DETERMINING THE INFLUENCE OF CUTTING FLUID ON SURFACE ROUGHNESS DURING MACHINING OF EN24 AND EN8 STE

Journal for Research| Volume 01| Issue 11 | January 2016 ISSN: 2395-7549

Determining the Influence of Cutting Fluid on Surface Roughness during Machining of EN24 and EN8 steel by using CNC Milling Machine N. Gopikrishna Assistant Professor Department of Mechanical Engineering SR Engineering College

M. Shiva Chander Assistant Professor Department of Mechanical Engineering SR Engineering College

M. Srikiran Assistant Professor Department of Mechanical Engineering Jayamukhi Institute of Technology & Sciences

Abstract Evaluation of the performance of cutting fluid in machining different work materials in order to improve the efficiency of any machining process. The efficiency can be evaluated based on certain process parameters such as flank wear, surface roughness on the work piece, cutting force developed, temperature developed at the tool-chip interface, etc. The main aim of the project is to determine the influence of cutting fluids in metal working. Servo 68 is mainly used for investigation based on surface roughness during milling of EN24 and EN8 steel with carbide tool. Three square pieces of EN 24 material and three round pieces of EN8 material are taken for machining. Different cutting parameters are considered for feed rate, speed and depth of cut. the six pieces are machined with different parameters and surface roughness values are investigated experimentally.

Keywords: Cutting Fluid, Machining Parameters, Tool, Work Specimen, Surface Roughness _______________________________________________________________________________________________________

I. INTRODUCTION Metal cutting is one of the most significant manufacturing processes in the area of material removal. Black defined metal cutting as the removal of metal chips from a workpiece in order to obtain a finished product with desired attributes of size, shape, and surface roughness. Milling is the process of cutting away material by feeding a work piece past a rotating multiple tooth cutter.

The cutting action of the many teeth around the milling cutter provides a fast method of machining. The machined surface may be flat, angular, or curved. The surface may also be milled to any combination of shapes. The machine for holding the work piece, rotating the cutter, and feeding it is known as the Milling machine.

II. INTRODUCTION TO CUTTING FLUIDS Cutting fluids are used in metal machining for a variety of reasons such as improving tool life, reducing workpiece thermal deformation, improving surface finish and flushing away chips from the cutting zone. Practically all cutting fluids presently in use fall into one of four categories: Straight oils, Soluble oils, Semisynthetic fluids, Synthetic fluids. Straight oils are nonemulsifiable and are used in machining operations in an undiluted form. They are composed of a base mineral or petroleum oil and often contains polar lubricants such as fats, vegetable oils and esters as well as extreme pressure additives such as Chlorine, Sulphur and Phosphorus. Synthetic Fluids contain no petroleum or mineral oil base and instead are formulated from alkaline inorganic and organic compounds along with additives for corrosion inhibition. They are generally used in a diluted form (usual concent ration = 3 to 10%).Synthetic fluids often provide the best cooling performance among all cutting fluids. Cutting fluid application strategies are: Flood application of fluid, jet application of fluid, and mist application of fluid.

III. INTRODUCTION TO SURFACE ROUGHNESS Surface Roughness Surface roughness, often shortened to roughness, is a measure of the texture of a surface. It is quantified by the vertical deviations of a real surface from its ideal form. If these deviations are large, the surface is rough; if they are small the surface is smooth. Roughness is typically considered to be the high frequency, short wavelength component of a measured surface

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Determining the Influence of Cutting Fluid on Surface Roughness during Machining of EN24 and EN8 steel by using CNC Milling Machine (J4R/ Volume 01 / Issue 11 / 01)

(see surface metrology). However, in practice it is often necessary to know both the amplitude and frequency to ensure that a surface is fit for purpose.[3]

Fig. 1: Surface Characteristics

Parameters A roughness value can either be calculated on a profile (line) or on a surface (area). The profile roughness parameter (Ra, Rq,...) are more common. The area roughness parameters (Sa, Sq,...) give more significant values.

IV. EXPERIMENTAL SETUP AND PROCEDURE This experiment employed a CNC vertical milling machine. Carbide cutting tool is used. The experiment has been done under different conditions of feed rate, speed and depth of cut as specified above, Cutting fluid – Servo 68 oil. 6 square pieces of EN 24 steel, and 6 EN-8 steel material are taken for machining.

Fig. 2: Working Principle of CNC Milling

Practical Effects In terms of engineering surfaces, roughness is considered to be detrimental to part performance. As a consequence, most manufacturing prints establish an upper limit on roughness, but not a lower limit. An exception is in cylinder bores where oil is retained in the surface profile and a minimum roughness is required.

Roughness is often closely related to the friction and wear properties of a surface. A surface with a large value, or a positive , will usually have high friction and wear quickly. The peaks in the roughness profile are not always the points of contact. The form and waviness (i.e. both amplitude and frequency) must also be considered. The quality of machined surface is characterized by the accuracy of its manufacture with respect to the dimensions specified by the designer. Every machining operation leaves characteristic evidence on the machined surface. This evidence in the form of finely spaced micro irregularities left by the cutting tool. Each type of cutting tool leaves its own individual pattern which therefore can be identified. [4] This pattern is known as surface finish or surface roughness.

Fig. 3: The pattern of the work piece whose surface soughness is to be measured

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Determining the Influence of Cutting Fluid on Surface Roughness during Machining of EN24 and EN8 steel by using CNC Milling Machine (J4R/ Volume 01 / Issue 11 / 01)

Experiments have been performed in order to investigate the effects of one or more factors of the process parameters (spindle speed, feed rate and depth of cut) on the surface finish of the machined surface.The cutting parameters considered are: feed rate 1500mm/min, 2200mm/min, 800mm/min, 1400mm/min, 2000mm/min, and 2500mm/min. Speed - 1000 rpm, 1800rpm, 2400rpm, 1600rpm, 2800rpm, and 3300rpm,and Depth of cut is 0.3mm.

Fig. 4: Surface roughness measuring

This instrument is called as contact type surface measuring instrument (Talysurf). It works on Battery current. It shows the both lower limit and upper limit value of the measured surface.

Cutting Fluid:

Fig. 5: Servo-68 Coolant Oil

Features: Super amazing protection Lessens oil degradation Quick lubrication Applications: Servo system oils are premium quality anti- wear type lubricants formulated with superior quality of hydro treated base stock.

They provide long service life and are recommended for hydraulic and circulation systems of wide variety of equipments. These oils are also used for compressor crankcase lubrication, but are not recommended for lubrication of turbines and equipments having silver-coated components.   

V. RESULTS

SQUARE – EN 24 steel PIECE 1 PIECE 2 PIECE 3 PIECE 4 PIECE 5 PIECE 6 SQUARE – EN 8 steel PIECE 1 PIECE 2

Table - 1 Experimental values of surface roughness FEED (mm/min) SPEED (rpm) DEPTH OF CUT (mm) 1000 1500 0.3 1800 2200 0.3 2400 800 0.3 1600 1400 0.3 2800 2000 0.3 3300 2500 0.3 FEED (mm/min) SPEED (rpm) DEPTH OF CUT (mm) 1000 1500 0.3 1800 2200 0.3

SURFACE ROUGHNESS Ra 2.7 1.8 3.1 2.3 1.2 1.1 SURFACE ROUGHNESS Ra 3.2 2.9

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Determining the Influence of Cutting Fluid on Surface Roughness during Machining of EN24 and EN8 steel by using CNC Milling Machine (J4R/ Volume 01 / Issue 11 / 01)

PIECE 3 PIECE 4 PIECE 5 PIECE 6

2400 1600 2800 3300

800 1400 2000 2500

Rpm=revolution per minute,

0.3 0.3 0.3 0.3

3.9 2.6 1.7 1.4

= micrometers

VI. CONCLUSION The machining parameters investigated influenced the surface finish of the machined work piece significantly.

Experiments have been performed in order to investigate the effects of one or more factors of the process parameters (spindle speed, feed rate and depth of cut) on the surface finish of the machined surface.

1) The surface roughness is more for feed of 2400mm/min, speed of 800rpm and with depth of cut of 0.3mm.

2) By observing the experimental results, the surface finish is good when feed rate of 3300mm/min and speed of 2500rpm is taken for machining EN24 material.[2] 3) By the observation for the parameters of speed 2500rpm and feed of 3300mm/min with same depth of cut i.e.0.3mm, the surface roughness obtained for EN 24 steel is less than the EN 8 steel.

4) It is to clearly observed that by increasing the cutting speed the surface finish imroved is high at the condition of 2500rpm than at 800rpm.

5) The least surface roughness was achieved at spindle speed of 2500 rpm using servo-68 oil was the most effective in reducing surface roughness as spindle speed increased.[1] 6) Finally by the experimentation work on CNC milling with carbide cutting tool by using SERVO-68 coolant oil the surface finish obtained is good for EN-24 steel.

ACKNOWLEDGMENT We thankful to the Raghavendra Spectro Metallurgical Laboratory to do all these experiments successfully, and they well cooperated. We are thankful to SR Engineering college for supporting to do this publication.

REFERENCES 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;119:21-26.

[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 aluminum-silicon alloys,” Journal of Materials Processing Technology 2002;122:127-138 [3] M. Soković, K. Mijanović, “Ecological aspects of cutting fluids and its influence on quantifiable parameters of the cutting processes,” Journal of Materials Processing Technology 2001;109:181-189.

[4] J. John, M. Bhattacharya, P. C. Raynor, Emulsions containing vegetable oils for cutting fluid application,” Colloids and Surfaces A: Physicochem. Eng. Aspects 2004;237:141-150.

[5] W. Belluco, L. De Chiffre, “Testing of vegetable-based cutting fluids by hole making operations,” Lubrication Engineering 2001;57:12-16.

[6] W. Belluco, L. De Chiffre, “Surface integrity and part accuracy in reaming and tapping stainless steel with new vegetable based cutting oils,” Tribology International 2002;35:865-870.

[7] L. De Chiffre, W. Belluco, “Investigations of cutting fluid performance using different machining operations,” Lubrication Engineering 2002;58:22-29.

[8] W. Belluco, L. De Chiffre, “Performance evaluation of vegetable-based oils in drilling austenitic stainless steel,” Journal of Materials Processing Technology 2004;148:171-176.

[9] M. A. Xavior, M. Adithan, “Determining the influence of cutting fluids on tool wear and surface roughness during turning of AISI 304 austenitic stainless steel,” Journal of Materials Processing Technology 2009;209:900-909.

[10] E. Kuram, “Investigation of vegetable-based cutting fluids performance in drilling,” M.Sc. Thesis, Gebze Institute of Technology, Gebze-Kocaeli, Turkey, (in Turkish), 2009.

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