Parametric evaluation on surface integrity of Titanium Grade 5 sheets formed by Single Point Incremental Forming

This study presents a comprehensive experimental investigation into the surface integrity of Titanium Grade 5 alloy sheets formed using the Single Point Incremental Forming (SPIF) process. Key surface characteristics, including surface roughness, topography, induced residual stresses, and corrosion behaviour under simulated body fluid, are systematically analysed. Titanium alloys in sheet metal form are extensively used in biomedical engineering as implants due to their superior strength-to-weight ratio and excellent corrosion resistance. SPIF is a die-less sheet metal forming technique in which material is progressively deformed into the desired shape through controlled tool movements on a CNC machine or robotic system. The process offers high flexibility in producing complex geometries and allows modification of surface characteristics through process parameter control. In this work, the effects of critical forming parameters—namely tool rotational speed, feed rate, tool diameter, incremental forming depth, forming angle, forming size and lubrication conditions—on surface integrity were examined at various levels. The results reveal that these parameters influence surface characteristics though at varied rates. Lubricating conditions during forming, tool speed and incremental depth are the most critical parameters influencing the surface integrity of the formed sheets. The current work gives insights for optimizing SPIF process parameters to achieve desired surface quality in the formed Titanium Grade 5 sheets.