1. Can You See Real Production Capacity?
A reliable supplier should be able to show you extrusion capacity, press tonnage, and in-house finishing lines. When anodizing and powder coating are subcontracted, quality control and lead times sit outside the supplier’s control. Ask for the annual capacity and the number of extrusion presses — it is the fastest way to tell a true manufacturer from a trading company.
2. What Do the Certificates and Test Reports Say?
Look beyond ISO 9001. Request the mill certificate with chemical composition, dimensional tolerance reports, and hardness test data for your alloy (6063-T5, 6061-T6 or similar). A serious supplier will share these without hesitation — and will welcome third-party inspection before shipment.
3. Do They Offer Engineering Support, Not Just Quotations?
The best suppliers review your drawing before quoting: checking wall thickness, tolerances and die design, then suggesting cost-saving modifications. Ask how their engineers handle drawing review and sample approval — the quality of this feedback reveals how the whole order will be handled.
4. Is the Quote Truly All-In?
Compare quotes line by line: extrusion cost, surface treatment, packaging, and freight. Hidden charges appear later as “extras”. Also confirm the MOQ and realistic lead time (15–25 days is typical for standard profiles). A transparent quote now prevents disputes at delivery.