Experimental Study On Effect Of Installation Orientation For Process System On Milling Eccentricity

There are several critical factors which have an adverse effects on work piece surface finish,dimensional accuracy and tool life etc.,while eccentricity is one of them.It is defined as deviation from the circular path and in terms of manufacturing technology when spindle,tool holder and milling cutter revolves around the line parallel to their cutting axis.The major reasons for the occurrence of eccentricity are clamping deviation and geometric imperfections and moreover,it consists of two geometric parameters which are offset magnitude vector e_c and angular location vector_c.A small offset value may cause insignificant consequence in macro-end milling,while in micro-end milling,it can outcome in unstable periodic deviations in chip load and milling forces along with poor surface finish etc.This study was taken into consideration from the interest that there should be an approach through which final eccentric error,cutting forces and surface roughness value should be reduced in order to improve the processing quality.For that,combinations were made with spindle,tool holder and milling cutter by fixing them together at different orientations.If orientations affects the eccentricity,cutting forces and surface roughness value highly then such a combination can be selected which will be exhibiting minimum precarious parametric values among all other combinations.It is very beneficial in the world of advancements.The main research works of this thesis is:1)Problem solution was found out through performing numerous experiments on CNC vertical milling center.Measuring the geometric imperfections from different levels of the combination spindle,tool holder and milling cutter with Swiss SYLVAC dial gauge at different orientations.During analysis,offsets at different levels at different orientations for all elements of combination were found out.Then they were combined from first level of spindle to the bottom level of milling cutter for all combinations.During combining it was observed that central axial line of every particular element at every particular orientation was not a line that was basically a curve.Curve fitting method was applied on the whole experimental data twice in order to convert curves into a lines.Based on central lines,their deflected profiles were drawn which exhibits the actual conditions of the machining elements.2)In order to testify the above problem statement,the same measurement procedure and analysis procedure were applied on five other milling cutters of different diameters,different cutting edges and of different materials to assure that really orientations have valuable effects on the eccentricity.Graphs were plotted for the comparison of first level and last level eccentric values between different orientations in order to show the clear deviation.3)24 cutting-tests were carried out by keeping the same cutting conditions all along with three other milling cutters of different diameters.All test-cuts were done on CNC vertical milling center through using the line-milling operation.SDC-C4F type force measuring system was used made by the Beijing University of Aeronautics.During every test-cut,force measuring system was activated for the recording of cutting forces.After every test-cut MarSurf PS1 instrument was used for the measurement of surface roughness value.Detailed analysis on cutting force wavelengths in time-domain was done with the designing and implementation of Chebyshev's filter.Moreover,average cutting forces for every particular wavelength at every particular orientation was calculated through the mean command.Graphs were illustrated through using the average cutting forces and surface roughness values in order to show the clear variation in between different orientations.Research results and conclusions of this paper are as follows:1)The eccentricity of combination#6 was about 0.019 mm,the difference between the eccentric value of combination#2 and combination#6 was about 0.044 mm whereas orientation of milling cutter was same only the orientation of tool holder changes.It showed that orientations affects the eccentricity highly by displaying the large difference in between them.It also pretends that the orientation of every element was very important in order to increase the processing quality.Same conclusions were obtained from all other milling cutters 2-6.2)The average cutting force across combination#1 was about-377.239 N,whereas combination#3 exhibits about 70.649 N.The difference between combination#1 and combination#3 was about-447.888 N.In these 2 combinations the orientation of tool holder was same only the orientation of milling cutter changes.The cutting forces varies periodically,at one orientation one tooth was having maximum force and then at another orientation another tooth was having maximum force.Experimental results based on cutting forces designated that orientations affects the cutting forces highly with large cutting force differences.Same conclusions were gotten from the results of other 2 milling cutters as well.3)Tool#7:Combination#7 exhibits 0.50?m and combination#8 exhibits 2.93?m whereas the difference in between these 2 combination was of 2.43?m.In these combinations,orientations of tool holder was same only the orientations of milling cutter changed gradually.Experimental results based on surface roughness also nominated that orientations affects the surface roughness value highly by showing huge difference in between them.Same conclusions were gotten from the results of other 2 milling cutters as well.