Steel CNC Precision Machining
±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.
Where the money is actually decided
Two specification differences cause most avoidable cost when sourcing from China: the drawing standard (ISO versus ASME Y14.5 — a single symbol is not interpreted identically) and surface finish callouts expressed in different units or parameters. Confirming both in writing at enquiry stage costs nothing and removes a common source of dispute.
This belongs in the quote discussion, not the first-article review, because the changes are usually trivial on the drawing and significant on the machine.
What identifies the legal entity behind the machines?
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.
Four checks to run on any CNC precision machining quote
Whether you buy from this plant or another, these checks separate a real floor from a brochure. None of them require a purchase order.
- Which revision is being quoted, in writing? Ask for it in writing.
- Whether the drawing standard is understood (ISO vs ASME Y14.5)? Ask for it in writing.
- Whether the quote includes duty, freight, and packaging? Ask for it in writing.
- How a nonconforming first article is handled and who pays? Ask for it in writing.
What happens between quote and first article?
Programming and offline verification, fixture design and build, material inward inspection, roughing, finishing, inspection, and the first-article report. Each step has a failure mode, and the fixes that hurt most are the first and last steps. The manufacturability review is where cost is actually decided. A pocket depth reduced by a few millimetres, or an internal corner radius opened from 1 mm to 3 mm, cuts cycle time more than any change of machine, because it changes the tool that can be used.
Carbon steel CNC precision — the workhorse material
Carbon steel is the workhorse of CNC precision, and the grade selection runs on three carbon contents: 1018 (low-carbon, 0.18 percent C, 60 ksi, general-purpose), 1045 (medium-carbon, 0.45 percent C, 90 ksi, shafts and gears), 1095 (high-carbon, 0.95 percent C, 130 ksi, springs and cutting tools). The tolerance: 1018 (free-machining, 70 percent machinability) holds ±0.003 mm on milled, ±0.002 mm on turned, ±0.05 mm on general. 1045 (55 percent machinability) holds 20 percent wider; 1095 (40 percent) holds 40 percent wider. The heat-treatment: 1018 case-hardened (carburized 900-925 °C, quenched, tempered 150-200 °C); 1045 through-hardened (austenitized 820-850 °C, water-quenched, tempered); 1095 through-hardened (austenitized 790-815 °C, oil-quenched, tempered). The cost: 1018 $1-3/kg (cheapest); 1045 $1.50-4; 1095 $2-5.
The shop: Dongguan Zhuohang Ltd (USCC 91441900MA4UWT6X39, established 2005, 6,800 sqm floor, 100+ staff, 100+ machines, Mazak VARIAXIS I-600, INTEGREX I-250H S, TSUGAMI B0206-III, STAR SR-32J Type N, Citizen Cincom A20-3F7, Hexagon CMM with 10:1, 20 ±1 °C inspection room, ISO 9001:2015 116024/A/0001/UK/En, IATF 16949:2016 131941/A/0001/SM/En, ISO 14001:2015 116024/B/0001/UK/En). Tolerance: ±0.003 mm milling, ±0.002 mm turning, Ppk ≥1.67, Cpk ≥1.33. Contact: Felipe Iglesias, +86 13126536955, [email protected], PT/EN/FR/ES/ZH/JP.
Steel surface treatment and post-machining
Steel's surface treatment discipline: (1) black oxide (cosmetic, minimal dimensional change, the standard for indoor); (2) phosphate (corrosion resistance, 0.005-0.010 mm, the standard for outdoor); (3) zinc plate (sacrificial corrosion, 5-15 µm, the standard for fasteners and outdoor hardware); (4) hard chrome (wear resistance, 10-50 µm, the standard for hydraulic cylinders and wear surfaces); (5) nickel plate (cosmetic, 5-15 µm, the standard for decorative); (6) carburize (case-hardened surface, 0.5-2.0 mm depth, the standard for gears and shafts). The dimensional change: black oxide negligible; phosphate 5-10 µm; zinc plate 5-15 µm per side; hard chrome 10-50 µm per side; nickel plate 5-15 µm per side. You should specify the treatment on the RFQ; one that does not is one whose steel ships bare. Post-machining: steel is often stress-relieved (600-650 °C for 1-2 hours) after rough machining, then finish-machined.
The shop: Dongguan Zhuohang Ltd (USCC 91441900MA4UWT6X39, established 2005, 6,800 sqm floor, 100+ staff, 100+ machines, Mazak VARIAXIS I-600, INTEGREX I-250H S, TSUGAMI B0206-III, STAR SR-32J Type N, Citizen Cincom A20-3F7, Hexagon CMM with 10:1, 20 ±1 °C, ISO 9001:2015 116024/A/0001/UK/En, IATF 16949:2016 131941/A/0001/SM/En, ISO 14001:2015 116024/B/0001/UK/En). Tolerance: ±0.003 mm milling, ±0.002 mm turning, Ppk ≥1.67, Cpk ≥1.33. Contact: Felipe Iglesias, +86 13126536955, [email protected], PT/EN/FR/ES/ZH/JP.
Steel heat-treatment and post-machining
Steel's heat-treatment state drives its machinability and final properties, and you should specify the state on the RFQ. The three states for 1045: annealed (the standard delivery state, 90 ksi tensile, 75 percent machinability); normalized (austenitized at 820-850 °C, air-cooled, 95 ksi, 70 percent machinability); quenched and tempered (austenitized, water-quenched, tempered at 200-300 °C for hardness or 400-600 °C for toughness, 110-130 ksi, 50-60 percent machinability). The machinability: annealed is 75 percent rating; normalized is 70 percent; Q&T is 50-60 percent (the harder state wears the tool faster). The tolerance decision: 1018 holds ±0.003 mm on milled, ±0.002 mm on turned, ±0.05 mm on general.
The shop: Dongguan Zhuohang Ltd (USCC 91441900MA4UWT6X39, established 2005, 6,800 sqm, 100+ staff, 100+ machines, Mazak VARIAXIS I-600, INTEGREX I-250H S, TSUGAMI B0206-III, STAR SR-32J Type N, Citizen Cincom A20-3F7, Hexagon CMM 10:1, 20 ±1 °C, ISO 9001:2015 116024/A/0001/UK/En, IATF 16949:2016 131941/A/0001/SM/En, ISO 14001:2015 116024/B/0001/UK/En). Tolerance ±0.003 mm milling, ±0.002 mm turning, Ppk ≥1.67, Cpk ≥1.33. Felipe Iglesias +86 13126536955 [email protected] PT/EN/FR/ES/ZH/JP.
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). Intended 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). Intended 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). Intended 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). Intended for shafts, bushings, flanges up to ±0.002 mm.
- Wire EDM (5+) - Sodick AQ535L (550/350/300 mm travel, ±20° taper, 800 kg workpiece). Intended 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
What tolerances can you hold?
In short, ±0.003 mm on CNC milling, ±0.002 mm on CNC turning, and ±0.002 mm where precision grinding or wire EDM is used. The achievable tolerance depends on geometry, material, and datum structure, so it is confirmed per feature at quote stage rather than assumed from a headline number.
Which markets do you export to?
In short, 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. Our service area also spans Europe, the Americas, Asia, Oceania and Africa — based in China, we serve customers worldwide.
What is the minimum order quantity for cnc precision machining?
There is no minimum. Prototype quantities are run on the same machines as production quantities, which is what makes a later ramp a schedule question rather than a re-qualification.
Do you sign NDAs before reviewing drawings?
Yes. Sign an NDA before files are exchanged; drawings are kept in the quoting system, not circulated by email.
Is inspection documentation included in the quote?
It should be stated explicitly. A first-article report is a document someone has to produce, and whether it is a full dimensional report or a sample plan changes both the cost and what you receive.
How are parts packed for export?
Each part is packed to spec — finished surfaces individually bagged and boxed, steel given corrosion protection. Packing belongs in the quote: it affects the cost and the condition the parts arrive in.
Can I audit the factory before placing an order?
Yes. On-site visits and video audits are welcome at No. 8, Shuibian Songyuan Road, Hengli Town, Dongguan, Guangdong, China 523470.
Standards referenced on this page
- ASTM A36/A36M-19 — Standard Specification for Carbon Structural Steel
- ASTM B209/B209M-21 — Standard Specification for Aluminum-Alloy Sheet and Plate
- ISO 9001 — Quality management systems — Requirements