerances measured in microns rather than thousandths of an inch. It demands different equipment, different tooling, and different verification than standard CNC work - which is exactly where a lot of sourcing goes wrong.
This guide covers what separates micro machining from standard CNC, what Swiss-type machines do differently, how tight tolerances actually get, and what sourcing teams should check before sending a micro-scale RFQ to precision CNC machining factories in China.
Micro CNC machining is the use of computer-controlled mills, lathes, Swiss-type machines, EDM, or grinding equipment to produce parts or features generally under 10mm, frequently to tolerances in the single-digit micron range.
The distinction from standard CNC machining is not just size. At this scale, tool deflection, thermal expansion, burr formation, vibration, and even the structural rigidity of the workpiece become limiting factors in ways they are not on a 50mm bracket.
A 0.02 mm deviation may be acceptable on a general mechanical component. On a micro connector pin, medical component, or precision instrument feature, the same deviation can make the part unusable.
Micro CNC machining and standard CNC machining share the same basic principle - removing material with a controlled cutting tool - but they differ sharply on equipment, tooling, tolerance, inspection, and process risk.
|
Factor |
Micro CNC Machining |
Standard CNC Machining |
|
Typical feature size |
Under 10mm |
10mm and up |
|
Typical tolerance |
±0.002-0.01 mm |
±0.05-0.13 mm |
|
Equipment |
Swiss-type lathes, high-speed micro mills, EDM, grinding |
Standard 3/4/5-axis mills, conventional lathes |
|
Tooling |
Sub-millimeter end mills, micro drills, fine turning tools |
Standard-diameter tooling |
|
Inspection |
Optical comparators, vision systems, high-magnification CMM |
Standard CMM, calipers, gauges |
|
Main risk |
Tool deflection, burrs, thermal movement, inspection limits |
Setup error, tolerance stack-up, surface finish, cycle time |
Questions about tolerance classes, quality assurance, and certifications that apply to both micro and standard CNC work are covered in our CNC machining China FAQ.
Swiss-type machining is a CNC turning process that uses a guide bushing positioned close to the cutting tool. The guide bushing supports the bar stock right at the point of cut, reducing deflection and chatter on small-diameter parts.
That support is what allows tight tolerances on parts that would flex on a standard CNC lathe, where the distance between the chuck and the cutting tool leaves long, thin stock unsupported.
The tradeoff is setup complexity. Swiss-type machines need their guide bushing matched to the bar stock diameter, and tooling changeovers can take longer than on a standard lathe. That is part of why not every CNC shop invests in this equipment, and why “we can do micro parts” does not always mean “we run Swiss-type machines.”
This matters because most genuine micro turned-part capability runs through Swiss-type equipment, not standard lathes scaled down.
Note. A factory saying it can make small parts is not the same as a factory running Swiss-type machines. For micro-scale turned parts, ask for the machine type before comparing quotes.
Genuine micro CNC machining can hold tolerances down to single-digit microns on suitable features, but achievable tolerance depends on material, geometry, equipment, fixturing, thermal stability, and inspection capability.
In Haizol's 2026 China CNC Machining Industry Report, 48.2% of analyzed factories offer Swiss-type machining to tolerances of ±0.005 mm. That is a specific, verifiable capability claim - the kind of evidence worth asking for instead of accepting “extremely precise” as an answer on its own.
|
Capability |
Typical Tolerance Range |
What to Verify |
|
Swiss-type machining |
±0.005 mm on suitable small-diameter parts |
Machine type, guide bushing setup, sample inspection report |
|
Micro milling |
±0.005-0.01 mm depending on geometry |
Spindle speed, tool size, workholding, burr control |
|
EDM / fine features |
Single-digit micron capability on suitable features |
Feature depth, material, electrode or wire size, inspection method |
|
Standard CNC machining |
Often ±0.05-0.13 mm on general features |
Whether the tolerance is realistic for the part size |
The important question is not whether a factory claims ±0.005 mm. It is whether the factory has the equipment and inspection method to prove it on a comparable part.
Micro CNC machined parts are commonly made from stainless steel, titanium, brass, aluminum, copper alloys, and engineering plastics. The right material depends on strength, corrosion resistance, conductivity, biocompatibility, and machinability.
Medical device manufacturers use micro machining for surgical instrument components, connectors, implant hardware, dental components, and miniature fasteners. Electronics manufacturers use it for micro connectors, sensor housings, RF components, contacts, and small enclosures. Precision instruments, aerospace fuel system components, watchmaking parts, and miniature mechanical assemblies are also common applications.
|
Material |
Why It Is Used |
Common Micro Machining Applications |
|
316L stainless steel |
Corrosion resistance and medical suitability |
Surgical tools, medical components, precision housings |
|
Titanium |
High strength-to-weight ratio and biocompatibility |
Implants, aerospace parts, medical hardware |
|
Brass |
Machinability and electrical conductivity |
Connector pins, contacts, fittings |
|
Aluminum |
Low weight and good machinability |
Instrument housings, miniature brackets, electronic parts |
|
Engineering plastics |
Electrical insulation and low weight |
Insulators, micro housings, medical device components |
Verify micro machining capability by checking equipment type, tolerance evidence, inspection method, and demonstrated minimum feature size. Do this before comparing prices.
Plenty of CNC shops describe their work as “micro machining” while actually meaning small parts on standard equipment, not genuine micron-level capability. That may be fine for simple low-tolerance components. It is risky for true micro work.
|
What to Verify |
What to Ask |
Why It Matters |
|
Equipment type |
Do you run Swiss-type lathes, micro-milling centers, EDM, or grinding equipment? |
Standard CNC machines may not hold micro-scale tolerances on small features. |
|
Tolerance evidence |
Can you provide an inspection report for a comparable part? |
Marketing claims are not enough for ±0.005 mm work. |
|
Inspection method |
Do you use optical inspection, vision systems, CMM, or high-magnification measurement? |
A factory cannot control tolerances it cannot measure. |
|
Minimum feature size |
What is the smallest hole, slot, wall, or boss you have produced and inspected? |
Published capability ranges may not match real production experience. |
|
Material experience |
Have you machined this exact material grade at similar feature sizes? |
Tool wear, burrs, and surface finish change by material. |
Micro-scale drawings leave less room for ambiguity than standard CNC drawings, because tolerances that would be rounding errors on a larger part can be the entire feature. Before submitting an RFQ, include:
Use Haizol's CNC machining RFQ workflow to match micro machining projects with factories that have relevant Swiss-type, micro-milling, EDM, grinding, or inspection capability. This matters because micro machining RFQs should not be routed only by process category. They should be matched by demonstrated capability: equipment, tolerance range, material experience, and inspection method.
Go to Haizol's Swiss CNC machining services page or submit a request through the RFQ form. In the requirements field, state that the project requires micro CNC machining and list the feature sizes, tolerances, material grade, inspection requirements, and target quantity.
Upload both the 3D CAD model and 2D technical drawing. The 3D model helps factories assess manufacturability, while the 2D drawing confirms critical tolerances, surface finish, datums, and inspection notes.
Before treating a quote as comparable, ask each factory to confirm its equipment and provide evidence for the required tolerance. For micro parts, a lower quote is not useful if the factory cannot inspect the feature after machining.
|
Quote Check |
What It Means |
What to Ask the Factory |
|
No Swiss-type equipment listed |
The factory may be quoting small parts on standard lathes. |
Confirm the machine type and whether guide-bushing Swiss turning is available. |
|
No inspection method stated |
The factory may not be able to verify micron-level features. |
Ask for CMM, optical, or vision inspection capability and sample reports. |
|
Tolerance claim is vague |
“High precision” does not define a measurable standard. |
Ask for achieved tolerance on a comparable part and the measurement method used. |
|
Material grade missing |
The quote may assume an easier-to-machine substitute. |
Confirm exact grade, certificate availability, and prior experience with that material. |
|
Minimum feature size missing |
The factory may not have checked the hardest feature on the drawing. |
Ask them to identify the smallest feature and confirm how they will machine and inspect it. |
Once quotes arrive, compare factories by equipment, tolerance evidence, inspection method, material experience, lead time, and certifications before comparing unit price. For standard CNC work, price differences often come from labor rate, machine time, and material cost. For micro CNC machining, price differences often come from whether the factory is quoting the right process at all.
Note. The most common mistake is treating “small CNC parts” and “micro CNC machining” as the same capability. They are not. Micro machining requires the equipment and metrology to produce and verify very small features repeatedly.
On well-equipped Swiss-type lathes and dedicated micro-milling centers, reliable slot widths and drilled holes often start around 0.1-0.5mm. Hole diameters from 0.1mm upward are achievable with micro-drills using careful peck cycling and high-speed spindles. Tolerances for critical dimensions can reach ±0.002-±0.005mm on suitable features under stable thermal conditions. Standard CNC shops without micro-specific equipment generally treat ±0.01mm as a practical floor. Below that, measurement capability becomes the binding constraint.
Micro machining targets feature sizes under 10mm with tolerances often below ±0.01 mm, using equipment like Swiss-type lathes, high-speed micro mills, EDM, and grinding. Standard CNC machining typically holds wider tolerances on larger features using conventional mills and lathes.
Swiss-type machining uses a guide bushing that supports bar stock close to the cutting tool, reducing deflection on small-diameter parts. This is the equipment category most associated with genuine micro-scale turned-part tolerance capability.
Ask for the specific equipment type, a sample inspection report showing achieved tolerances on a comparable part, the inspection method used, and confirmation of the factory's minimum demonstrated feature size. A vague answer to any of these is a warning sign.
Medical devices, electronics, precision instruments, aerospace components, and watchmaking use micro CNC machining most often because these industries require small parts with tight tolerances, reliable inspection, and controlled materials.
The gap between a shop that says “we do micro machining” and one that runs verified Swiss-type lathes with documented tolerance evidence is the gap between a conforming part and scrap. Most suppliers will quote any tolerance if there is no mechanism to verify the claim before the job starts.
Equipment type, tolerance evidence on a comparable part, and minimum demonstrated feature size - not stated, demonstrated - are the three answers that separate a factory worth qualifying from one that will cost you revision cycles to discover it was not the right fit. Are you ready to collect quotes from multiple verified factories with Swiss machinery capability? Submit a micro CNC machining RFQ on Haizol with your drawing, material grade, feature sizes, and inspection requirements to receive quotes from capability-matched CNC machining factories.