CNC Machining Company Services
Mill-turn combines milling and turning in one setup for parts that would otherwise need multiple fixtures. It protects tolerance at the interfaces and removes the handling between a lathe and a mill. For shafts with milled features it is often the lowest-total-cost path at any volume, and it shines at high volume where every avoided handling step compounds.
The reason is concentricity. When a shaft is turned and then moved to a mill, the milled features are located off a re-indicated reference, and every re-indication adds a small error. When the part stays in one chuck and the milled features are cut against the same datum, the relationship holds without the error. For a shaft with a keyway, a cross-hole, or a milled hex, that relationship is usually the whole point of the part, and mill-turn is the process that owns it.
When does grinding make sense?
Grinding reaches ±0.002 mm, tighter than milling or turning, and serves fit or finish-critical features: shafts, ways, sealing faces, tooling. It is the service that rescues a tolerance milling cannot hold. If your drawing calls for it, ask whether the shop owns the grinders; we do, so the critical dimension stays inside the building.
Grinding is also where an outsourced step hides risk. A shop that subcontracts grinding loses control of the tightest dimension on the part. When you ask whether the grinders are on the floor, you are really asking who owns your tightest tolerance. If the answer is a partner, the critical dimension leaves the building and your lot rides on that partner's discipline.
The practical test is the drawing. If the tightest callout on the part is a bearing seat, a sealing face, or a way surface, ask directly whether the grinder that finishes it is in the same building as the mill that roughed it. The answer tells you whether the tightest dimension on your part is owned by the shop you hired or by a sub-contract you did not choose.
How does volume drive the process decision?
At low volume, minimize setup and prove the design. At high volume, minimize total handling and scrap, where Ppk ≥ 1.67 at the initial study on critical characteristics and Cpk ≥ 1.33 on general characteristics. Capability is reported per characteristic: every report names the feature, its tolerance band, the sample size, the sigma method, and the study window keeps yield up. The economic process moves as the quantity moves, and we state the recommended process for your volume with the quote, separating setup from piece price.
The trap is pricing the machine, not the part. A 5-axis rate looks expensive until you count the fixtures, deburr steps, and handling it removes. The opposite trap is staying on 3-axis past the point where re-fixturing costs more than the upgrade. The honest answer is a number for your quantity, not a preference stated as a rule.
Which tolerances does each service hold, and what do they cost?
Every service has a tolerance it holds comfortably and a tolerance it can only reach with extra care. Milling and turning hold ±0.003 mm (milling) / ±0.002 mm (turning) as standard; grinding reaches ±0.002 mm. The cost sits in the step between the two: a dimension that milling can hold is cheap, while a dimension that forces grinding adds a process, an inspection, and a per-part cost that repeats across the whole run.
| Service | Held tolerance | What pushes it over the line |
|---|---|---|
| 3/4/5-axis milling | ±0.003 mm | Tight positional callouts on multiple faces |
| CNC turning | ±0.002 mm | Roundness and runout on long parts |
| Mill-turn | ±0.003 mm (milling) / ±0.002 mm (turning) | Concentric interfaces between turned and milled features |
| Precision grinding | ±0.002 mm | Bearing seats, sealing faces, fine finishes |
The drawing is what assigns a dimension to a service. Reserve the tight tolerances for the features that mate or seal, and leave the rest on a general band, and the part lands in the cheap process. Stamp tight callouts everywhere and the part gets pushed into grinding whether it needs it or not, which is money spent on every unit of the batch.
How do surface finishes add cost as volume grows?
A surface finish is a per-part cost, so it is nearly invisible at one piece and a major line at ten thousand. The machined surface already carries a roughness set by the tool and feed; asking for finer than the function needs adds a finishing step. The ladder is simple: standard milling and turning leave around Ra 3.2 µm, fine milling or light grinding reach Ra 1.6 µm, precision grinding reaches Ra 0.8 µm, and lapping or polishing goes below that.
Secondary finishing — anodizing, plating, passivation, heat treatment — scales the same way. In-house steps are stated as such; partnered steps name the supplier and carry their certificate with your lot. The discipline is to specify the finish the function needs and nothing finer, and to decide who runs it before the volume exposes the cost.
Which secondary operations scale with volume?
Anodizing, plating, heat treatment, passivation, and assembly scale with the order. In-house steps are stated as such; partnered steps name the supplier and carry their certificate with your lot. Disclosing the partner keeps traceability complete as volume grows.
The disclosure is the point. A secondary step that is hidden is a step you cannot audit, and an un-auditable step is a risk you carry without knowing it. When the supplier names the partner and ships the partner's certificate with your lot, the chain stays complete, and complete traceability is what lets you isolate a problem later instead of guessing at it.
| Process | Earns its cost when | Adds cost without value when |
|---|---|---|
| 3-axis milling | Features on one or two faces, low volume | Five faces force re-fixturing at volume |
| 4-axis / 5-axis | Features on multiple faces, tight relationships | The part is prismatic and simple |
| Mill-turn | Milled features on a turned part, tight interfaces | Pure turning or pure milling |
| Grinding | ±0.002 mm fits, sealing faces, ways | Milling already holds the tolerance |
How do you challenge a process recommendation?
A process quote should tell you why, not just what. Before you accept a recommendation, ask questions that force the reasoning into the open.
- Which process does the quote assume, and what changes at my real annual volume?
- Would a cheaper process hold the tolerance, and what is the risk if it does not?
- Is the grinder or the 5-axis machine on your floor, or a partner's?
- Can you show setup and piece price as separate lines?
- Which secondary steps are outsourced, and who is the named partner?
What this shop actually runs
Ask for capability evidence and the answer should be specific. The facility behind this guide runs 100+ CNC machines on a 6,800 m2 floor in Dongguan, China, with 100+ staff. The machine list, by category:
- 5-axis machining centres (10+) - Mazak VARIAXIS I-600 (510/910/510 mm travel, 12,000 rpm, 22 kW, 71.6 N·m, 30-tool BT40) and Mazak INTEGREX I-250H S (B-axis 0.0001°, 24 kW, 124 N·m, 38-tool HSK-A63). Typical work: compound-angle parts, single-setup multi-face prismatic work, and aerospace fittings where datum transfer loss is unacceptable.
- 3-axis / 4-axis machining centres (50+) - Brother SPEEDIO S500Z2N / S700Z2N (10,000 rpm, 14/21-tool ATC, 0.7 s tool-to-tool, Z-axis 2.2 G) and Mazak VCE-430A L / VCE-570C L (10,000 rpm, 118 N·m, 24-tool ATC). Typical work: prismatic parts, plates, brackets, housings.
- Swiss-type turning centres (10+) - Citizen Cincom A20-3F7 (Φ20 mm, 10,000 rpm), TSUGAMI B0206-III / B0205-III (Φ20 mm, 0.1 µm), STAR SR-32JII / SR-32J Type N (Φ32 mm, 8,000 rpm). Typical work: long, slender rotational parts at ±0.002 mm.
- CNC turning centres (20+) - HEADMAN T70M/1250 (720 mm swing, 117 mm bore, 3,000 rpm, BMT75 12-station turret). Typical work: shafts, bushings, flanges up to ±0.002 mm.
- Wire EDM (5+) - Sodick AQ535L (550/350/300 mm travel, ±20° taper, 800 kg workpiece). Typical work: hardened tool steel, internal splines, sharp internal corners that milling cannot reach.
- Inspection: Hexagon CMM + 20+ gauges - Hexagon CMM for coordinate measurement, plus vision system, profilometer, hardness tester, coating thickness gauge, XRF for material verification. The 10:1 rule (gauge 10x more accurate than the band) is applied to every feature.
- Machine highlights - VARIAXIS I-600: one-setup multi-face 5-axis + MAZA-CHECK auto-calibration; INTEGREX I-250H S: DONE-IN-ONE mill-turn, B-axis 0.0001° + Ai thermal shield; SPEEDIO S500Z2N / S700Z2N: Z-axis 2.2 G + 0.7 s ATC; Swiss-type: guide-bush switchable + 0.1 µm resolution.
Tolerances held: milling ±0.003 mm, turning ±0.002 mm, grinding and wire EDM ±0.002 mm. Capability: Ppk >= 1.67 initial and Cpk >= 1.33 in production on key characteristics.
Certifications: ISO 9001:2015 (116024/A/0001/UK/En), IATF 16949:2016 (131941/A/0001/SM/En, clause 8.3 design excluded, disclosed openly) and ISO 14001:2015 (116024/B/0001/UK/En), issued to Dongguan Zhuohang Ltd, USCC 91441900MA4UWT6X39, established 2005.
Service area: Austria, Belgium, the Czech Republic, Denmark, France, Germany, Greece, Hungary, Ireland, Italy, the Netherlands, Spain, Sweden and the United Kingdom in Europe; Brazil, Canada, Mexico and the United States in the Americas; China, Israel, Japan, Singapore and Sri Lanka in Asia; Australia and New Zealand in Oceania; and South Africa in Africa — built in China, shipped worldwide.
Contact: Felipe Iglesias, [email protected], +86 13126536955.
Send your drawing for a quote.
Email [email protected] or call +86 13126536955 for a review and quote.
Frequently Asked Questions
Which CNC machining services do you provide?
We provide 3-axis, 4-axis, and 5-axis CNC milling, CNC turning, single-setup mill-turn, and precision grinding, plus deburring, tapping, laser marking, and assembly — all run in-house on over a hundred machines.
How does volume affect process choice?
At low volume you minimize setups; at high volume you optimize cycle time and yield. The same geometry can call for different processes at different volumes, and the review decides the trade-off honestly.
When is 5-axis worth it?
When a part has features on multiple faces that must be related, a 5-axis setup removes re-fixturing. At volume that saving repeats on every unit and improves accuracy by removing alignment error.
What tolerances do your services hold?
In short, ±0.003 mm on CNC milling, ±0.002 mm on CNC turning, and ±0.002 mm for precision grinding. We verify critical dimensions on Hexagon CMMs, with process capability Ppk ≥ 1.67 at the initial study on key characteristics and Cpk ≥ 1.33 on general characteristics.
What is your minimum order quantity and lead time?
Roughly 3, 7, or 30 days depending on part complexity and process steps. Simpler parts ship in about 3 days; parts with surface finishing or many operations fall into the longer 30-day tier.
Which tolerances does each service hold?
In short, Milling and turning hold ±0.003 mm (milling) / ±0.002 mm (turning) as standard, and precision grinding reaches ±0.002 mm. The cost sits in the step between the two, because a dimension that forces grinding adds a process and an inspection on every part.
How do surface finishes add cost as volume grows?
In short, A finish is a per-part cost, invisible at one piece and significant at ten thousand. Standard machining leaves around Ra 3.2 µm, fine milling or light grinding reach Ra 1.6 µm, and precision grinding reaches Ra 0.8 µm, so the finish should be specified only where the function needs it.
How do I get a machining service quote?
Email your STEP, IGES, or 2D drawing to [email protected] with the order quantity and annual volume. We return a review and a quote matched to your volume, usually within one business day.
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Standards referenced on this page
- ASTM A582/A582M-12 — Standard Specification for Free-Machining Stainless Steel Bars
- ISO 9001 — Quality management systems — Requirements
- ASTM E8/E8M-21 — Standard Test Methods for Tension Testing of Metallic Materials