Studies on deep hole drilling of AISI 1045 steel using different cooling methods

Abstract

The standard process of making holes in metallic and non metallic materials is Drilling which is the easiest procedure followed in industries With an increased hole depth requirement in modern scenario such demands increase the requirement of more sophisticated machines and tooling The increase in hole depth is usually referred as deep hole drilling which is a complex process performed with special cutting tools on specific machines and characterized by a high metal removal rate and hole accuracy A hole deeper than ten times the diameter L D ratio can be considered a deep hole which requires a specialized drilling technique Deep hole drilling is one of the most complicated metal cutting processes and one of the most difficult to perform on CNC machine tools or machining centres under conditions of limited resources It involves the use of long shank drill bits with cutting inserts at the end with a hole centrally available for supplying a coolant during metal removal process for flushing out the chips produced During deep hole drilling process forces produced on the deep hole drill give rise to a resultant radial force which drives the drill bit in radial direction during the drilling process The radial force direction is of critical significance with respect to stability of cutting tool tool guidance generation of cutting forces material removed and hole size accuracy and apart from this the radial force affects the surface integrity of produced hole tool life and tool performance In the present investigation experimental studies on deep hole drilling was carried out on a CNC machine to identify the relationship between spindle speed feed rate and coolant pressure and air pressure versus surface roughness circularity error cylindricity hole wall temperature tool wear and amount of material removed for application of cutting oil and emulsion as lubricant and through the Minimum Quantity Lubrication MQL approach newline