- Manufacturing to your print: 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.
- Most machining cost is decided in the CAD file, not on the machine.
- The five DFM rules that move cycle time most: corner radii, cavity depth, wall thickness, functional-only tolerances, and a clean datum structure.
- A DFM review before release is the cheapest engineering you will ever buy.
What design for manufacture means on a 3-axis part
On a 3-axis machine the cutter approaches from above, so every DFM rule reduces to one question: can a real tool reach the feature, and can it do so stiffly? A feature that needs a tiny, long tool is slow and inaccurate; a feature a standard tool can take in a few passes is cheap. The drawing decisions that decide this are few and predictable, which is what makes DFM on machined parts so repeatable.
The DFM checklist — geometry
Walk the part against these. Each line says why it moves cost or risk.
- Internal corner radius ≥ the smallest cutter you can justify. Why: a sharp internal corner forces a smaller tool and many more passes; opening a 1 mm radius to 3 mm can cut cycle time more than changing the machine.
- Cavity depth ≤ ~3–4× the tool diameter. Why: deeper than that, the tool gets long, flexible, and slow, and chatter sets the finish. Shallow, open pockets are dramatically cheaper.
- Wall thickness ≥ ~0.8–1.0 mm on small parts, more on large. Why: thin walls chatter and deflect under the cut; they also distort when released from the fixture.
- Standard hole sizes and depths. Why: drills and taps come in standard series; a non-standard size means a special tool or a reamed hole, both slower.
- Threads called out as a standard series (M, UNC/UNF).strong> Why: a standard thread uses a standard tap or thread mill; a custom pitch needs a custom tool.
- Features accessible from the setups you have. Why: a side-wall feature at an angle to the table needs an extra setup or a rotary axis; designing it perpendicular to a face keeps it on one setup.
The DFM checklist — tolerances and datums
Tolerance is where drawings quietly overspend. These keep it under control.
- Tolerance only the features that mate or function. Why: every tight dimension is a measurement and a risk; a general ±0.1 with three ±0.01 callouts is cheaper and performs identically.
- One primary datum, with others chaining from it. Why: re-referencing mid-part multiplies inspection and fixturing and invites stack-up error.
- Surface finish named with its standard (Ra in ISO or ASME). Why: an unnamed finish invites a different result; a finish tighter than function adds a secondary operation.
- Avoid tolerancing to a theoretical sharp edge. Why: a break-edge or chamfer note is cheaper than holding a knife edge that cannot be held.
Common DFM mistakes
The most expensive DFM habit is the blanket tolerance — "all dimensions ±0.01" on a part that only needs three features tight. It forces tight process control and full inspection on every dimension, adds cost where none was needed, and slows the first article. The second is the deep, narrow pocket with a sharp internal corner: it combines the two worst drivers — a long flexible tool and many passes — into one feature. Open the corner and shallow the pocket and the same part can come off in a fraction of the time.
The third is designing a feature that needs an extra setup without realising it. A hole on a side wall looks trivial in CAD and costs a whole re-fixturing on the floor. Ask, at the CAD stage, "which face does the cutter see this from?" — if the answer is "another setup," reconsider the geometry.
What to send for an accurate quote
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. The model alone leaves the tolerance scheme to assumption, and that is where disputes start.
What to confirm before you release production
- 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.
Where the money is actually decided
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.
What the certificates actually cover
Three certificates, each with a number you can check with the registrar:
| Standard | Certificate number | Scope note |
|---|---|---|
| ISO 9001:2015 | 116024/A/0001/UK/En | Quality management system |
| IATF 16949:2016 | 131941/A/0001/SM/En | Automotive QMS — excludes clause 8.3 product design |
| ISO 14001:2015 | 116024/B/0001/UK/En | Environmental management system |
The IATF 16949 certificate excludes clause 8.3 (product design). That is normal for a build-to-print manufacturer and it is stated here rather than left for an auditor to discover: we cut to the drawings you provide, it does not originate the design.
What tolerance applies?
±0.003 mm on CNC milling and ±0.002 mm on CNC turning; ±0.002 mm where precision grinding or wire EDM is used, set feature by feature when we quote.
Which entity is responsible for the work?
Dongguan Zhuohang Ltd, Registration No. 91441900MA4UWT6X39, in operation since 2005.
What this shop actually runs
Capability evidence should come as specifics, not slogans. Behind this guide is a 6,800 m2 plant in Dongguan, China running 100+ CNC machines 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). Cut on 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). Cut on 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). Cut on 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). Cut on shafts, bushings, flanges up to ±0.002 mm.
- Wire EDM (5+) - Sodick AQ535L (550/350/300 mm travel, ±20° taper, 800 kg workpiece). Cut on 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: ±0.003 mm CNC milling / ±0.002 mm CNC turning / ±0.002 mm grinding and wire EDM. Capability: Ppk >= 1.67 initial on key characteristics, Cpk >= 1.33 ongoing.
Certificates: ISO 9001:2015 (116024/A/0001/UK/En), IATF 16949:2016 (131941/A/0001/SM/En, with design clause 8.3 excluded, stated openly) and ISO 14001:2015 (116024/B/0001/UK/En), issued to Dongguan Zhuohang Ltd, registration 91441900MA4UWT6X39, founded 2005.
Where we ship: 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 — plus other countries and regions worldwide, shipped from our base in Dongguan, China.
Contact: Felipe Iglesias, [email protected], +86 13126536955.
Get a DFM read before you release
Send your drawing to [email protected] or call +86 13126536955. We will tell you which corner radius or pocket depth is driving cycle time, not just the price.
Frequently Asked Questions
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.
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 more than 100 machines and 100+ staff in Dongguan. Factory visits are welcome.
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.
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.
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.
Do you hold stock or consignment for repeat orders?
Repeat orders can run against a forecast so stock and, where the part warrants it, dedicated fixturing are held ready. This is a commercial arrangement, not a standard term, so raise it at the second order rather than the first.
Continue reading: 3 Axis CNC Machining Checklist · 4 Axis CNC Machining
Standards referenced on this page
- ASTM A582/A582M-12 — Standard Specification for Free-Machining Stainless Steel Bars
- ISO 14001 — Environmental management systems — Requirements with guidance for use
- IATF 16949:2016 — Automotive quality management system standard