Single-point incremental forming of AA6061 aluminum alloy at elevated temperatures

Single-point incremental forming (SPIF) is a flexible and affordable process suitable for small-batch customized productions. Typically, metal alloys with a high strength-to-weight ratio exhibit a low formability at room temperature. The feasibility of conducting the SPIF process on these alloys at high temperatures is in demand. In this study, the SPIF process of the AA6061 aluminum alloy sheet at the temperature range of 25–400 °C is experimentally and numerically investigated. In this regard, a fixture was designed and fabricated to perform the SPIF process using heating cartridges for warming up the sheet metal homogenously. The effect of the temperature, the vertical pitch, the feed rate, and the lubrication type on the formability of the AA6061 sheet in SPIF of a truncated cone was studied. According to the results, by increasing the forming temperature from 25 to 400 °C, the formability of the truncated cone with the wall angle of 60° is improved by 528%. Moreover, using an appropriate combination of the process parameters, a truncated cone with a wall angle of 65° can be successfully formed up to the forming depth of 44 mm with a formability enhancement of 642% compared to the cold SPIF. For further understanding of the mechanics behind this improvement, the influence of the temperature on the formability was numerically studied. It was observed that the vertical pitch and the lubrication type have a significant interaction effect on the maximum achievable forming depth and the surface finish. It was also concluded that the effect of the feed rate on the formability is negligible for the considered range of the process parameters.