Zhuohang Precision Machining FactoryCNC Turning Service

CNC Turning Service Dfm Checklist

CNC turning workshop, Zhuohang Precision Machining Factory, Dongguan, China

CNC Turning Service Dfm Checklist — A practical checklist for cnc turning service — the information that makes a quote accurate, and the gaps that make it. Tolerances: ±0.002 mm turning, ±0.003 mm milling — ISO 9001 / IATF 16949 verified.

A practical checklist for cnc turning service — the information that makes a quote accurate, and the gaps that make it guesswork.

The gist
  • Build-to-print work: the plant cuts to your design and reports against your drawing.
  • 6,800 m² across two buildings in Hengli Town, Dongguan. Production, inspection, and engineering under one roof.
  • A quote is only as good as the drawing behind it.
  • The four omissions that turn an accurate quote into a revised one.
  • Confirm revision, FAIR scope, and delivery terms in writing before release.

What to include with a CNC turning service drawing

A quote is only as good as the drawing behind it. The gap between a fast quote and an accurate one is almost always a missing tolerance scheme, an unspecified surface finish, or a material callout that names a family rather than a grade.

The five things that change the answer: the 3D model, the 2D drawing with tolerances, the material grade, the quantity (and the anticipated repeat quantity), and any inspection or certification requirement.

What is the certification position?

ISO 9001:2015, IATF 16949:2016 (excluding clause 8.3 product design), and ISO 14001:2015. Each with a certificate number verifiable with the registrar.

Pre-enquiry checklist

These are the items whose absence most often produces a quote that changes after review.

  • 3D model in STEP or IGES, plus a 2D drawing — the drawing carries the tolerances the model does not.
  • Material as a grade, not a family. "stainless" is not a specification; 316L is.
  • Tolerance per feature, not a blanket note. A single tight dimension drives cost more than ten loose ones.
  • Surface finish callouts where they matter, with the standard named (Ra in ISO or ASME).
  • Quantity and expected repeat quantity — these are different numbers and they change the process.

Pre-release verification

Before releasing, these are the items worth confirming in writing.

  • Which drawing revision is being built. in writing, on the order acknowledgement.
  • What the first-article report will contain, and whether it is full inspection or a sample plan.
  • How capability is reported, the index, the stage, and the sigma estimator, named.
  • Who owns an engineering change and how it is documented mid-run.
  • Packaging, duty, and freight responsibility — whether the quote is EXW, FOB, or delivered.

Three things that change the price without changing the part

Three design decisions drive most of the cost on a machined part: internal corner radii matched to a real cutter diameter, cavity depth kept within about four times the tool diameter, and a general tolerance on every feature that does not mate. Each one changes the tool that can be used, and the tool determines how much material can be removed per minute. Which is why these matter more than any process selection.

This is worth raising at quote stage rather than after the first article, because the changes are usually trivial on the drawing and significant on the machine.

How much of the floor is in this family?

Total machine count is not the question — the question is how many machines sit in the family that makes your part, because that is the queue your part waits in. The floor runs over a hundred machines: 50+ three-axis centres for prismatic work, 20+ four-axis, 20+ five-axis, 25+ turning and mill-turn centres, Swiss-type lathes for long slender parts, precision grinding and wire EDM for the tightest features.

Depth in the same family is what lets a part send work to a free machine instead of letting it wait when a machine is pulled for service. That, not the headline machine, is what protects a delivery date.

What tolerance applies?

±0.003 mm on CNC milling, ±0.002 mm on CNC turning; ±0.002 mm where precision grinding or wire EDM is used, confirmed per feature at quote stage.

Who is on the other side of the purchase order?

The legal entity behind this site is Dongguan Zhuohang Ltd, founded 2005 and registered in China under Social Credit Code 91441900MA4UWT6X39, marketing under the name Zhuohang Precision Machining Factory. Its registered and production address is No. 8, Shuibian Songyuan Road, Hengli Town, Dongguan, Guangdong, China 523470.

Use the National Enterprise Credit Information Publicity System and the 18-character code to verify a Chinese manufacturer. Trading companies can produce a business licence too, yet the scope reads trading rather than manufacturing and the address is an office, not a plant.

What this shop actually runs

If you ask for capability evidence, you deserve a specific answer. This facility operates 100+ CNC machines across 6,800 m2 in Dongguan, China, staffed by 100+ people. The machines, listed 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). Set up for 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). Set up for 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). Set up for 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). Set up for shafts, bushings, flanges up to ±0.002 mm.
  • Wire EDM (5+) - Sodick AQ535L (550/350/300 mm travel, ±20° taper, 800 kg workpiece). Set up for 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.

Tolerance bands: ±0.003 mm milled, ±0.002 mm turned, ±0.002 mm ground or wire-cut. Capability indices: Ppk >= 1.67 at the initial study; Cpk >= 1.33 ongoing in production.

Certifications: ISO 9001:2015 (116024/A/0001/UK/En) · IATF 16949:2016 (131941/A/0001/SM/En, design clause 8.3 excluded) · ISO 14001:2015 (116024/B/0001/UK/En), held by Dongguan Zhuohang Ltd (USCC 91441900MA4UWT6X39, since 2005).

Service area: we supply 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, with worldwide delivery from China.

Contact: Felipe Iglesias, [email protected], +86 13126536955.

Get a quote with the cost drivers named

Send your drawing to [email protected] or call +86 13126536955. We will tell you which tolerance or setup is driving the number, not just the number.

Frequently Asked Questions

Can you work to ASME Y14.5 as well as ISO?

Yes. Both geometric dimensioning conventions are used. The important thing is that the drawing states which one applies, because the same symbol can mean different things under the two standards.

How is material traceability maintained?

Incoming stock is checked against the mill certificate — composition by XRF, hardness where specified — and traceability is held per heat or per batch as the certificate defines it.

What is a first-article inspection report?

A documented dimensional report on the first part off the process — typically per AIAG PPAP or a customer-defined format. It is the evidence that the process makes the drawing, and it is worth specifying before the order rather than after.

Are you a manufacturer or a trading company?

A manufacturer. The legal entity is Dongguan Zhuohang Ltd (Registration No. 91441900MA4UWT6X39), operating a 6,800 m² facility with over a hundred machines and 100+ staff in Dongguan. Factory visits are welcome.

What materials do you machine?

Aluminum, stainless steel, titanium, brass, copper, and Inconel for metals; PEEK and Delrin (POM) for plastics. Material certificates are verified on incoming stock.

How is an engineering change handled mid-production?

The change is documented against a revision, the affected parts in process are identified, and the revised drawing is confirmed in writing before work restarts. The important part is that the revision in force at any moment is a single, written one.

Do you need both a model and a drawing?

Yes, in practice. The model defines geometry; the drawing defines what has to be true about that geometry. A quote from a model alone leaves the tolerance scheme to assumption, which is where disputes start.

Standards referenced on this page

  • ASTM A582/A582M-12 — Standard Specification for Free-Machining Stainless Steel Bars
  • ASTM A484/A484M-24 — Standard Specification for General Requirements for Stainless Steel Bars, Billets, and Forgings
  • ISO 9001 — Quality management systems — Requirements