Development of Incremental Diaphragm Forming Method

Incremental forming is suitable for the low-volume production of various products and has potential aerospace applications. However, it causes significant plate thinning due to its ironing and leaves tool marks. To address this, we developed an incremental diaphragm forming method using a hemispherical shape and a Steel Plate Cold Commercial (SPCC) diaphragm. This approach suppressed thickness reduction and tool mark formation effectively. Experiments using the 0.81 mm thick Al alloy 2024-T3 showed forming limits around 45° in conventional incremental forming, whereas using a 1 mm SPCC diaphragm extended forming to 50°, despite some wrinkling. Thickness reduction was kept within 5%, and thickness slightly increased beyond 40°, suggesting thinning suppression through drawing. Tool marks were eliminated by diaphragm surface transfer, and surface roughness remained comparable to that attained by conventional incremental forming, demonstrating the method’s effectiveness in improving workpiece quality.