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.

1. Journal for Research| Volume 01| Issue 11 | January 2016
ISSN: 2395-7549
All rights reserved by www.journalforresearch.org 1
Determining the Influence of Cutting Fluid on
Surface Roughness during Machining of EN24
and EN8 steel by using CNC Milling Machine
N. Gopikrishna M. Shiva Chander
Assistant Professor Assistant Professor
Department of Mechanical Engineering Department of Mechanical Engineering
SR Engineering College 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 non-
emulsifiable 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

2. 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)
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(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

3. 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)
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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
Table - 1
Experimental values of surface roughness
SQUARE – EN 24 steel FEED (mm/min) SPEED (rpm) DEPTH OF CUT (mm) SURFACE ROUGHNESS Ra
PIECE 1 1000 1500 0.3 2.7
PIECE 2 1800 2200 0.3 1.8
PIECE 3 2400 800 0.3 3.1
PIECE 4 1600 1400 0.3 2.3
PIECE 5 2800 2000 0.3 1.2
PIECE 6 3300 2500 0.3 1.1
SQUARE – EN 8 steel FEED (mm/min) SPEED (rpm) DEPTH OF CUT (mm) SURFACE ROUGHNESS Ra
PIECE 1 1000 1500 0.3 3.2
PIECE 2 1800 2200 0.3 2.9

4. 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)
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PIECE 3 2400 800 0.3 3.9
PIECE 4 1600 1400 0.3 2.6
PIECE 5 2800 2000 0.3 1.7
PIECE 6 3300 2500 0.3 1.4
Rpm=revolution per minute, = 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.
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