Surface Roughness In The CNC Milling Industry

Abstract - CNC milling is most commonly used in industry and machine shops for machining parts to precise sizes and shapes. Out of different types of milling processes, end milling is one of the most common and vital metal cutting operations used for machining parts, because of its capability to remove materials at faster rate as well as a reasonably good surface quality. Inconel 718 is one of the most commonly used nickel based super alloy having a high temperature applications such as aerospace industries and gas turbines in aviation. It is known as the most difficult to cut materials due to its high strength even at high temperatures, low thermal conductivity, and rapid work hardening. Their machining is preferably done on the CNC Milling

Surface finish is one of the prime requirements of customers for machined parts. In most of machining operations the main objective is optimization of surface roughness. The higher value of surface roughness generates on the machining parts and due to rework or scrap results into increase in cost and loss productivity. Surface roughness is major factor in modern CNC milling industry. The purpose of this work is focused on the analysis of optimum cutting conditions to get lowest surface roughness in milling by regression analysis. To investigate the effect of cutting parameter like spindle speed, feed rate and depth of cut on surface

The average surface roughness is the integral absolute value of the height of the roughness profile over the evaluation length (L) and was represented by the equation given below.
Where ‘L’ is the length taken for the formula,

Observation and ‘Y’ is the ordinate of the profile curve.
Surface roughness tester (Stylus probe type profilometer) is uses to measure surface roughness of work piece in microns (µm).
Material removal rate (MRR): Material removal rate is the volume of material removed per unit time from the work piece surface. We can calculate material removal rate as the volume of material removed divided by the time taken to cut. The volume removed is the initial volume of the work piece minus the final volume. The cutting time is the time needed for the tool to move through the length of the work piece this parameter strongly influences the finishing grade of the work piece.

Where, Q = MRR (mm3/min), ae = Radial Depth (mm), ap = Axial Depth ( mm), vf = feed rate (mm/min).
Machining Time (min):
Power Consumption(kw)
Tool Life