- Start from the hardest feature, not the supplier list
- Six questions that separate a supplier from a quote machine
- A tolerance claim without feature, material and volume is marketing
- Watch for the five red flags in a first quote
Start from the feature
List the three hardest things about your part — the tightest tolerance, the thinnest wall, the trickiest material — then find the machining supplier who can do those three. The feature is the spec; the supplier is the delivery mechanism.
Six questions, and the answers that matter
1. Which feature, in which material, at what volume? 2. What report format do you ship? 3. What is your rework rate on parts like mine? 4. How do you handle a nonconformance? 5. What does your DFM note look like? 6. Who signs the first-article report? General answers mean you are reading a quote machine, not a shop.
Reading tolerance claims
A tolerance claim without a feature, material and volume is marketing. 'We hold ±0.001 mm' tells you nothing; 'we hold ±0.003 mm on this wall at this volume' tells you everything. Ask for the context and the report behind every number.
Five red flags
A blended number with no breakdown. No question about GD&T or finish. A price in seconds. A refusal to show a sample report. A tolerance claim that ignores your hardest feature. Any two, keep looking.
How do I de-risk a first order?
Small batch, require a first-article report, consider third-party inspection on lot one. A supplier that welcomes that expects to pass it.
What should I send to compare suppliers?
The same 3D and 2D, quantity and finish, to every supplier, so the quotes are comparable, not just the prices.
Apply the six questions and see who answers like a supplier.
Send a 3D file to [email protected] · +86 13126536955
Continue reading: Machining Applications · Machining Cost · Machining Materials
Standards referenced on this page
- ISO 9001 — Quality management systems — Requirements
- ASTM E8/E8M-21 — Standard Test Methods for Tension Testing of Metallic Materials