Improving minimum quantity lubrication in CBN grinding using compressed air wheel cleaning

Abstract The application of minimum quantity lubrication (MQL) in grinding has emerged as an alternative for reducing the abundant flow of cutting fluids, thus achieving cleaner production. Although considered an innovative technique in grinding operations, its widespread application is hindered due primarily to the high heat generation and wheel pore clogging caused by machined chips, harming the final product quality and increasing tool wear on the machine. This study sought to improve MQL use in grinding. In addition to the conventional MQL injected at the wheel/workpiece interface, a compressed air jet was used to clean the mixture of MQL oil and machined chips from clogged wheel pores. Experiments were conducted using external cylindrical plunge grinding on AISI 4340 quenched and tempered steel, and a vitrified cubic boron nitrite (CBN) wheel. The cooling-lubrication methods employed were the conventional flood coolant application, MQL (without cleaning), and MQL with a cleaning jet directed at the wheel surface at different angles of incidence. The main goal of these experiments was to verify the viability of replacing the traditional abundant flow of cutting fluid with MQL and wheel cleaning. The analyses were conducted by measuring the following output variables of the process: workpiece surface roughness and roundness errors, diametrical wheel wear, acoustic emission generated by the process, and metallographic images of the ground surface and subsurface. Results show the positive effects of implementing the cleaning jet technique as a technological improvement of minimum quantity lubrication in grinding in order to reduce the usage of cutting fluids. The MQL technique with cleaning compressed air jet, for a specific angle of incidence (30°), proved to be extremely efficient in the improvement of the surface quality and accurate workpiece shape; it also reduced wheel wear when compared to the other cooling-lubrication methods that were tested (without a cleaning jet).

[1]  M. Tricard,et al.  Innovations in Abrasive Products for Precision Grinding , 2004 .

[2]  Robert Bauer,et al.  An investigation of the effects of wheel-cleaning parameters in creep-feed grinding , 2010 .

[3]  Barney E. Klamecki,et al.  The tribochemical and micellar aspects of cutting fluids , 2005 .

[4]  S. W. Lee,et al.  The effect of high pressure air jet on form accuracy in slot grinding , 2002 .

[5]  Taghi Tawakoli,et al.  Temperature and energy partition in minimum quantity lubrication-MQL grinding process , 2012 .

[6]  M. Stanford,et al.  Investigation into the use of gaseous and liquid nitrogen as a cutting fluid when turning BS 970-80A15 (En32b) plain carbon steel using WC–Co uncoated tooling , 2009 .

[7]  A. Paoletti,et al.  A comparison between conventional abrasives and superabrasives in grinding of SiC-aluminium composites , 2000 .

[8]  Eduardo Carlos Bianchi,et al.  Analysis of surface integrity for minimum quantity lubricant—MQL in grinding , 2007 .

[9]  Ichiro Inasaki,et al.  Tribology of Abrasive Machining Processes , 2004 .

[10]  Mirko Soković,et al.  Ecological aspects of the cutting fluids and its influence on quantifiable parameters of the cutting processes , 2001 .

[11]  W. B. Rowe,et al.  Optimisation of fluid application in grinding , 2008 .

[12]  Peter Krajnik,et al.  Transitioning to sustainable production – Part I: application on machining technologies , 2010 .

[13]  P. Padilla,et al.  Experimental simulation of the efficiency of high speed grinding wheel cleaning , 2006 .

[14]  Helmi Attia,et al.  Power and wheel wear for grinding nickel alloy with plated CBN wheels , 2007 .

[15]  K. Palaniradja,et al.  Heat generation and heat transfer in cylindrical grinding process -a numerical study , 2007 .

[16]  Taghi Tawakoli,et al.  Minimum quantity lubrication in grinding: effects of abrasive and coolant–lubricant types , 2011 .

[17]  Taghi Tawakoli,et al.  Minimal quantity lubrication-MQL in grinding of Ti–6Al–4V titanium alloy , 2009 .

[18]  Niranjan A. Subrahmanya,et al.  Generalized practical models of cylindrical plunge grinding processes , 2008 .

[19]  Aldo Attanasio,et al.  Minimal quantity lubrication in turning: Effect on tool wear , 2006 .

[20]  M. C. Shaw,et al.  Energy Conversion in Cutting and Grinding , 1996 .

[21]  Christopher Donaghy.  Innovation to Benefit Our World, Our Environment and Our Future , 2010 .

[22]  A. Moufki,et al.  A review of developments towards dry and high speed machining of Inconel 718 alloy , 2004 .

[23]  E. Brinksmeier,et al.  Current Approaches in Design and Supply of Metalworking Fluids , 2009 .

[24]  Toshiyuki Obikawa,et al.  High-speed grooving with applying MQL , 2006 .

[25]  S. Malkin,et al.  Thermal Analysis of Grinding , 2007 .

[26]  M. Rabiey,et al.  Dry grinding by special conditioning , 2007 .

[27]  Peter Willett,et al.  Neural network detection of grinding burn from acoustic emission , 2001 .

[28]  W. Rowe,et al.  Handbook of Machining with Grinding Wheels , 2006 .

[29]  T. Brockhoff,et al.  Utilization of Grinding Heat as a New Heat Treatment Process , 1996 .