The standard applies to resistance welding machines used to produce spot and roller seam weld joints on aerospace components. The qualification of a resistance welding machine is obtained by confirmation of the acceptance test results by a quality assurance authority. The acceptance test primarily consists of checking the conformity of products welded with the machine when compared with reference samples, and is not a measuring acquisition of characteristic data of the machine itself. This is done by metallographic and strength examination methods. This quite unusual procedure is due to still insufficient knowledge of the interrelationship between specific features of the machine and their impact on the parts to be joined.#,,#