International Journal of Engineering, Management & Sciences (IJEMS) ISSN: 2348 –3733, Volume-2, Issue-1, January 2015
Multi- Objective Optimization of Forging of an Automotive Component Ajit Kumar, Avinaw Pratik, Ashutosh Kumar Abstract— Various process parameters such as Die temperature, Billet temperature, Flash thickness and Flash width affect the forging process differently, thus the optimization design of process parameters is necessary to obtain a good product. In this paper an optimization method for the connecting rod closed die forging is proposed based on the finite element method (FEM) and Taguchi method with multi-objective design. Preform design in forging processes is an important aspect for improving the forging quality and decreasing the production cost. Utilization of designing & simulation tool can reduce iterative & time consuming approaches. The objective of this paper is to obtain an optimal preform shape in the consideration of the influence of the metal flow deformation in closed die forging process. The goal of the simulation and optimization process is to minimize the forging load and produce defect-free forgings. The optimal shape of the billet that gives minimum forging load with complete die filling was obtained after several optimization iterations. Optimization of die temperature, billet temperature, flash thickness & flash width will be performed by DEFORM-3D. Die filling & less wear in the dies will be the required achievements. MINITAB15 software is used for the calculation of S/N ratio & graphs for optimization. Index Terms— DEFORM 3D, Finite element method, Hot die forging, Preform, Taguchi method.. I. INTRODUCTION
Metal forging technology plays an important role in manufacturing industry. Most of forging processes are very complex. Two or more forging stages are usually used to realize a sound final forging process design [1]. The automobile engine connecting rod is a high volume production, critical component. It connects reciprocating piston to rotating crankshaft, transmitting the thrust of the piston to the crankshaft. Every vehicle that uses an internal combustion engine requires atleast one connecting rod depending upon the number of cylinders in the engine. As the purpose of the connecting rod is to transfer the reciprocating motion of the piston into rotary motion of the Crankshaft [2]. Connecting rod is widely applied as an important component in most of the mechanical and automotive industry. In recent years, there has been an increased interest in the production of Connecting rod by the precision forming technique. This is because of their inherent Manuscript received January 09, 2015. Ajit Kumar, Foundry-Forge Technology, NIFFT RANCHI, RANCHI, India, Avinaw Pratik, Foundry-Forge Technology, NIFFT RANCHI, RANCHI, India, Ashutosh Kumar, Foundry-Forge Technology, NIFFT RANCHI, RANCHI, India,
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advantages compared with conventional methods. The advantages include the excellent mechanical properties, less raw material, good tolerance, high productivity and cost savings. The precision forging of the Connecting rod is very complicated and various process parameters such as deformation temperature, punch velocity and friction affect the forming quality differently, thus the reasonable process parameter design is very important. Actually, for lack of theoretical instruction, the process parameters of Connecting rod precision forging were determined by repeated experiments with artificial experience, which consume a large amount of materials and time. As a result, the optimization of process parameters is significant to obtain the desired goals such as achieving good die fill quality, reducing the forging force, increasing the die life, obtaining favorable grain size [3]. Mechanical presses are displacement-restricted machines. Mechanical forging press provides opportunity for consistent forging results and offers high productivity and accuracy without requirements for special operator skills. Mechanical presses are replacing hammers in ever increasing numbers, not only because of environmental problems, but also because, in most circumstances, mechanical press forging is less costly than hammer forging [4]. The Finite Element Method (FEM) offers the possibility to design the entire manufacturing process on a computer. This leads to a reduction of the cost and time in process and tool design, tool manufacturing, and die try-out. In addition, it is possible to iteratively modify the process conditions in the simulation to find the best manufacturing conditions for a product [5]. Connecting rods are subjected to forces generated by mass and fuel combustion .These two forces results in axial load and bending stresses. A connecting rod must be capable of transmitting axial tension, axial compression, and bending stress caused by the thrust and full of the piston and by centrifugal force. Finite element (FEM) Model is a modern way for fatigue analysis and estimation of the component [6]. DEFORM 3D are capable of coupled modelling of deformation and heat transfer for simulation of cold, warm or hot forging process, Information on material flow, die fill , forging load, die stress, defect formation, Extensive material database for many common alloys including steel, aluminium, titanium and super alloys [7,10]. Computer modelling and optimization are used to significantly reduce time and costs of process design and to optimize the final material state. The ultimate goal of computer modelling in the forging process is to reduce procurement times from as much as 30 months to as little as 2 months with associated reductions in costs and defects[8]. The closed die forging process is often used to manufacture high quality mass production parts like connecting rods, crankshafts etc at moderate costs. In principle, forging operations are non-steady state processes,
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