A Taiwanese machine shop can usually hold the tolerance you need. What stalls most first orders is not capability but the gap between what the drawing says and what the buyer actually meant: a general tolerance class that was never written down, a plating spec with no thickness, a material grade named in one country’s standard and stocked in another’s. Each gap becomes a question, a delay or an assumption made on the shop floor, and the assumption is the one that shows up at incoming inspection.
💬 Sending machined-part drawings to Taiwan and want the RFQ package, the shortlist and the inspection plan handled in one place? We find, vet and manage the shop that fits each part as part of sourcing from across Asia. Send us the drawings. How we work there: our sourcing agent service for Taiwan.
This article is about the machining job itself. How to find and check a Taiwanese company, the BSMI question and the certificate of origin are covered in sourcing from Taiwan: a buyer’s step-by-step guide, and the factory search across the region in finding factories in ASEAN and Taiwan.
What a machine shop needs before it can quote properly
Send a complete RFQ package — 3D model, fully dimensioned 2D drawing, quantities per release, and the inspection documents you expect — because a quotation built on a model alone is a quotation for a different part.
A 3D model tells the shop the nominal geometry. It does not tell it which dimensions are critical, which surfaces are functional, or how the part will be measured. A shop that receives only a STEP file will price to its own default tolerances and its own default inspection, and the comparison between two shops becomes meaningless because each has quoted a different level of control.
| Item in the RFQ package | What happens when it is missing |
|---|---|
| 2D drawing with revision letter, matched to the 3D model | The shop quotes from the model; later revisions cannot be traced to a price |
| General tolerance class (e.g. ISO 2768-m or -f) stated in the title block | Untoleranced dimensions are held to the shop’s own habit |
| Critical dimensions marked (balloons or a “key characteristic” symbol) | Every dimension is inspected the same way, or none of them is |
| Material grade with the standard named (EN, ASTM, JIS, CNS) | An “equivalent” grade is substituted without anyone deciding it is equivalent |
| Surface treatment with spec, thickness and colour | Anodising or plating is quoted to the cheapest version the finisher offers |
| Quantity per release and expected annual volume | Set-up cost is spread over the wrong batch size |
| Inspection documents required with the first shipment | The shop does not budget CMM time and charges for it later |
The parts of a drawing that cause most questions
Most clarification requests come from the same five areas: the general tolerance note, datums, surface finish, threads and edge treatment, and the material and finishing call-outs.
General tolerances. If the title block does not name a general tolerance standard and class, the untoleranced dimensions have no agreed limit. ISO 2768 is the general standard most shops recognise; state the class rather than leaving it to a default.
Datums and GD&T. A position tolerance without a clear datum reference frame forces the shop to choose how to fixture and measure the part. Two shops can then measure the same part and both be “right”. If the part depends on geometric tolerancing, say which standard the drawing follows (ISO GPS or ASME Y14.5), because the two do not always read the same symbol the same way.
Surface finish. “Ra 0.8” on a face is clear. A general roughness note with no value, or a roughness symbol without a unit system, is not. Say whether the value applies before or after coating.
Threads and edges. Thread class, thread depth versus drill depth, and “break all sharp edges” without a size are frequent sources of rejected parts that are, strictly, within drawing.
Material and finishing. Name the grade and the standard it comes from. Where the shop proposes a local equivalent, ask for the proposal in writing with the chemical and mechanical values side by side, and approve it on the drawing revision rather than in an email thread.
None of this is specific to Taiwan — it is what any machine shop needs. The Taiwan-specific point is practical: you will usually be communicating across a language and a time-zone gap, so a question that takes ten minutes at a local shop takes a day. The clearer the package, the fewer of those days the job consumes.
Outside processes: heat treatment, plating and anodising
Ask which operations the shop performs in-house and which it sends to a sub-supplier, because the certificate for a heat-treated or plated part is issued by whoever did the process, not by the machine shop.
Many precision machining shops anywhere in the world subcontract heat treatment, plating, anodising, passivation or painting to specialist finishers nearby. That is a normal and often sensible arrangement. It becomes a problem only when the buyer does not know about it, because:
- the hardness report or coating-thickness report has to come from the finisher, through the machine shop;
- a change of finisher is a process change that can alter the result, even if the machine shop and the drawing stay the same;
- a delay at the finisher is a delay on your order, and the machine shop may not see it coming.
Put two lines in the purchase terms: the shop names its sub-suppliers for special processes, and it does not change them without notice. Ask for the finisher’s report to travel with each lot.
💬 Not sure which reports to ask a Taiwanese shop for, or how to word the sub-supplier clause? Tell us about the part and the processes, and we will set out the inspection plan before the first order.
Inspection documents: what to ask for, and at which stage
Ask for a first article inspection report against a ballooned drawing on the first lot, material certificates on every heat or batch of material, and process reports for each special process — then reduce the dimensional report to critical dimensions once the process is proven.
| Document | When | What it should show |
|---|---|---|
| First article inspection (FAI) report | First production lot, and after any drawing or process change | Every dimension on the ballooned drawing, nominal, tolerance, measured value and method |
| Dimensional report for critical characteristics | Every lot after the FAI is approved | The marked critical dimensions, sample size agreed in advance |
| Material certificate (mill certificate) | Every heat or batch of raw material | Grade, standard, chemical composition, mechanical properties, heat number traceable to the parts; specify the type you need, e.g. an EN 10204 3.1 inspection certificate |
| Heat treatment report | Every heat-treated lot | Process, hardness results and where they were measured |
| Coating / plating report | Every finished lot | Thickness measurement, and any adhesion or salt-spray test the drawing requires |
| Certificate of conformity | Every shipment | Part number, revision, quantity, lot reference, statement of conformity to the drawing |
Agree the sample size and measurement method before the first lot. “Inspect critical dimensions” with no sample size is not an inspection plan; it is a hope. For how pre-shipment inspection by sampling works in practice, see pre-shipment inspection and AQL — the method is the same wherever the factory is.
Who owns the drawings, programs and fixtures
Your drawing stays yours, but the shop’s own manufacturing drawings, CNC programs and fixtures are a separate question, and under Taiwan’s Copyright Act a commissioned work belongs to the person who made it unless the contract says otherwise.
Article 12 of Taiwan’s Copyright Act makes the commissioned party the author of a work completed under commission, unless the agreement names the commissioning party as author; where the economic rights stay with the commissioned party, the commissioning party may still use the work. Checked against the Laws and Regulations Database of the Republic of China (Taiwan) on 17 October 2026.
For a machining job this matters in a narrow but real way. If you pay for dedicated fixtures, gauges or a re-drawn manufacturing drawing, decide in the purchase terms whether you own them, whether the shop may use them for anyone else, and whether they are released to you if you move the part. The broader design-ownership question — schematics, firmware, a design the factory developed for you — is covered in Taiwan electronics OEM and ODM.
Export control and duty: check, do not assume
Two questions sit outside the machine shop: whether the part falls under Taiwan’s strategic high-tech commodities (SHTC) controls, and what duty applies at destination — answer both before the first shipment, not after.
Taiwan controls the export of strategic high-tech commodities under its Foreign Trade Act and the Regulations Governing the Export and Import of Strategic High-tech Commodities. Whether an item is controlled depends on its technical specification against the control list, and on its end use and end user — not on what the part is called or its HS code. An ordinary bracket is unlikely to meet a controlled specification, but precision components for certain machinery, aerospace or semiconductor equipment can. How the permit system works is set out in Taiwan electronics OEM and ODM.
On duty: Taiwan has no preferential trade agreement with Vietnam and is outside RCEP. Build the ordinary rate into the landed cost — see importing into Vietnam from Thailand, Malaysia or Taiwan and comparing Asian suppliers on landed cost.
A working sequence for the first order
Fix the drawing, then the shortlist, then the inspection plan, then a first article — in that order.
- Complete the RFQ package: model, drawing at a stated revision, general tolerance class, critical dimensions, material and finishing specs, quantities.
- Shortlist and check the shops — see finding factories in ASEAN and Taiwan.
- Compare quotations line by line: same revision, same inspection scope, same finishing spec.
- Agree the inspection documents and sample sizes in the purchase terms, plus the sub-supplier clause and fixture ownership.
- Order a first article lot, review the FAI report against the ballooned drawing, and approve it in writing at that revision.
- Release production, with critical-dimension reports and material certificates on each lot.
If the part is still changing, it belongs in a prototype phase first — see prototyping and low-volume manufacturing in Taiwan.
💬 Want one team to handle the drawing review, the shop shortlist, the FAI approval and the shipment from Taiwan? Start with your drawings and volumes.
Frequently asked questions
1. Can I send only a 3D model to a Taiwanese machine shop for a quotation?
You can, but the quotation will be built on the shop’s default tolerances and inspection. Send a 2D drawing with a stated general tolerance class, critical dimensions and finishing specs if you want quotations you can compare.
2. What is a first article inspection report?
A dimensional report on the first production parts, measured against every dimension on a ballooned drawing. Ask for it on the first lot and again after any change to the drawing, the material or the process.
3. Should I ask for a material certificate on every order?
Ask for one for every heat or batch of material used, with the heat number traceable to your parts. Specify the certificate type you need, for example an EN 10204 3.1 inspection certificate.
4. Who owns the fixtures and CNC programs the shop makes for my part?
Write it into the purchase terms. Under Taiwan’s Copyright Act, a commissioned work belongs to the person who made it unless the agreement says otherwise, so silence does not favour the buyer.
5. Do machined parts from Taiwan need an export permit?
Only if the part meets a specification on Taiwan’s strategic high-tech commodities control list, or the end use or end user raises a military concern. The test is the specification, so check it rather than assume either way.
Sources: Laws and Regulations Database of the Republic of China (Taiwan), Copyright Act (Article 12) and Regulations Governing the Export and Import of Strategic High-tech Commodities (last amended 31 October 2023); International Trade Administration, Ministry of Economic Affairs, SHTC guidance on trade.gov.tw. Checked on 17 October 2026.