Theoretical Analysis of Thermal Stresses in Electro-discharge Diamond Grinding

Abstract

Excessive heat generated at the machining zone, during Electro-discharge diamond grinding (EDDG), is the major cause of thermal stresses, untempered martensite, overtempered martensite, and cracks. Therefore, the key to achieve good surface integrity in a machined part is to prevent excessive temperature and thermal stresses generated during machining process. A finite element model has been developed to estimate thermal stresses during EDDG when the current is switched-off. First, the developed code calculates the temperature in the workpiece and then the thermal stress field is estimated using this temperature field. Computations were carried out in plane strain condition for different down feeds of the grinding wheel. The effects of time of grinding and feed on thermal stress distribution have been reported. The thermal stresses are found to be higher near top surface at initial time of grinding but shifted away towards bottom after some grinding time.

Keywords:

• Electro-discharge diamond grinding (EDDG)
• Electric discharge machining (EDM)
• Cut-off grinding
• Diamond wheel
• FEM
• Thermal stresses

Acknowledgment

Financial assistance for this work was granted by Council of Scientific and Industrial Research (CSIR), Government of India, through the project no. CSIR/ME/1999/0186 entitled “Abrasive Electro-discharge Grinding of Advanced Engineering Materials.” Authors acknowledge the suggestions of Prof. G. K. Lal of I.I.T. Kanpur during this work.