Formability of Aluminum Alloys During Single Point Incremental Forming: A Review

Introduction

In the eternity of today’s renovation and improvement, the superiority of custom-built merchandise in terms of quality, cost, rapid prototyping and short lead times is turning into a problem of central importance. The materials with high thermal strength, lightweight, excellent corrosion and creep resistance, high fatigue strength, high stiffness, etc. are needed. Aluminum alloys possess all of these properties which make them suitable for most of the industries. Due to these confines, highly flexible forming processes are desired. There are numerous sheet metal forming methods like Deep Drawing, Progressive and Transfer Die Forming, Spinning, High-Velocity Forming, Shear Forming, Stamping, and Incremental Sheet Forming (ISF), etc. (Schedin, 1992). The welfares of ISF processes in terms of formability, easiness in tooling, and dieless set-up have permitted the application of the process for manufacturing geometrically intricate and tailor-made parts. ISF fulfills and justifies all the above requirements with reasonable expenses. ISF was first coined and patented by Edward Leszak in Sept. 1967 (Leszak, 1967), ISF is of two types, namely negative (concave) or SPIF and positive (convex) or TPIF. In a negative sheet forming the blank is formed into the support or rig but in a positive sheet forming in addition to the tool, there is additional supportive die (partial or full die) is used (Katajarinne & Kivivuori, 2013). Japanese researcher, Iseki in 1989 done revolutionary work by using a 3-D CNC milling machine for ISF and introduced the first single point incremental sheet forming (SPIF) (Figure. 1a). Two point incremental forming (TPIF) (Figure. 1b) was first introduced by Mastubara (1994) (Emmens et al., 2010).

Figure 1.

Pictorial explanation of (a) setup for SPIF; (b) setup for TPIF

Originally, SPIF was developed as a manufacturing process used for the production of metallic parts (Jeswiet et al., 2005), however, continuous development of SPIF makes it suitable for polymers (Martins et al., 2009), shape-memory materials (Mohammadi et al., 2015), and composite materials (Conte et al., 2017). The process has been reviewed in a current decade (Joost R. Duflou et al., 2018; Echrif & Hrairi, 2011; Li et al., 2017) but there is a lack of review article specially on single point incremental formability of aluminum alloys was noticed and require benchmark work to realize full-scale industrial use of the process for partial and complete forming of aluminum alloys. Considering the extensive knowledge transfer, as reflected by the enormous number of researches over the previous decade and the exhibited applications, the authors have united to incorporate an updated review of the cutting edge in the area SPIF of aluminum alloys. The review is organized by investigating the adequate quantity of research articles in various aspects especially to cover present applications of SPIF process in forming aluminum alloys of different grades, the fundamental knowledge and prerequisites for the process apparatus, forming principle, and important process parameters followed by the critical investigation of process parameters effect on formability of aluminum alloys in the SPIF process. The review is concluded with, the application territories of the SPIF process to deliver the present and future regions of research.

Fundamentals Of Spif

In modern industrialization, incremental forming offers various opportunities for design engineers and producers, as dies are considered as major obstacles in automation process. Conventional forming processes are costlier than SPIF because they need a dedicated die, hydraulic press and long setup time. These benefits of SPIF attracted research scholars and industry persons more towards its technique.