Proceedings of the 3rd International Conference on Engineering & Emerging Technologies (ICEET), Superior University, Lahore, PK, 7-8 April, 2016.

Transcription

1 Abstract Metal cutting fluids occupy a nucleus position in industry and a play a sheet anchor role in drooping cutting area temperature and provision of requisite lubrication. Numerous factors effect work piece surface quality and tool life while machining, major being the type of cutting fluid vis a vis tool type and working conditions. In this paper,effect of 2 x cutting fluids ( 1 x synthetic & 1 x emulsion being used in local industry )has been examined while turning AISI4140 alloy steel, at specific cutting conditions / parameters i.e spindle speed, feed rate, depth of cut using carbide inserts.during experimentation it was revealed that type of cutting fluid bears significance while studying surface quality of AISI4140 & carbide insert life. Keywords Spindle speed, depth of cut, feed rate, lubricant, tool life and surface finish. 1. INTRODUCTION The usage of cutting fluids in metal working dates back to 1894 when F. Taylor found out an average increment in speed to 33 % whislt cutting fluid is applied and tool life is not compromised [1]. Cutting fluid enhances efficacy of an industrial system while providing lubrication and low temperatures at cutting zones. [2]. Better surface quality and better facet precision are attained by using cutting fluids.. Major properties of metal cutting fluid include:- (i) To present a lubricant layer between metal and tool, to decrease friction. (ii) Act as a coolant to decrease accumulation of heat during machinig. (iii) Blushing away the produced metallic chips. (iv) Acquire requisite worfk piece surface finish. The impulsion these days is to achieve maximized production rate in fewer possible time with better tool life / surface finish. [3]. Lawal et al. [4] carried out turning on AISI 4340 alloy steel using carbide inserts. Water based mineral oil and a synthetic fluid was used as cutting fluid. It was found out that nature of cutting fluid accounted for approx 50 % effect on surface quality. Moreover depth of cut and spindle speed bore approximate 33% & 65% on surface quality respectively. Belluco and De Chiffre [7] carried out experiments to gauge effect of vegetable oils in drilling AISI 316L steel using cobalt based high speed steel tools. Cutting forces, tool wear and chip making ware studied by utilizing said lubricants. Relative increment in tool life coupled with certain decrease in cutting forces was observed during said experiment. In addition it was found out that vegetable oils displayed better than mineral ones. Khan et al. [5]carried out turning on AISI 9310 alloy steel to investigate effect of minimum quality lubrication (MQL) technique utilizing vegetable oil cutting fluid in comparison with dry / flood machining. Surface quality, tool life, interfacial temperature / chip formation were validated using carbide tools at certain given cutting conditions i.e speed (483, 348, 246, 223, m/min), depth of cut (1.0 mm), feed rate (0.10, 0.13, 0.16 and 0.18 mm/rev). An increase in cutting speed / feed rate enhanced

2 tool / chip temperature under minimum quantity lubricant technique. This happened due to changing cutting parameters and energy increment. Surface quality decreased much under flooding in comparison to dry turning due to electro chemical reaction between workpiece and carbide insert. Moreover, principal flank wear appeared to enhance as well underf all conditions. Finally MQL was presumed to be better a option in exhibiting better surface finish. Krishna et al. [6] studied the turning operation on AISI 1040 alloy steel using SAE- 40 / coconut oil with cemented carbide tool. Following cutting conditions were enforced while machinig; Spindle speed (60, 80 and 100 m/min), depth of cut as1.0 mm and feed rate (0.14, 0.16, 0.2 mm/rev. The measurement of temperature done using embedded thermocouple placed at tool insert bottom. The surface quality reduced with corresponding increment in spindle speed / feed rate. Moreover, coconut based oil displayed significantly better performance as compared to SAE-40 oil in terms of average flank tool wear / cutting temperature / tool wear. 2. CONDUCT OF EXPERIMENT The experiments were conducted on TC-20 Johan ford CNC machine.coated carbide tool VNMG V company KYOCERA, made in Japan were employed. Moreover, tool holder, PCLNR2020O-12 N7Y1 was used.work piece used was AISI The composition of work piece is as under:- Elements C Si Mn P S Cr Mo Fig 1: TC-20 Johan ford CNC machine / Tool holder PCLNR2020O-12 N7Y1

3 Details of cutting parameters are as under:- Spindle speed (rpm) Feed rate (mm/rev) Depth of Cut (mm) Turning operations for above mentioned parameters were performed for 4 x cutting mediums namely dry, commercial synthetic cutting oil, commercial soluble cutting fluid (8%concentration), commercial soluble cutting fluid ( 4%concentration). The experiments were performed in a local industry. Similarly,cutting fluids selected are same as employed by said industry with minor variations in concentration of soluble fluids. Aim of experiment is to determine the optimal cutting fluid that bears better surface quality and tool wear while turning AISI Mitutoyo Sj series was used to determine the surface roughness and tool wear of work piece. The procedure adopted to measure surface roughness and tool wear is appended below:- (i) Surface Roughness. 12 x measurements were taken after turning 150mm work conditons given in table 1 using 4 x different cutting mediums.the Mitutoyo Sj series gauge was employed each time for measuring surface roughness. (ii) Tool Wear. The tool wear has been measured in terms of tool life i.e minutes.the workpiece was machined till it reached surface roughness value of 1.6µm using Mitutoyo Sj series gauge else insert met premature failure. Simultaneously, time spent in meeting aforesaid condition was noted,thus bearing tool life. 3. RESULTS Various measurements of surface roughness and tool life achieved during carrying out above mentioned 0.5mm ( depth of cut ) are given in table below:- Spindle speed Feed rate Medium Surface Roughness Tool life (mins) (rpm) (mm/rev) (µm) Dry Dry Dry Synthetic oil

4 Synthetic oil Synthetic oil Soluble(8%) Soluble(8%) Soluble(8%) Soluble(4%) Soluble(4%) Soluble(4%) Fig 2. Surface roughness vs 4 x cutting conditions A line graph has been plotted for various surface roughness values against combination of 3 x cutting conditions at 4 x different cutting media i.e dry, synthetic oil, soluble oils(8%), Soluble oils(4%).following can be implied keeping in view figure1:- (i) The soluble oil (4%) exhibited least surface roughness as compared to other competing media. (ii) While turning AISI 4140 at different cutting conditions, maximum surface roughness values were attained using dry media. (iii) At low spindle speeds coupled with low feed rate, the surface quality tends to enhance. (iv) At higher spindle speeds and feed rates, the surface roughness values enhance profoundly owing to increasing temperature at cutting zone.

5 (v) The findings are in consonance with previously reported literature on various steel alloys. (vi) The soluble oil (4%) is hereby recommended being in expensive and displaying better surface quality of work piece. Fig 3. Tool life vs 4 x cutting conditions A line graph has been plotted for different tool life values obtained against combination of 3 x cutting conditions at 4 x different cutting media i.e dry, synthetic oil, soluble oils(8%), Soluble oils(4%).following can be deduced keeping in view figure 2:- (i) Highest tool life (34.3 mins) was achieved using soluble oil (4%) whereby soluble oil (8%) also showed approximately similar timings ( rpm, 0.10 mm/rev. (ii) Least tool life while turning AISI 4140 at different cutting conditions was obtained at dry cutting conditions ( rpm, 0.20mm/rev). (iii) At low spindle speeds coupled with low feed rate, the tool life tends to enhance. (iv) At higher spindle speeds and feed rates, the tool life reduces. (v) The findings are in consonance with previously reported literature on various steel alloys. (vi) The Soluble oils(4%) and soluble oils(8%) approximately show identical tool lives, however, the former is recommended being inexpensive.

6 4. CONCLUSION Extensive experiments were carried out in turning AISI 4140 alloy steel to obtain desired surface quality and tool life at different sets of cutting parameters using 4 x different media namely dry cutting, synthetic fluid, Soluble oil (4% and 8% concentratins).finally it can be inferred that soluble oils are better to use as cutting fluids as compared to synthetic fluids / dry cutting i.e providing high surface integrity / quality and enhanced tool life. Moreover, it is pertinent to mention that the experiments were performed in local industry and they were using combinations of synthetic fluids and soluble oils (8 %). However, using said soluble oils with reduced 4 % concentration accrued desireable results thus presenting an inexpensive alternative. 5. ACKNOWLEDGEMENT The author is highly indebted to DAUD&SONS, kohat road, Peshawar for the valuable / extensive help extended in carrying out research work at their factory premises. 6. REFERENCES [1] R. F. Ávila, A. M. Abrão, The effect of cutting fluids on the machining of hardened AISI 4340 steel, Journal of Materials Processing Technology 2001;119: [2] D. U. Braga, A. E. Diniz, G. W. A. Miranda, N. L. Coppini, Using a minimum quantity of lubricant (MQL) and a diamond coated tool in the drilling of aluminumsilicon alloys, Journal of Materials Processing Technology 2002;122: [3] J.S. McCoy, Introduction: Tracing the historical development of metalworking fluids, in: J.P. Byers (Ed.) [4] S.A. Lawal, I.A. Choudhury, Y. Nukman, Evaluation of vegetable and mineral oil-in-water emulsion cutting fluids in turning AISI 4340 steel with coated carbide tools, J. Clean. Prod. 66 (2014) [5] M.M.A. Khan, M.A.H. Mithu, N.R. Dhar, Effects of minimum quantity lubrication on turning AISI 9310 alloy steel using vegetable oil-based cutting fluid, J. Mater. Process. Technol.209 (2009) [6] P.V. Krishna, R.R. Srikant, D.N. Rao, Experimental investigation on the performance of nanoboric acid suspensions in SAE-40 and coconut oil during turning of AISI 1040 steel, Int. J.Mach. Tool Manuf. 50 (2010) [7] W. Belluco, L. De Chiffre, Performance evaluation of vegetable based oils in drilling austenitic stainless steel, J. Mater.

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