DETERMINATION OF OPTIMUM CUTTING PARAMETERS ON FREE FORM SURFACES IN TERMS OF FORM ERRORS AND MACHINING TIMES

Year 2018, Volume: 36 Issue: 4, 1153 - 1164, 01.12.2018

Harun Yaka Halil Demir Arif Gök Harun Akkuş

Abstract

In this study, the most suitable cutting conditions were determined from which obtained the lowest form error. Freeform surfaces were machined in CNC milling machine. In experiments, Al7075 series material was used because of its special features. Because Al7075 series material is frequently used in many areas with high strength and easy machinability. Firstly, four factor consisting of cutting speed, feed rate, step over, machining strategies were determined. Later, 4 levels were selected for the each factor according to manufacturer catalog of the cutting tool. After an experiment list was created. The Taguchi method was used while the creating of L16 ortogonal array. At the end of the experiments, form errors were found and signal noise (S/N) ratios determined with using the Taguchi method. The most suitable cutting conditions were determined as a result of the analyzes of expeiments. According to Taguchi method, the 2-3-1-1 orthogonal array outside the designed L16 was the optimum condition; So, the smallest form error value was obtained by 140 m/min cutting speed, 800 mm/min feed rate, 0.5 mm step over and parallel machining strategy. Also in this study, it was appeared that the cutting factors that affect form error, which are the step over, cutting speed, feed rate and machining strategies in order of importance. Moreover, in ANOVA results, step over showed significance at the 95% confidence level on form error. It is possible to comment on the best machining conditions according to the obtained machining times and form errors.

Keywords

Machining of Al7075, ANOVA, form error, Taguchi Method, 3D scanning.

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