The seven steps
1. Drawing review (design for manufacturability) Once we have the drawing or sample, we check three things: can the geometry be machined reliably, can the tolerances be held, and is there a more economical alternative. This step is free but often the most valuable — a single change here can remove cost from the whole project.
2. Quotation Pricing is based on material, machining time, surface treatment, inspection requirements and quantity. Quantity matters a great deal: the same part can cost several times more at 100 pieces than at 10,000, because sampling and setup costs are spread over more units.
3. Sampling Simple parts typically take 3–5 working days, moderately complex parts 5–7, and parts with special processes or complex geometry 7–15. Samples are supplied with measured dimensions for approval.
4. First article approval After the sample is approved, a first article is produced and checked dimension by dimension — critical sizes, threads, appearance — before the batch is released. This is the step that prevents a whole batch from being scrapped.
5. Production and patrol inspection Checks are made by operation, with the focus on dimensional stability. High-volume orders run continuously with automatic bar feeders to reduce operator-to-operator variation.
6. Inspection after surface treatment Plating, anodising and blackening change both dimensions and appearance, so parts are re-checked afterwards — especially mating dimensions.
7. Pre-shipment inspection and packing Sampling or 100% inspection as agreed, then packing designed for rust prevention, impact protection and part separation.
What to prepare
To get a fast and accurate quote, send as much of the following as possible:
- Drawings — PDF, DWG, DXF, STEP, STP, IGS, XT are all fine
- Material — grade or performance requirement; we will advise if it is not specified
- Quantities — sample, pilot and production volumes separately
- Critical tolerances — highlight mating dimensions, geometric tolerances and surface finish
- Surface treatment — process, colour, coating thickness, salt-spray requirement
- Inspection — whether 100% inspection, FAI reports, material certificates or full dimensional reports are needed
- Packing and labelling — any special requirements
If there is no complete drawing yet, send a sample, a sketch or a reference photo and we can assess feasibility first.
Three common cost traps
- Over-tight tolerances — putting ±0.01 on non-mating dimensions multiplies inspection time
- Ignoring material substitution — some grades have long lead times and high prices; an equivalent grade is often more economical
- Forgetting the surface treatment sequence — coating thickness affects thread fit and bore size, so allowance must be built in
Getting these three settled at drawing stage usually removes a meaningful share of the cost.