Sourcing Mechanical Assembly in China
What an industrial buyer needs to know before requesting quotations for mechanical assembly from China-based suppliers.
Overview
Sourcing mechanical assembly from China is one of the recurring decisions of any industrial buyer who needs to balance unit cost, quality control and lead time. This page collects what an EU buyer should know before opening a Request for Quotation for mechanical assembly suppliers in China: typical materials, tolerances expected on the drawing, certifications worth asking for, current price positioning and shipping turnaround.
From a pure cost angle, China prices mechanical assembly roughly 40–60% lower compared to the average European baseline. Real numbers depend on volume, alloy and surface treatment, but this gap is what justifies a sourcing exercise toward China in the first place. Cost is rarely the only variable: lead time, audit access, certifications and supplier capacity at the right volume usually decide which suppliers actually make the shortlist.
A typical first article from a China-based mechanical assembly shop takes 10–30 working days, plus 25–40 shipping days of shipping to central Europe. Series production lead time depends on volume and capacity reservation: most established shops want a forecast horizon of 60 to 90 days to plan raw materials and surface treatment subcontractors.
When to choose this process
Use when assembly is repetitive, well-documented (BOM + work instructions) and free of certified processes the OEM must keep in-house.
Outsourced assembly bundles component sourcing, assembly, leak/test/calibration and shipping. The cost saving comes from labour arbitrage and from removing the buyer's in-house assembly footprint.
Why source here — China
- Lowest unit cost on high-volume programmes
- Vertically integrated supply chains (raw to packaged)
- Tooling-friendly: moulds and dies at 50–70% EU cost
- Mature export logistics, FOB/CIF/DAP all standard
What to watch out for
- Sea freight 25–40 days; air freight at 5–10× cost
- IP risk — use NNN agreements, fragment the BOM if critical
- QA dispersion: third-party inspection (SGS/BV/AsiaInspection) is mandatory
Typical materials
- Buy-to-print parts + commercial components (fasteners, seals, bearings, motors)
Typical tolerances
Defined by test/calibration spec: leak rate, torque, electrical continuity, run-in cycle.
Certifications to ask for
- ISO 9001
- IATF 16949 (auto)
- ISO 13485 (medical)
- UL/CE for finished units
- IATF 16949
- EN 9100
- RoHS, REACH on demand
Frequently asked questions
Is it worth sourcing mechanical assembly from China?
It pays off when the lower hourly rate (40–60% lower) beats the logistic friction (25–40 shipping days) and the selected supplier holds the required certifications (ISO 9001, IATF 16949). Below ~200 pcs/year it often doesn't; above ~1,000 pcs/year the math almost always tips in favour.
How do I structure an assembly contract?
Define BOM ownership (consigned vs supplier-bought), tests/calibrations, packaging spec, and split-of-warranty between assembler and OEM.
Will Chinese tariffs/anti-dumping hit my part?
Check the EU TARIC code: anti-dumping on screws, steel pipes, aluminium wheels and many casts is in force. A licensed forwarder can pre-screen for free.
Other countries
Other processes
Editorial market guide. Supplyria is a marketplace; we don't list private suppliers on this page. Cost ranges and lead times are indicative and based on public industry benchmarks.