Comparison of tool life and surface roughness with MQL, flood cooling, and dry cutting conditions with P20 and D2 steels S W M A I Senevirathne M.Eng., B.Sc. H K G Punchihewa Ph.D., M.Sc. B.Sc. Department of Mechanical Engineering University of Moratuwa, Sri Lanka

Minimum Quantity Lubrication Aerosol MQL (50 – 400 ml / hr) Vs Flood (~10 l / min) Evaporative cooling dominates Better lubrication Not obstructing Promising results Department of Mechanical Engineering

Department of Mechanical Engineering Rationale High cost of CF : 20% of total mfg. cost Trend of MQL Effect of MQL on hard-to-cut material? Effect of work-piece material on machining performance? Department of Mechanical Engineering

Department of Mechanical Engineering Aim & Objectives Aim Study the effect of MQL & WP material on machining performances Objectives To select material for the experiment To evaluate machining performance against MQL & WP material Department of Mechanical Engineering

Department of Mechanical Engineering Cooling Condition Material Response variable TNW | SR P20 Dry Flood MQL D2 Experiment Design Department of Mechanical Engineering

Department of Mechanical Engineering Research parameters Predictors Work material P20 D2 Cooling method Dry Flood MQL Response variables Tool nose wear Surface roughness (Ra) Department of Mechanical Engineering

Controlled Parameters Value   Turning Operation Straight Flow Rate (MQL) 160 ml/ hour Feed Rate 0.5 mm / rev Pneumatic Pressure 7 bar Depth of Cut 0.5 mm Flow Rate (Flood) 9 l/min Length of the Cut 500 mm Nozzle Target Area Rake Face Surface Cutting Speed 150 m/min Nozzle Angle (H) ≈ 60o Spindle Speed 1220 rpm Nozzle Distance 150 mm Department of Mechanical Engineering

Department of Mechanical Engineering Experimental setup 3.0 kW horizontal lathe WC tool insert 90.3 HRA Emulsion CF 1:9 v/v water Work-pieces AISI P20 (52 HRC) AISI D2 (62 HRC) Department of Mechanical Engineering

Department of Mechanical Engineering Application of MQL Applied to : rake face Flow rate : 160 ml / hr Pressure : 7 bar Department of Mechanical Engineering

Department of Mechanical Engineering Response variables Tool nose wear Arithmetic average SR (Ra) CNC-CMM Resolution : 0.0001 mm Digital SR tester Accuracy : 0.01 µm Cut-off length : 2.5 mm Department of Mechanical Engineering

Tool Nose Wear & Mean Ra Mean Tool Nose Wear (mm) Mean Ra (μm)   Mean Tool Nose Wear (mm) Mean Ra (μm) Cooling Condition P20 D2 Dry 0.0643 0.0557 1.514 1.623 Flood 0.0283 0.0299 1.406 1.373 MQL 0.0867 0.0907 1.594 1.518 Department of Mechanical Engineering

Department of Mechanical Engineering ANOVA of P20 Groups TNW groups F = 33.37 | P = 0.001 (<0.05) | CI = 95% ⸫ at least one mean TNW of the tested 3 groups is significantly different from the others Ra groups F = 308.32 | P = 0.000 (<0.05) | CI = 95% ⸫ at least one mean Ra of the tested 3 groups is significantly different from the others Department of Mechanical Engineering

Department of Mechanical Engineering ANOVA of D2 Groups TNW groups F = 42.12 | P = 0.000 (<0.05) | CI = 95% ⸫ at least one mean TNW of the tested 3 groups is significantly different from the others Ra groups F = 251.87 | P = 0.003 (<0.05) | CI = 95% ⸫ at least one mean Ra of the tested 3 groups is significantly different from the others Department of Mechanical Engineering

Department of Mechanical Engineering t-Test on P20 Groups   Tool nose wear Ra Flood MQL Dry Significantly high Significantly low Department of Mechanical Engineering

Department of Mechanical Engineering t-Test on D2 Groups   Tool nose wear Ra Flood MQL Dry Significantly high Significantly low Department of Mechanical Engineering

Department of Mechanical Engineering Work Material Effect   Tool nose wear Ra Dry (P20) Flood (P20) MQL (P20) Dry (D2) Not Sig. high Flood (D2) low MQL (D2) Department of Mechanical Engineering

Department of Mechanical Engineering Work Material Effect Department of Mechanical Engineering

Department of Mechanical Engineering Conclusions MQL causes higher TNW in P20 & D2 with coated carbide tools SR of P20 & D2 with MQL was higher than flood cooling In P20, SR with MQL higher than dry cutting Non-favourable performance with P20 or D2 steels Department of Mechanical Engineering

Department of Mechanical Engineering Conclusions TNW with P20 & D2, in dry, flood cooling, or MQL, is not different SR varied significantly with the material In dry, SR in D2 lower than P20, Flood cooling & MQL SR in P20 lower than D2 Department of Mechanical Engineering

Department of Mechanical Engineering Thank you! Department of Mechanical Engineering