Times are tough. QC is often categorized as "overhead,” i.e., it doesn't contribute directly to the bottom line of the balance sheet. As a result of the accounting methods used, the QC department and its staff are considered as expendable when it comes to cost cutting measures.

A better means of assessing the "value" of QC is to consider the costs incurred when the customer rejects the materials or product;  the intangible cost of the lost of customer confidence, the direct cost of replacing the rejected materials, and the direct costs of transportation, i.e., delivering the rejected material, picking up and returning the rejected material and delivering the replacement  materials. Where this case, the "value added" by the efforts of the QC department would be a better reflection of the "cost" of not providing proper QC.

In your case the supplier should look at the factors I listed above and incorporate the costs of ordering the tube, transporting the tube, handling the tube, cutting the tube, shipping it to your facility, picking the rejected tubes up to return it to the supplier, unloading it and storing it until it can be returned to the manufacturer or scrapped. This is no small matter because the costs add up very quickly and in many cases can exceed the cost of the original sale and any expected margin (profit).

I have an opportunity to play a part in writing the project specifications on some jobs that I am involved with. When I am involved, the costs incurred by my clients to handle rejected material are charged against the supplier, i.e., handling, reinspection, etc. The original incoming/receiving inspection is borne by the client as it should be part of the client's QC program, but once the  material is rejected, the clock starts ticking and all the charges of handling the material a second time, loading the old, unloading the new, reinspection, etc. is borne by the supplier. This penalizes the "bad" supplier for not providing the proper materials the first time. Suppliers learn very quickly that is unwise to provide substandard materials when it results in charges against their invoiced amount.

Nothing speaks louder than money when dealing with contractors, suppliers, and manufacturers.

Best regards - Al