No matter how you try to improve the performance of a quality system, improve employees workmanship, improve the engineering process etc. If you are not involved in the actual activity of manufacturing the part in question then you must be considered nen-productive. And as a result add no value to the part. You have not changed anything about the part for bar/ billet state to its required form.
The time its spent in your posession, its losing value as its paying your wage . If you are changing it to comply to customer requirement then you are adding value. Ie: - If you supply the part to the customer without it being manufactured (in bar. billet format) then its worthless to the customer. If supply the part manufactured as required then the customer will pay up for the part. If supply the part manufactured as required then conduct quality activities on the part, the customer will only pay for the manufactured part, not the quality activity, thus the quality activity is not adding value!