Verify real manufacturing capability
Confirm the supplier actually makes cores in-house: foil corrugation, bonding or brazing, and leak testing (pressure or helium). A trading company that only resells will struggle with custom sizing and quality control. Ask for a factory video audit or a third-party inspection.
Engineering and quality systems
Look for sizing software, a performance test rig, material certificates for aluminum or polymer grades, and ISO 9001. A capable partner returns drawings and performance curves, not just a price.
Commercial red flags
Be cautious if a supplier quotes with no drawing, refuses to disclose test methods, has no reference projects, or is vague about Incoterms and payment terms. These signals often precede quality or delivery problems.