- 100+ machines including 20+ 5-axis centres; 100+ staff, 80%+ skilled technicians.
- Exports to 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 — based in China, serving customers worldwide.
- 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 makes a CNC precision machining enquiry quotable?
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 to confirm before the order
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 cheaper to settle at quote time than once parts already exist, because the changes are usually trivial on the drawing and significant on the machine.
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, agreed per feature during quoting.
Which legal entity is actually responsible for the work?
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 to confirm on your side
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.
What capacity sits behind this?
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 a floor of 100-plus 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.
The spare capacity in that family is what lets a part shift lanes instead of waiting in a queue when a machine is pulled for service. That, not the headline machine, is what protects a delivery date.
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.
The three-stage buyer's checklist — RFQ, in-process, and incoming
A CNC machining buyer's checklist is not a single document; it is three checklists at three stages of the job, each catching a different class of problem. The RFQ checklist catches drawing and specification issues before the quote is written. The in-process checklist catches process and quality issues during the run. The incoming checklist catches tolerance, finish, and documentation issues when the parts arrive. If you run all three, you are the one whose parts arrive right the first time; if you run only the first, you are the one who catches problems in inspection and pays for them in rework.
Stage 1 — RFQ checklist (before the quote is written). 3D model and 2D drawing both attached; material called out by grade and temper (6061-T6, not "aluminum"); three tightest tolerances identified; surface finish, coating, and which faces specified; quantity, target date, and FAI/PPAP requirement stated; datum scheme explicit on the drawing; internal corners filleted (no sharp corners from end mills); walls above minimum (0.5 mm aluminum, 0.8 mm steel); hole depths within 4× diameter for twist drilling.
Stage 2 — In-process checklist (during the run). First-article inspection report received and signed off; SPC sampling rate agreed and running (5/100 for critical, 1/100 for non-critical); Cpk reported on key characteristics (≥ 1.33 in production, ≥ 1.67 initial); tool wear monitored and replaced at the prescribed life; material certs and heat-lot traceability received with the parts, not after; inspection temperature reported alongside the CMM result on parts above 200 mm or below ±0.01 mm.
Stage 3 — Incoming checklist (when the parts arrive). Sample inspection against the FAI report (5-10 parts at random, measure three tightest tolerances); surface finish measured with a profilometer, not eyeballed; material cert and heat-lot match the parts; coating thickness and type verified with a gauge; packaging damage and moisture inspection; documentation package complete (FAI report, Cpk report, material certs, heat-lot traceability, CMM report, PPAP for automotive, AS9100 first-article for aerospace).
The three checklists catch every class of problem a CNC machining job can produce: specification issues in the RFQ, process issues during the run, and verification issues at incoming. If you run all three, you are the one whose parts arrive right the first time and whose second shipment arrives right the second time. If you run only the first, you are the one who catches problems in assembly, in field return, or in the customer's complaint, and pays for them at the most expensive point in the chain.
Common RFQ pitfalls and how to avoid them
The RFQ is where 80 percent of sourcing delays and 60 percent of cost overruns originate. The common pitfalls are not exotic; they are the same five mistakes buyers make repeatedly, and each has a simple fix that takes minutes on the drawing before the RFQ goes out.
Pitfall 1: Sending only a 3D model, no 2D drawing. The 3D model carries geometry but not tolerance, surface, or datum. The shop is forced to assume "ISO 2768 medium" on every dimension and "as-machined" on every surface, both of which are usually wrong. Fix: send a 2D drawing with tolerances called out on the dimensions that matter, surfaces specified on the faces that mate, and a datum scheme that matches the assembly. The drawing takes 30 minutes to produce and saves a week of back-and-forth.
Pitfall 2: Calling out "aluminum" instead of "6061-T6." Aluminum has dozens of alloys with machinability and price differences of 2-3×. The shop assumes 6061-T6 by default, but if the buyer meant 7075-T6 (higher strength, harder to machine, 2× the price), the quote is wrong and the parts are wrong. Fix: state the alloy and temper on the RFQ. If you are unsure, ask the shop which alloy fits the application and quote both.
Pitfall 3: Calling out ±0.003 mm on every dimension. A drawing with every dimension at ±0.003 mm forces the shop to treat every feature as critical, which adds inspection time and scrap risk to every dimension. The cost doubles or triples versus a drawing with ±0.003 mm on the three mating features and ±0.1 mm on the rest. Fix: tighten only the surfaces that mate or seal; leave the rest at ISO 2768 medium. The shop will quote the tight features with the right inspection and the loose features with fast inspection, and the unit price drops by 30-50 percent.
Pitfall 4: Not specifying the surface finish. "Smooth" is not a surface finish; "Ra 0.8 µm" is. A part with Ra 0.8 µm requires grinding or lapping after milling; a part with Ra 3.2 µm is standard milling finish. The cost difference is 20-100 percent. Fix: call out the Ra on mating and sealing surfaces and specify the coating (Type II sulfuric anodize, Type III hardcoat, electroless nickel) and color on the external surfaces.
Pitfall 5: Not specifying FAI/PPAP requirement. First-article inspection is standard on tight-tolerance parts; PPAP is mandatory on automotive parts and any part going into a regulated industry. A shop that quotes without knowing the documentation requirement is quoting blind on the documentation cost, which can be $200-2,000 per part on PPAP-level work. Fix: state the FAI/PPAP requirement on the RFQ. The shop will quote the documentation as a separate line, and you see the cost before the order is placed.
The five pitfalls above catch 80 percent of sourcing delays. If you run the checklist, fix the pitfalls, and send a clean RFQ, you get a quote in 24 hours and a part that meets the drawing. If you send a 3D model with "aluminum" and "smooth", you get a quote in a week and a part that misses the intent.
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
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.
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 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.
What happens if the first article does not conform?
In short, The nonconformance is documented and the corrective action is agreed before any further parts are made. Whether the replacement cost sits with the plant or the customer depends on where the deviation came from, which is why the revision and the drawing standard are confirmed in writing at the start.
What is the difference between a prototype build and a production build here?
Usually only quantity and scheduling. Both run on the same machines and the same process, which is what makes a later ramp a scheduling change rather than a re-qualification.
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.
Standards referenced on this page
- ASTM B211/B211M-19 — Standard Specification for Aluminum-Alloy Rolled or Cold Finished Bar, Rod, and Wire
- ASTM A582/A582M-12 — Standard Specification for Free-Machining Stainless Steel Bars
- IATF 16949:2016 — Automotive quality management system standard