Experimental analysis of machining performance based on selected cutting parameters for smart CNC turning environment

Abstract

The purpose of this study is to analyze turning performance of Aluminium Alloy 6061 based on selected cutting conditions such as cutting speed, feed rate and depth of cut, in terms of acceptable range of surface roughness, with the integration of STEP-NC as a data structure. STEP-NC, an acronym for Standard for the Exchange of Product Model Data for Numerical Control is developed by the ISO committee with the intention of replacing the outdated G-codes used for machine execution. G-codes only contain point to point instructions directing the machine to move and machine the parts with lack of intelligence. Important machining parameters such as tolerance information, feature information and cutting tools information are missing and cannot be utilized at CNC level. In addition, it commonly embedded with specific extension of different vendors’ added code depending on its controller making it lacks of interoperability. STEP-NC on the other hand provides comprehensive data structure and may provide information such as material properties, value of surface roughness, part feature and workingstep for the process. In this study, dry cutting operations of a 100mm Aluminum Alloy 6061 bar were turned into a 50mm length and 24mm final diameter based on the combinations of various cutting parameters set using Design of Experiments (DOE) method. The experimental results were statistically analyzed to study the influence of cutting parameters on surface roughness. Based on this, to suit the smart CNC turning environment, regression model were developed and were used in Graphic User Interface (GUI) algorithm in STEP-NC for the surface roughness value output. The outcome of this study shows that feed rate, cutting speed and depth of cut have significance effects on the surface roughness and the best surface roughness condition is achieved at a low feed rate 0.07 mm/rev, high cutting speed 280 m/min and depth of cut 0.1 mm. The results also show that the feed rate has big effect on surface roughness followed by cutting speed and depth of cut.