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The time has come for natural fibres to stand as potent substitutes for synthetic fibres in various industrial applications. Recently, jute fibre is being used as reinforcement material in the development of reinforced plastics for various engineering products. The production cycle of a composite product often necessitates certain degree of machining operations. Drilling is one of the most widely practised machining operation for making holes in composite laminates. Hole making is imperative to ascertain the assembly of intricate composite products. The literature available indicate that not much research work has been reported on the machining behaviour of jute fibre-reinforced polypropylene composites. Hence, in the present experimental endeavour, drilling of woven jute fabric-reinforced polypropylene composite has been performed. The effect of operating variables on thrust force and torque signals was investigated. Drilling-induced damage in the developed composite was quantified using stereo microscope. The experimental values indicate close relationship between the tool geometries and the delamination factor. SEM analysis was also conducted to understand the drilling behaviour and surface morphology of the drilled holes. Among the solid drills compared, parabolic drill reveals better cutting behaviour in terms of lower drilling forces and better quality of holes. This may be attributed to the better tool-work piece interaction in case of parabolic drill point geometry.

PurposeTaguchi's technique is best suited to optimize a single performance characteristic yielding an optimal setting of process parameters. A single setting of process parameters may be optimal for one quality characteristics but the same setting may yield detrimental results for other quality features. Thus the purpose of this paper is to describe simultaneous optimization of multi‐characteristics.Design/methodology/approachThe multi‐machining characteristics have been optimized simultaneously using Taguchi's parameter design approach and the utility concept. The paper used a single performance index, utility value, as a combined response indicator of several responses.FindingsA simplified model based on Taguchi's approach and utility concept is used to determine the optimal settings of the process parameters for a multi‐characteristic product. The model is used to predict optimal settings of turning process parameters to yield the optimum quality characteristics of En24 steel turned parts using TiC coated carbide inserts. The optimal values obtained using the multi‐characteristic optimization model have been validated by confirmation experiments. The model can be extended to any number of quality characteristics provided proper utility scales for the characteristics are available from the realistic data.Practical implicationsThe proposed methodology can be applied to those industrial situations where a number of responses are to be optimized simultaneously.Originality/valueThe paper discusses a case study on En24 steel turned parts using titanium carbide coated tungsten carbide inserts. The material, En24 steel, has wide applications in aerospace, machine tools, automobiles, etc. The proposed algorithm is easy to apply.