Roll Texturing Surface Treatment for Modem Surface Structures of Automotive

摘要

Automobile manufacturers demand certain surface roughnesses on the sheet to have smooth deep-drawing and lacquering operation. Deep-drawing requires coarse structure forming oil pockets to prevent metal sheet from 'cold welding' to die shoe tool. Lacquering requires fine structures to achieve high quality surface finishes; on the other hand lacquering requires defined roughnesses to have excellent cling to the sheet. A generator switches on the erosion impulse. Conducting particles in the dielectric oil form a dipolar bridge producing intermittent charge of current to be passed onto the roll. A bowl shaped particle is brought to its melting point and a gaseous by product bubble is formed at discharge duct area. After completion the discharge duct collapses and the melted particle is expelled leaving a trough-shaped surface. Comparing blasting and EDT methods with regard to distance of peaks, EDT is significantly higher. Texturing process results can be programmed and reproduced with great regularity and narrow tolerances. Texturing tolerance of the pre-selected roughness is +- 4 percent. Surface qualities with average coefficient of roughness Ra between 0.5 and 15.0 micrometers and 240 to 25 peaks per cm (Pc) can be achieved.