A hat-shaped member was prepared by press-forming continuous-fiber carbon-fiber-reinforced thermoplastics (CFRTPs) by locally heating the area of bending deformation and the area of interlaminar slip between the inner and outer surfaces of the laminate to prevent fiber wrinkling. In this study, we examined whether preheating the hat top below the melting point and embossing it at the same time as press forming can prevent the buckling of the fibers that could not be removed previously. The effect of embossing on product strength was verified by three-point bending tests and numerical analysis. As a result, the forming of dimples or beads improved the gripping force, and drawing in the excess fibers prevented the wrinkling of inner R fibers. Strength tests showed that bead-formed sheets with a fiber direction of 45 deg had the same strength and stiffness as the sheet. Analysis results showed that the interlayer adhesion of the embossed area was reasonably good.

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.