サブナノ秒レーザーピーンフォーミングによる薄板の球面成形

抄録

Laser peen forming is a die-less noncontact incremental sheet metal forming technique using laser-induced shock waves. The author applied sub-nanosecond laser peen forming to aluminum sheet forming and attempted to obtain a spherical shape. The process requires laser scanning and is often affected by the scanning method used. The author adopted some spiral scanning and processed several rectangular aluminum sheets. The formed shapes were varied by using different strategies of spiral scanning. A superior spherical shape was obtained by spiral scanning progressing from the inner to the outer side of a workpiece. Laser peen forming shows several deformation modes according to the depth of the plastic deformation zone generated by shock waves. The effects of deformation modes on spherical forming were examined. A deformation mode that generated a large elongation but a small bending was favorable for large-curvature and precise spherical shape formation. The effects of scanning parameters on spherical forming efficiency were examined under constant coverage. Scanning with small pitch and high velocity was favorable. However, the advantage of high scanning velocity had an upper limit.