IJSRD - International Journal for Scientific Research & Development| Vol. 3, Issue 07, 2015 | ISSN (online): 2321-0613 All rights reserved by www.ijsrd.com 481 An Experimental Analysis on Optimization of Machining Parameters for Surface Roughness using CNC End Milling Process for Al 6351 T6 Pinky Mourya 1 Sharad Shrivastava 2 Dr. Vinod Singh Yadav 3 1,2,3 Rajasthan institute of Engineering and Technology, Jaipur, Rajasthan Abstract— In this paper we have study on CNC end milling, o affect of various machining parameters like, tool feed (mm/min), speed of tool (rpm), diameter of tool (mm) and depth of cut (mm) .this paper is the result of an experiment conducted on AL 6351 – T6 material with three levels and four factors to optimize process parameter and surface roughness. In this paper we have used a L9 (3*4) Taguchi standard orthogonal array for the purpose of designing experiment (DOE).For the purpose of variation calculation we have used Analysis of variance (ANOVA) method. The result of the experiment is quality product generation at the end, which contribute in the higher and quality productivity. In this experiment we were found that order of significant of main parameter decreasing order is Tool feed, Tool speed and Depth of cut. Key words: CNC End Milling Process, Al 6351 T6 I. INTRODUCTION The end milling process is one of the most fundamental processes of the metal removing process. In order to obtain better surface roughness in a CNC milling operation. The final surface roughness might be considered as the sum of two independent effects: 1. the ideal surface roughness is the result of the geometry of tool and feed rate. 2. The natural surface roughness is a result of the irregularities in the cutting operation. Factors such as spindle speed, feed rate, tool diameter and depth of cut that control the chip formations, or the material properties of both tool and work piece are even in the occurrence of chatter or vibrations of the machine tool, defects in the structure of the work material. In the end milling, surface finish and material removal rate are two important aspects. Which require attention both from industry personnel as well as in Research and Development because these two factors greatly influence machining performances? A. Importance of End Milling Process in Present Day Manufacturing In present day manufacturing, the most common cutting tool used with a vertical mill is an end-mill, which looks like a stubby twist drill with a flattened end. An end mill can cut into a work piece either vertically, likes a drill, or horizontally using the side of the end mill to do the cutting. This horizontal cutting operation imposes heavy lateral forces on the tool and the mill, so both must be rigidly constructed. Today, End milling is one of the basic machining processes that allow large amounts of material to be removed quickly. End milling is a very versatile process capable of producing simple two dimensional flat shapes to complex three dimensional interlaced surface configurations. At all types of milling machines, the cutting tool performs a rotational motion that is the cutting motion. The rotation axis of the tool could be horizontal or vertical, depending on machine tool version. The feeding motion is achieved either by part or tool or both, usually on three perpendicular directions. In end milling process cutters diameter is less than the work part‟s width. Fig. 1: Anatomy of End Milling Tool B. Basic Principle of End Milling Process End milling is the most common form of machining, a material removal process, which can create a variety of features on a part by cutting away the unwanted material. The milling process requires a milling machine, work piece, fixture, and cutter. The cutter is a cutting tool with sharp teeth that is also secured in the milling machine and rotates at high speeds. By feeding the work piece into the rotating cutter, material is cut away from this work piece in the form of small chips to create the desired shape. An end mill makes either peripheral or slot cuts, determined by the step- over distance, across the work piece in order to machine a specified feature, such as a profile, slot, pocket, or even a complex surface contour. The depth of the feature may be machined in a single pass or may be reached by machining at a smaller axial depth of cut and making multiple passes. Fig. 2: Principle of end milling process