Surface Roughness Prediction Modeling for AISI 4340 after Ball End Mill Operation using Artificial Intelligence

Now a days a manufacturing system is oriented towards higher production rate, quality, and reduced cost. Surface roughness is an index for determining the quality of machined products and is influenced by the cutting parameters. In die manufacturing industries Surface roughness of dies are considered as a vital quality characteristic. For the complex shapes of a die, three dimensional machining is done by ball end mill in the most cases. In this study the average surface roughness value (Ra) for a die material AISI 4340 has been measured after ball end milling operation. Before conducting the experiments a design of experiment was done with Response Surface Methodology (RSM). 49 experiments have been conducted varying Cutter Axis Inclination Angle (Ø degree), Tool Diameter (d mm), Spindle Speed (S rpm), Feed Rate (fy mm/min), Feed (fx mm), Depth of Cut (t mm) in order to find Ra. This 49 data has been used for training purpose and more 25 data has been collected with random selection of input parameters and used as testing data set. The train ing data set has been used for train different ANFIS and RSM model for Ra prediction. And testing data set has been used for validate the models. Better ANFIS model has been selected for minimum value of mean square error (MSE) which is constructed with two double sided Gaussian membership functions (gauss2MF) for each input variables and a linear membership function for output. The Selected ANFIS model has been compared with theoretical model and RSM. This comparison was done based or Root Mean Square Error (RMSE) and Mean Absolute Percentage of Error (MAPE). The comparison shows that the selected ANFIS model gives better result for training and testing dataset. So, this ANFIS model can be used further for predicting surface roughness of a commercial die material (AISI 4340) for ball end milling operation. Correlation test shows that only cutter axis inclination angle and feed (fx mm) have correlations with surface roughness.