Effect of single-point incremental forming process parameters on roughness of the outer surface of conical drawpieces from CP titanium sheets

With the widespread use of numerically controlled machine tools, single-point incremental forming (SPIF) process has enjoyed growing interest in the industry. This article presents the results of research on the influence of forming process parameters (step size, tool rotational speed, feed rate and forming strategy) on the roughness of the outer surface of conical drawpieces with a slope angle of 45° from commercially pure titanium sheets. The following variable process parameters were used: tool rotational speed varied from –600 to 600 rpm, feed rate varied from 500 to 2000 mm/min and step size varied from 0.1 to 0.5 mm. The SAE 75W85 synthetic gear oil was used as lubricant. Two basic roughness parameters were analyzed: the mean roughness Sa and the maximum height Sz. The influence of SPIF parameters on surface roughness was analysed using multi-layer artificial neural networks. It was found that reducing the feed rate with the climb strategy causes a decrease in the average roughness Sa. The opposite relationship was observed when forming according to the conventional strategy. At low tool feed rate (500 mm/min), reducing the step size caused an increase in the Sz parameter. At high tool feed rate (2000 mm/min), the effect of the step size is negligible.