ELECTRICAL-DISCHARGE WHEN MACHINING MEDIUM-DENSITY FIBERBOARD AND TOOL WEAR

Electrical potentials between the workpiece and cutting tool have been shown to be generated when cutting green and dry wood. The voltages have been reported as relatively constant. A series of turning tests on medium-density fibreboard (MDF) were undertaken to characterize the electrical potentials in wood machining. The results indicated numerous discharges generally from the MDF-workpiece (cathode) to the tool (anode). However, both voltage and current reversals or discharges occurred from the tool to the MDF-workpiece. The reversals occurred simultaneously with electrostatic discharges within the MDF-workpiece. The possibility of an electric discharge machining effect on tool wear is also discussed. These electrical discharge characteristics from wood machining could provide insight for the wear mechanisms for dry wood and wood products as well as for other dielectric materials.