Aman Aggarwal

Optimization of machining techniques — A retrospective and literature review

In this paper an attempt is made to review the literature on optimizing machining parameters in turning processes. Various conventional techniques employed for machining optimization include geometric programming, geometric plus linear programming, goal programming, sequential unconstrained minimization technique, dynamic programming etc. The latest techniques for optimization include fuzzy logic, scatter search technique, genetic algorithm, Taguchi technique and response surface methodology.

Taguchi-fuzzy multi output optimization (MOO) in high speed CNC turning of AISI P-20 tool steel

Research highlights? The multi output high speed CNC turning of AISI P-20 tool steel is optimized using fuzzified Taguchi approach. ? In multi-response problem, all 4 responses tool life, power consumption, cutting force and surface roughness were simultaneously considered. ? It is concluded cutting speed (160m/min), nose radius (0.8mm), feed (0.1mm/rev) & depth of cut (0.2mm) yield ptimal result. ? Most significantly- cryogenic machining environment is favourable in increasing tool life and reducing surface roughness, cutting force and power consumption compared to wet coolant. This paper presents the application of Taguchi method with logical fuzzy reasoning for multiple output optimization of high speed CNC turning of AISI P-20 tool steel using TiN coated tungsten carbide coatings. The machining parameters (cutting speed, feed rate, depth of cut, nose radius and cutting environment) are optimized with considerations of the multiple performance measures (surface roughness, tool life, cutting force and power consumption). Taguchis concepts of orthogonal arrays, signal to noise (S/N) ratio, ANOVA have been fuzzified to optimize the high speed CNC turning process parameters through a single comprehensive output measure (COM). The result analysis shows that cutting speed of 160m/min, nose radius of 0.8mm, feed of 0.1mm/rev, depth of cut of 0.2mm and the cryogenic environment are the most favorable cutting parameters for high speed CNC turning of AISI P-20 tool steel.

Multicharacteristic optimisation of CNC turned parts using principal component analysis

This paper optimises the multiple characteristics (tool life, cutting force, surface roughness and power consumption) in CNC turning of AISI P-20 tool steel using Principal Component Analysis (PCA). Five controllable factors of the turning process were studied at three levels each viz cutting speed, feed, depth of cut, nose radius and cutting environment. L27 Orthogonal array was used for conducting the experiments. The single response optimisation was conducted by Taguchi method. PCA was employed to correspond to multi response cases. The optimum combination of process factors based on first principal component was determined which was subsequently studied by extracting more then one principal component and integrating into comprehensive index. Finally, the Analysis of Variance (ANOVA) was used to find out the most influential CNC turned parameter for multiple response problems.

Modelling of machining parameters and cooling conditions in hard turning of AISI p-20 tool steel using response surface methodology and desirability graphs

This paper presents mathematical models for correlating the CNC machining parameters such as cutting speed, feed rate, depth of cut, nose radius, with the cutting force acting on the cutting tool during turning of prehardened P-20 tool steel. The face centred central composite design module of Response Surface Methodology (RSM) has been used for conducting the experiments. Machining is done under three different environmental conditions - dry, wet (conventional coolant ILO cut 154 Indian Oil) and cryogenic (liquid nitrogen). The significance of the mathematical models developed was ascertained using desirability graph and confirmation experiments. The results obtained show that the mathematical models are useful not only for predicting optimal process parameters for achieving the desired quality but also for achieving the process optimisation. The cutting force contours have been generated from the model equations. Desirability graphs are also drawn giving minimum cutting force a value of one.

Simultaneous optimisation of conflicting responses for CNC turned parts using desirability function

This paper optimises multiple characteristics (tool life, cutting force, surface roughness and power consumption) in CNC turning of AISI P-20 tool steel using desirability function. Four controllable factors of the turning process viz. cutting speed, feed, depth of cut and nose radius, were studied. Face centred central composite design was used for experimentation. Response surface methodology was used for modelling the responses. Desirability function was used for single response and multiple response optimisation. The functions are plotted giving equal weightage to all the four responses.