Design and validation of a fixture for positive incremental sheet forming. (March 2018)

• Record Type: Journal Article
• Authors: Siddiqi, Muftooh Ur Rehman; Corney, Jonathan R; Sivaswamy, Giribaskar; Amir, Muhammad; Bhattacharya, Rahul
• Is Part Of: Proceedings of the Institution of Mechanical Engineers. Volume 232:Number 4(2018)
• Page Start: 629
• Page End: 643
• Publication Date: 2018-03
• Subjects: Incremental sheet forming -- fixture design -- sheet thickness -- sheet strains; Mechanical engineering -- Periodicals; Engineering -- Management -- Periodicals; Manufacturing processes -- Periodicals; 629.8
• DOI: 10.1177/0954405417703423
• Languages: English
• ISSNs: 0954-4054

Abstract

Incremental sheet forming is an emerging manufacturing technique in which sheet metal is formed into desired shape through the application of localized force using a hemispherical tool. Potential advantages of the process are its relatively low cost and small lead times, and these have to be balanced against the disadvantages of low dimensional accuracy and a limited understanding of the process' internal mechanics. Incremental sheet forming system can be classified as positive, or negative, depending on whether the sheet material is progressively deformed onto a protrusion or a cavity. In negative systems, the work piece is held on a static fixture; whereas, in positive incremental sheet forming, the fixture must be incrementally lowered onto a protruding die. Although the vertical movement of positive incremental sheet forming fixtures is easily illustrated schematically, its implementation is challenging; if the descent is actuated, the motion has to be carefully coordinated with those of the forming tool; if free sliding on vertical columns, the rig must move without jamming or rocking. This article reports the development and testing of a positive incremental sheet forming fixture design that uses nylon sleeve bushes. Symmetric and asymmetric components were formed using the designed fixture, modular wooden dies and a rotating tool with multiple diameters and the results are discussed.