In this guide
India has a large base of precision machine shops supplying automotive, pumps and valves, electrical and general engineering customers. For international buyers this means competitive pricing on CNC turned and milled components. But machined parts are made to your design, so the quality of the quote and of the parts depends on the information you send.
1. Send complete drawings
Send a dimensioned 2D drawing (PDF) and, where possible, a 3D model (STEP or IGES). The 2D drawing is the controlling document: it carries tolerances, surface finish, threads, notes and revision. A 3D model alone is not enough for an accurate quote.
- Include the drawing revision and the part number.
- Mark critical dimensions clearly, as they drive the inspection plan and the price.
- State the general tolerance standard, for example ISO 2768-m for untoleranced dimensions.
2. Specify the material precisely
Name the grade and standard, not just "steel" or "aluminium". Common examples are free-cutting steel, EN8 / C45 carbon steel, EN19 / 42CrMo4 alloy steel, stainless 303, 304 and 316, aluminium 6061 or 6082, and leaded or lead-free brass. If you need a material certificate, say so up front, because it affects which raw-material suppliers the factory can use.
3. Be realistic with tolerances
Tight tolerances cost money: they mean slower machining, more inspection and higher scrap. Apply them only where function needs them. A part with three critical diameters at ±0.01 mm and everything else at ISO 2768-m will quote very differently from one toleranced at ±0.01 mm all over.
4. Surface finish and treatment
State the roughness requirement (for example Ra 1.6 µm on sealing faces) and any post-processing: heat treatment and hardness, zinc plating, anodising for aluminium, passivation for stainless, or blackening. Each adds a process step and a sub-supplier, so it must be in the RFQ.
5. Quantities and batches
Give the first-order quantity and the expected annual volume. Machining cost depends heavily on set-up time, so a quote for 500 pieces and one for 5,000 pieces per year can differ substantially per piece. Annual volume also tells the factory whether dedicated fixtures make sense.
6. Agree how parts will be inspected
Ask for a first article inspection (FAI) or sample inspection report on the first parts, showing measured values against each drawing dimension. For production lots, agree a sampling plan and which dimensions are checked. Where needed, request CMM reports for complex geometry and material certificates for each heat.
7. Approve samples before production
Always approve samples before releasing the bulk order. Keep an approved sample (a "golden sample") on both sides, so later lots can be compared against it.
CNC part RFQ checklist
| Information | Why it matters |
|---|---|
| 2D drawing + 3D model, with revision | Defines the part exactly |
| Material grade & certificate need | Price and traceability |
| Critical tolerances, general tolerance class | Machining method and inspection cost |
| Surface finish, heat or surface treatment | Extra processes and lead time |
| Order and annual quantity | Set-up cost per piece |
| Inspection & documents | Quality assurance |
| Packing & delivery terms | Protects finished surfaces in transit |
Have drawings ready? Send us your requirement. Please tell us you have drawings and we'll arrange a suitable way to receive them confidentially.
Frequently asked questions
What files do Indian machine shops need for a CNC quote?
A dimensioned 2D drawing (PDF) with tolerances and notes, plus a 3D model (STEP or IGES) if available, the material grade, surface finish and treatments, and the order and annual quantities.
How can I check the quality of CNC parts from India?
Approve samples first with a first article inspection report against every drawing dimension, then agree a sampling plan, inspection reports and material certificates for production lots.
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