Selection of non-conventional machining process using CRITIC-CODAS method

Abstract

High strength materials such as stainless steel, titanium, ceramics, and composites are widely used in the manufacturing of various components for aircraft, missile, turbine, automotive, tool and die-making, etc. These high-strength and difficult-to-machine materials are processed using a variety of non-conventional machining (NCM) processes to produce the desired forms with required dimensional accuracy and surface finish. The NCM processes are costly and consume a lot of electricity, thus, choosing the best NCM process is critical for cost-effective machining. The proper selection of the NCM processes is essential to the productivity and profitability of the company. In this research work, the NCM process selection problem is addressed using CRITIC (criteria importance through inter-criteria correlation) and CODAS (combinative distance-based assessment) multicriteria decision-making methods. The successive integration of CRITIC and CODAS makes the computational methodology simple yet effective for use in NCM process selection problems. A case study is conducted to assess the performance of proposed approach while selecting the best NCM process for machining titanium from the eight most often used NCM processes, namely, AJM (abrasive jet machining), USM (ultrasonic machining), CHM (chemical machining), EBM (electron beam machining), LBM (laser beam machining), ECM (electrochemical machining), EDM (electrodischarge machining), and PAM (plasma arc machining). Material removal rate, shape feature, work material type, tolerance and surface finish, power requirement, and cost are the criteria used to evaluate and pick the best NCM process. The criteria are weighted using the CRITIC method. Based on the criteria stated, PAM is proven to be the best possible NCM process for machining titanium, followed by EBM. The acquired results are compared to the results of previous studies and found to be in good accord.