Overview on massive forming processes, future and their challenges

Abstract

The massive shaping processes (forging, rolling, extrusion, wire and bar drawing) play an important role to fabricate metal products. These forming processes undergo plastic deformations of the metal and acquire required shapes and sizes by application of suitable stresses such as tension, compression and shear. Thus due to the characteristics such as cost effectiveness, good mechanical properties of the product, flexible operations, higher productivity, no wastage of the raw material and faster production rate, the work on metals in effective way becomes highly important. Bulk forming and severe deformation process result in massive shape change. The surface area-to-volume of the work is relatively small and mostly done in hot working conditions. The broad topic of bulk metal forming includes many processes both as classical and modified categories. These classical bulk metal forming processes are still in great demand in many industry sectors. It does not seem that this trend will slow down as new technologies have been developed over recent years. These technologies are continuously modified for new demands, such as higher precision (near-net shape) forming, micro-/nano-forming for micro-components, and bulk-sheet metal forming processes for complex workpieces. Thus, it is important to have a broad knowledge of the classical theories of metal forming which was mainly an overview of metal forming processes and their fundamentals. With the growing competitive industrial vibe, it is important to develop into cost-effective production processes. Especially for some automotive components, it is suggested to incorporate bulk metal forming processes into sheet metals to produce high-quality sheet metal components commercially. Sheet-bulk metal forming (SBMF) processes are defined as sheet metal forming where the flow occurs in three dimensions similar to bulk metal forming. After computer-aided design of the tool geometry, the bulk metal forming tools are usually fabricated by machining processes. The main die manufacturing process may be divided into die design, rough machining, heat treatment, finish machining, manual finishing (polishing), or benching and hard coating. The main characteristic of these processes is that the final product has the dimensions of a magnitude similar to the sheet thickness, projecting out of the plane of the sheet. Based on this characteristic, only some special bulk forming processes can be applied on sheet metals. In this review paper, the authors describe the working of various types of bulk metal forming processes, historical development, importance, future scope and challenges, so that this paper may serve as a good reference for forming process selection and identification for researchers, engineers and students.