Investigations on multi-sheets single point incremental forming of commercial pure titanium alloys

The rate of production in single point incremental forming (SPIF) approach for the sheet metals is comparatively low when comparing to multiple sheet incremental forming process (MSSPIF). This increase in production rate comes with a trade-off of reduced formability in MSSPIF. The aspiration of the current paper is to analyze the formability, the strain distribution, and the void coalescence variables as per the strain triaxiality εmεeff during the MSSPIF process of the available commercially pure (CP) titanium sheets. The forming limit diagrams (FLDs) and the strain distribution analysis have been carried out for multiple sheets of two, three, and four sheets bunch while they were formed together. The outcomes proved that the uppermost sheets achieved the higher limiting principal true strain and the limiting values of the principal true strain of bottom sheets decreased in accordance with the position of the sheet and the same was reported in FLDs. The void coalescence in the fractured specimen exhibited an enhanced fracture resistance for CP sheets of titanium. The size of void (µm), thickness of ligament (LT), void (L/W) ratio, d-factor, strain triaxiality, and other void coalescence parameters also have been compared when two, three, and four sheets were formed together during MSSPIF process.