EFFECT OF MICROWAVE TREATMENT ON WC INSERTS FOR DRILLING OF GFRP COMPOSITES

Due to excellent properties such as high specific strength, high specific modulus, and corrosion resistance, Glass Fiber Reinforced Plastics (GFRP) find wide applications particularly in the aerospace and automotive industries. In order to fabricate structural components of GFRP to near-nett shape, machining of GFRP composites is necessary. Drilling is the most common machining operation for GFRP composites. The fiber pull-out, cracking of matrix during the entry and exit of drill, rapid tool wear, and hole shrinkage are problems associated with machining of GFRP. The present study attempts an innovative idea of improving the cutting performance of Tungsten carbide (WC) inserts (K-20) by post-sintering using microwave irradiation.     

Analysis of cutting properties with reference to amount of coolant used in an environment-conscious turning process

In the recent years, environmentally conscious design and manufacturing technologies have attracted considerable attention. The coolants, lubricants, solvents, metallic chips and discarded tools from manufacturing operations will harm our environment and the earth’s ecosystem. In the present work, the Tukey method of multiple comparisons is used to select the minimum level of coolant required in a turning process. The amount of coolant is varied in 270 designed experiments and the parameters cutting temperature, surface roughness, and specific cutting energy are carefully evaluated. The effects of coolant mix ratio as well as the amount of coolant on the turning process are studied in the present work. The cutting temperature and surface roughness for different quantity of coolant are investigated by analysis of variance (ANOVA)-test and a multiple comparison method. ANOVA-test results signify that the average tool temperature and surface roughness depend on the amount of coolant. Based on Tukey’s Honestly Significant Difference (HSD) method, one of the multiple comparison methods, the minimum level of coolant is 1.0 L/min with 2% mix ratio in the aspect of controlling tool temperature. F-test concludes that the amount of coolant used does not have any significant effect on specific cutting energy. Finally, Tukey method ascertains that 0.5 L/min with 6% mix ratio is the minimum level of coolant required in turning process without any serious degradation of the surface finish. Considering all aspects of cutting, the minimum coolant required is 1.0 L/min with 6% mix ratio. It is merely half the coolant currently used i.e. 2.0 L/min with 10% mix ratio. Minimal use of coolant not only economically desirable for reducing manufacturing cost but also it imparts fewer hazards to human health. Also, sparing use of coolant will eventually transform the turning process into a more environment-conscious manufacturing process.