Increasing of cutting performance of PVD coated cemented carbide inserts in chipboard milling through improvement of the film adhesion, considering the coating cutting loads

Coated cemented carbide cutting inserts that had been pre-treated to remove from their surface the remaining highly deformed cobalt binder layer were examined by carrying out a series of cutting experiments, in order to evaluate their performance when used in chipboard milling. The chip formation mechanism and the tool loading, required to determine the occurring stress distribution in the applied coatings during chipboard milling, was analytically investigated by means of a developed FEM simulation of the material removal process, verified through cutting force measurements. The coating stresses during milling, due to cutting loads, as appropriate FEM calculations concerning their distribution on the tool rake face show, are below the coating's fatigue strength. The coating and the tool wear development are mainly caused by abrasion mechanisms at low cutting temperatures. The investigations indicated that removal of the Co binder phase by pre-treatment of the tool's substrate through grit blasting or chemical etching, results in better adhesion properties, therefore providing superior wear behaviour to the tool.