China produces most of the world's filament — and most of the world's filament horror stories come from skipping due diligence. This 10-step checklist is how professionals buy safely.

  1. Verify the factory: business license, address, line photos/video tour. A "factory" that's a trading company isn't automatically bad — but know which one you're dealing with.
  2. Check certifications: RoHS/CE/REACH certificates with valid numbers; ISO 9001 if you sell B2B.
  3. Demand spec sheets: tolerance, density, tensile, ΔE — in writing.
  4. Order samples first: never skip this. Sample → test → measure → approve.
  5. Agree QC in advance: what gets tested per lot, what happens on failure (replacement? refund? rework?).
  6. Payment terms: T/T with deposit (30–50%) is standard; L/C for containers. Beware 100% upfront with new suppliers.
  7. Incoterms clarity: EXW vs FOB vs CIF vs DDP — know exactly where risk and cost transfer.
  8. Batch codes & traceability: in the contract.
  9. Shipping & customs: get the HS code right, confirm duties, use a forwarder with 3D printing experience.
  10. Build the relationship: suppliers prioritize repeat partners — standing orders get the best slots and prices.

VOXFIL ticks every box above and publishes its QC process openly. Start with samples — 72 hours to your door.