Penetrant testing is an NTD method used to detect cracks, pores and other discontinuities on the surface of materials. It is especially effective for determining surface defects in metal, ceramic and composite materials.

Welded manufacturing is a special manufacturing method in order to produce products that cannot be manufactured in one piece, that cause extra costs or that are quite difficult in application.

Steel and Aluminum manufacturers are obliged to prove this to the employer even if they make their production with a certain quality. Large-scale employers are proof of this.