Frequently asked questions

There is no fixed minimum order quantity. Prototypes and small batches are accepted, from a few dozen pieces upward. Annual production capacity is approximately 50,000 pieces, so both prototype quantities and repeat production volumes sit comfortably within it.

Email a 2D or 3D drawing to evelyn_lin@machiningservice.cn with the material, the tolerances that matter, the quantity and any surface finish requirement. Quotations are returned within 1–2 working days for complete drawings, and a design-for-manufacturing review is included at no cost. See what to include in a request.

3D models in STEP, IGES or Parasolid (X_T) format, and 2D drawings as PDF or DWG. A 3D model alone is usually enough for simple parts. For anything with critical fits, send both — the tolerance and datum scheme live on the 2D drawing, and without it the machining route has to be guessed.

Yes. Parts can be reverse-engineered from a physical sample where no drawing exists. A drawing-first route is preferred for anything with critical fits, because it allows tolerance stack-up to be reviewed before any material is cut.

No, a DFM review is included with every quotation at no cost. It looks at wall thickness, tool access, internal corner radii, the datum scheme and whether the specified tolerance can be held on the specified feature, and it flags any change worth making before production starts. See the DFM checklist.

Yes. Ask for an NDA before drawings are shared and one is put in place first. Drawings are not shared with third parties, and any subcontracted operation is placed under the same confidentiality requirement.

0.1 mm, 0.01 mm and 0.001 mm, depending on the feature and the process. Turning and milling on aluminium, brass and stainless steel routinely hold 0.01 mm. Bearing bores and sealing faces can be held to 0.001 mm with grinding, or 0.002 mm with wire EDM. Full table on the quality page.

Mark the dimensions the assembly depends on: fits, bore centres, sealing faces, mating surfaces and anything that must interchange with a part from another supplier. Those dimensions are then planned into the process route and reported explicitly on the inspection report, instead of being left under a general tolerance note.

0.5 mm is achievable on a well-supported feature, but thin walls deflect under cutting force and vibrate, which affects both tolerance and surface finish. As a practical guide, keep machined walls at 0.8 mm or above in aluminium and 1.0 mm or above in steel unless the feature is short and fully supported.

A machined internal corner cannot be sharper than the radius of the cutter that reaches it. Specifying a larger corner radius lets a larger, more rigid cutter be used, which cuts faster and holds tolerance better. As a rule, specify at least 1 mm, and in deep pockets at least one sixth of the pocket depth.

Yes, surface finish can be specified as an Ra value. Normal milling and turning produce around Ra 1.6 µm; fine finishing and grinding reach Ra 0.4 µm or better. State the Ra value on the drawing and it will be planned into the process route, since achieving it may add a finishing operation.

Aluminium (AL6061, AL6063, AL7075, AL2024, AL5052), stainless steel (SS303, SS304, SS316), brass (HPb59-1, CuZn39Pb1/2/3, CuZn40, C36000, C37710), bronze (C51000, C52100, C54400), carbon steel (Q235, 20#, 45#), titanium (Grade 2, Grade 5) and engineering plastics and composites including POM, PEEK, nylon, oiled nylon and carbon fibre. Full detail on the materials page.

AL6061 for most parts: good strength, excellent corrosion resistance, predictable machining and good anodising response. AL7075 is specified when strength is the binding constraint, AL5052 for sheet components that need forming, and AL6063 where a high-quality anodised cosmetic surface matters most.

SS316 contains molybdenum, which gives it resistance to chlorides and marine environments; SS304 does not. Choose SS316 for salt water, de-icing salts or chloride-bearing process chemistry. For indoor, freshwater or general industrial use, SS304 is sufficient and less expensive. Where welding is not required, SS303 machines far more easily than either.

Anodising, hard anodising, sand blasting, annealing, polishing, heat treatment, zinc plating, chrome plating, powder coating and painting. Finish certificates for outsourced processes are supplied with the shipment. See finishes by material.

100% of production parts are inspected before shipment, including full visual inspection against a documented standard inspection procedure. Batch sampling is not used as a substitute. Sampling applies only to incoming material checks, where the mill certificate already provides lot-level evidence.

Yes, both are supplied as standard with every shipment. The dimensional inspection report gives measured values against the dimensions specified on the drawing, and the material certificate gives the chemistry and mechanical values for the heat or lot used. First article inspection records are provided for new parts.

Parts that fail inspection are quarantined and never shipped. The deviation is measured and documented, the affected lot is traced back to its material lot, and you are told the measured values and the number of parts affected before any disposition decision is taken. Rework, replacement or acceptance as-is is agreed in writing, and the process cause is corrected and verified before the run resumes. See out-of-tolerance handling.

Buyers may nominate an inspection agency, and factory visits are accepted. Confirm the requirement at quotation so it can be scheduled into the inspection plan rather than added after the parts have been made.

The company operates a documented quality management system, and ISO 9001 and RoHS are recorded on its Made-in-China storefront. Certificate number and certification scope are supplied on request with a quotation. The website states a certification only where it can be evidenced, so the request route is given rather than a badge — see the verification record.

Sample parts are typically delivered in 3–7 working days. Parts requiring special material procurement or an outside finishing process take longer, and the quotation states the lead time for the specific part.

8–30 working days, depending on quantity, material and surface treatment requirements. Finishing processes such as anodising or plating are usually the longest element, so they are quoted as part of the schedule rather than added afterwards.

EXW, FOB, CIF, CNF, DDP and DDU. Parts ship by sea, air or express depending on size, weight and urgency.

T/T, PayPal and Western Union. Payment terms are confirmed with the order.

Poly bag and carton as standard. EPE foam or a wooden case is used for higher-value or fragile parts, and custom packing or labelling can be arranged at quotation.