The effects of vertical increment on surface quality and taper wall angle on formability during single point incremental forming (SPIF) of S235 steel sheets: experimental and integrated finite element analysis

Single Point Incremental Forming (SPIF) presents a cost-effective alternative to traditional sheet metal forming, particularly for prototyping and small batch production. This study examines how process parameters affect the quality and capabilities of SPIF when forming S235 steel sheets. Using a CNC milling machine equipped with a test bench specially designed for incremental sheet metal forming, wemainly studied the effect of two process parameters: tool increments a long the Z axis and sheet angle, while measuring surface finish andmaximum forming depth. Numerical simulations complemented thephysical experiments in order to validate the results. The results reveal important practical information: smaller vertical steps produce smoother surfaces, while larger wall angles significantly reduce the depth to which the sheet metal can be formed before cracking.It should be noted that the best balance between surface qualityand formability was achieved with specific combinations of parameters.The research demonstrates that SPIF can be implemented effectively using standard CNC equipment, making this technology more accessiblefor industrial applications. These results provide clear guidelinesfor manufacturers wishing to adopt SPIF for steel components, whichcould reduce prototyping costs and lead times. At the end mathematicalmodels developed from the experimental data enable quantitativeprediction of surface roughness and maximum forming depth for given process parameters.