Precision CNC Milling Services
We mill flight-, surgical- and semiconductor-grade parts from a 7,500 m² factory in Dongguan - 40+ machining centres, a 9-machine simultaneous 5-axis cell, and a Mitutoyo CMM lab behind every shipment.
● 40+machining centres
● 9+simultaneous 5-axis machines
● ±0.005 mmon critical features
● 30years
No MOQ · AS9102 FAI & CMM report on every order · NDA signed at CAD review
40+
CNC machining centres in-house
±0.005mm
Tolerance on critical features
52+
Countries shipped to
5–10d
Prototype lead time
Subtractive milling, run by people who do it every day
CNC milling removes material from a fixed block while a rotating cutter moves across three or more axes - the most flexible way to make prismatic and contoured metal and plastic parts in low to medium volume. That part is simple. Holding ±0.005 mm on a thin-wall aluminium housing after it has flown to Germany in a cargo hold is not.
MID has spent three decades on the fixturing, tool paths, coolant strategy and stress-relief steps that decide whether a milled part arrives flat and in tolerance - or arrives scrap. We run Mastercam and Siemens NX CAM with full Vericut simulation before any spindle turns, so first articles cut right the first time instead of being proven out on your part.
If a feature on your drawing is driving cost without earning it - a tolerance tighter than the function needs, an internal corner no standard tool can reach - we say so at quote, before you commit. That feedback is part of the quote, not a paid service.
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Milling capability at a glance |
SPEC |
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Axis configurations |
3 · 3+2 · simultaneous 5 |
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Standard tolerance |
±0.025–0.05 mm |
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Critical-feature tolerance |
±0.005 mm |
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Micro-feature tolerance |
±0.001 mm |
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Surface finish (as-milled) |
Ra 0.4–1.6 µm |
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Max work envelope |
≈ 600 × 600 × 500 mm |
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Minimum order qty |
1 piece |
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Quote turnaround |
12 business hours |
3-axis, 4-axis and simultaneous 5-axis milling
Most parts do not need five axes. The skill is knowing which configuration makes your part correctly at the lowest cost - and we quote it that way, not the way that fills the most expensive machine.
The workhorse for prismatic parts - plates, brackets, manifolds, enclosures and covers with features on one or two faces. Fast to fixture, fast to program, lowest cost per part for the right geometry.
- Plates, base mounts, sensor brackets
- Pockets, slots, bores, tapped holes
- High-speed machining for aluminium volume work
A rotary axis lets us reach multiple faces in one setup, cutting the number of fixtures and the tolerance error that stacks up every time a part is re-clamped. The right choice for housings and parts with features on several sides.
- Multi-face housings, valve bodies
- Compound-angle holes and pockets
- Fewer setups = tighter position tolerance
Where MID built its reputation. Nine simultaneous 5-axis machines cut undercuts, swept surfaces, intersecting bores and deep pockets that 3-axis simply cannot reach - fixtured once, machined complete, measured against a single zero point.
- Monolithic aerospace brackets, impellers
- Surgical-robotic articulation joints
- Optical mounts, vacuum-chamber bodies
The equipment your part actually runs on
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Cell / platform |
Machines |
Typical work envelope |
What it makes |
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Simultaneous 5-axis cell |
9 units - small-part & aerospace platforms |
≈ 500–600 mm travel |
Undercuts, 3D contours, monolithic housings, impellers |
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High-speed precision drill-tap |
5 × FANUC Robodrill α-D21MiA / D21MiB Plus |
Compact, 2 with 4th-axis rotary |
Micro features < 0.5 mm, high-mix aluminium & stainless |
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Turn-mill centres |
Doosan turn-mill, Swiss-style sliding-head lathes |
Bar & chuck work |
Shafts, connectors, milled-and-turned parts in one setup |
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3-axis VMC line |
Vertical machining centres |
Up to ≈ 800 mm table |
Plates, brackets, manifolds, enclosures |
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Metrology lab |
Mitutoyo CMM, optical comparators, height & surface gauges |
20 ± 1 °C climate-controlled |
First-article & in-process dimensional verification |
What we can actually hold - and how we prove it
These are the tolerances we commit to in writing, by feature type and material. Every value is verified on a Mitutoyo CMM, not signed off by eye.
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Feature / characteristic |
Standard |
Precision (on request) |
Verification |
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Linear dimensions |
±0.05 mm |
±0.005 mm |
CMM |
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Micro features (< 0.5 mm) |
±0.01 mm |
±0.001 mm |
Optical / CMM |
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Flatness |
0.05 mm |
0.005 mm |
CMM |
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Bore / hole true position |
0.05 mm |
0.02 mm |
CMM |
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Surface finish (as-milled) |
Ra 1.6 µm |
Ra 0.4 µm |
Profilometer |
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Surface finish (polished) |
Ra 0.8 µm |
Ra 0.2 µm |
Profilometer |
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Tapped / threaded holes |
UN, UNJ, UNF, metric M |
NPT, BSPP, custom |
Plug / ring gauge |
Metals and engineering plastics, with the milling notes that matter
Material choice drives weight, corrosion resistance, regulatory acceptance and cost more than almost any other decision. Here is how the families we mill daily actually behave on the machine.
High-speed milled with flood coolant to clear heat and stop built-up edge. The default for lightweight brackets and housings.
Low surface speed, heavy chip load, rigid setup and through-tool coolant. Aerospace and medical staple.
Work-hardens fast - heavy continuous feeds keep the edge under the hardened layer. Passivation to ASTM A967 available.
Tough, abrasive and work-hardening. Coated carbide or ceramic at low speed, maximum rigidity, for hot-section parts.
C360 mills fast and clean for fittings; C101 is gummy and needs razor-sharp polished tooling for electrical parts.
Hard-milled after heat treat to ~60 HRC with trochoidal paths and CBN tooling for dies and wear parts.
High RPM, sharp uncoated tools and air blast to clear heat. Stable, biocompatible options for medical and semicon.
Abrasive glass fibre demands PCD tooling, dry cutting and HEPA dust extraction for electrical insulation parts.
Five things that decide what a milled part costs
Small drawing changes often cut price 20–40% with zero loss of function. Here is the honest engineering version - the same notes we send back with a DFM review.
Internal corner radii
A milling cutter is round, so inside corners always carry a radius. Specifying a sharp internal corner forces EDM or a slow small-tool finish. Allow a radius of at least 1/3 of the pocket depth and the part runs faster and cheaper.
Wall thickness
Walls below ~0.8 mm in metal (1.5 mm in plastic) chatter and deflect. We can mill thinner with special fixturing and stress relief, but it costs - tell us if the thin wall is functional or just inherited from the model.
Pocket depth-to-width
Deep, narrow pockets need long tools that flex and leave taper. Keeping depth under ~4× the tool diameter holds tolerance; deeper than that, expect a 5-axis approach or a documented finish trade-off.
Tolerance only where it counts
A blanket ±0.01 mm on every dimension multiplies cost across the whole part. Tag the three or four features that mate or seal as critical and leave the rest at standard - the function is identical, the price is not.
Undercuts & tool access
Features a straight tool cannot reach need 5-axis, T-slot cutters or a redesign. If an undercut is there for assembly clearance, there is often a simpler geometry that machines in one setup.
Threads & inserts
For soft metals and high cycle counts, a threaded insert outlasts a cut thread. We thread-mill hardened and aerospace work and verify every batch with plug or ring gauges - call out the standard and class on the print.
The documentation that aerospace and medical buyers need is included by default - not quoted as a paid add-on after the fact. It is how a part stays auditable from mill heat to your incoming inspection.
We hold AS9100D for aerospace and ISO 13485 for medical simultaneously, both on an ISO 9001:2015 foundation - a dual certification almost no Chinese machine shop maintains. Your drawings sit on access-controlled servers and a mutual NDA is signed at CAD review, before any file changes hands.
AS9102 First Article InspectionFull
dimensional layout on first articles for aerospace work
Material certificates
Traceable to the mill heat number - no counterfeit risk
Mitutoyo CMM dimensional report
Critical features measured and recorded, not eyeballed
Process traveler
Every operation and inspection step logged for the lot
Finish & passivation certs
Profilometer finish and ASTM A967 passivation where specified
Cleanroom records when required
ISO 19227 cleaning & ISO 5 packaging for medical / semicon
Six sectors where the part has to be right the first time
From drawing to milled part in four steps
Questions engineering buyers ask about milling
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What tolerances can you hold on milled parts?Standard milled tolerance is ±0.025–0.05 mm, which covers most parts. On critical mating or sealing features we hold ±0.005 mm, and on micro features below 0.5 mm we hold ±0.001 mm. Achievable tolerance depends on material, geometry and part size, so we confirm exactly what we can hold on your specific features - in writing - before you order. Every critical dimension is verified on a Mitutoyo CMM in our 20 ± 1 °C metrology lab.
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Does my part need 3-axis or 5-axis milling, and how does that affect price?If all your features sit on one or two faces - plates, brackets, simple housings - 3-axis is faster and cheaper, and that is what we will quote. Parts with features on several faces benefit from 4-axis or 3+2 indexing, which cuts setups and tightens position tolerance. Simultaneous 5-axis is for undercuts, swept surfaces and intersecting bores that straight tools cannot reach. We quote the configuration your part actually needs to be correct, not the most expensive machine available.
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What is the largest part you can mill?Our 5-axis cell handles roughly 500–600 mm of travel, and our 3-axis VMC line takes tables up to about 800 mm. Most precision milled parts we ship are well inside that envelope. If your part is larger, send the drawing - we will tell you honestly whether it fits our machines or recommend how to break it into an assembly.
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What materials do you mill?Aluminium (6061, 7075, 6082, MIC6), titanium (Ti-6Al-4V Grade 5 and Grade 23 ELI), stainless (303, 304, 316L, 17-4 PH, 440C), Inconel 718, copper and brass (C101, C360), tool and alloy steels (D2, 4140), and engineering plastics and composites (PEEK, POM, PPSU, Ultem, G10/FR4). If you are unsure which grade fits the load and environment, our engineers will recommend one at quote.
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Do you machine one-off prototypes, or only production?Both, and there is no minimum order quantity. We routinely run single-piece prototypes and five-piece R&D samples in 5–10 working days, and we do not penalise low volume with disproportionate setup fees. When your design freezes, the same part moves to our production cell with identical process documentation and the same project manager - so you never re-qualify the supplier to scale up.
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What surface finishes can you apply to milled parts?As-milled finishes run Ra 0.4–1.6 µm depending on material and tooling, down to Ra 0.2 µm with polishing. In-house finishing includes bead blasting, tumbling, deburring, brushing and passivation to ASTM A967. Anodising (Type II and Type III hardcoat), electroplating, powder coating, electropolishing and DLC are handled by audited partners inside our local Dongguan cluster - coordinated as one order so you receive a finished part, not a machined blank.
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How fast can I get a quote, and what files do you need?Upload a STEP, IGES, PDF or DWG file and you will have an itemised quote - material, machining, finishing, inspection and shipping broken out separately - within 12 business hours. A 3D model plus a 2D drawing with critical dimensions and tolerances gives the fastest, most accurate quote, but we can work from a model alone and confirm the details with you.