Author:

Keywords:

ELID-grinding, cermets, Design of Experiments, maximal material removal rate

Abstract:

ELID-grinding of cermets has been carried out on a retrofitted Jung surface grinder with different cast iron-bonded (CIB) diamond wheels. In case of rough grinding, with a wheel of 46 µm abrasives, ELID-grinding is preferable compared to grinding with a conventional resin-bonded wheel or a CIB wheel without ELID. Resin-bonded wheels are characterized by low G-ratios and are prone to chattering effects. Metal-bonded wheels are very durable, and especially for avoiding glazing effects during longer grinding cycles, ELID-grinding is the best choice. The maximal MRR in ‘ELID-roughing’ on the used surface grinder is measured to be 1 mm³/s, leading to a roughness of about 0.4 µm Ra. The ‘ELID-finishing’ steps are implemented on the same grinding machine, so the workpiece does not need to be dismounted. Several sets of experiments based on the Design of Experiments method show that lower axial feeds and higher duty ratios of the power supply improve the surface quality effectively. With the wheel of 10 µm grit size, chattering can be avoided by limiting the theoretical MRR to 0.05 mm³/s. To obtain a final Sa roughness below 10 nm, the last finishing wheel should remove less than 0.3 10-3 mm³/s. The total processing time of the finishing steps is less than 30 minutes for a workpiece area of 375 mm³.