The PPD coating system for the surface treatment of large industrial tools is based on the proprietary Pulsed Plasma Diffusion (PPD) method, which is an alternative to hard chrome plating. It provides effective and economical-friendly protection of tools against wear and tear. The round shape of the processing chamber is emphasised by the casing fashioned from anodised aluminium or powder-coated normal steel. The lower edge is formed by the ribbed fan casing made of powder-coated aluminium.