Youjuan Ma

Forming Properties of a Microscale Laser Dynamic Flexible Forming Technique

Microscale laser dynamic flexible forming (µLDFF) is a novel micro-forming process. Laser-induced shockwaves act on the soft punch to deform the metal foils. In this article, the forming properties of the µLDFF process are studied from four angles, namely, the maximum deformation depth, accuracy, thickness thinning ratio, and surface quality. The maximum deformation depth of the samples formed under different laser energies was measured. The 2D profiles of the workpieces were measured to study the accuracy. The results show that the deformed samples replicated the mold features well. The cold-mounted technique was used to measure the thickness of the deformed metal foils along the cross section and to discuss the thickness thinning ratio. The results show that µLDFF can reduce localized necking and stress concentrations effectively. The surface roughness was characterized to study the surface quality of the workpieces, and the results indicated that the deterioration of the formed surface was weakened during µLDFF. The advantages of the ultrahigh strain rate and soft punch are both presented in the µLDFF process, which is favorable for fabricating micro components.

An Experimental Study on Micro Clinching of Metal Foils with Cutting by Laser Shock Forming

This paper describes a novel technique for joining similar and dissimilar metal foils, namely micro clinching with cutting by laser shock forming. A series of experiments were conducted to study the deformation behavior of single layer material, during which many important process parameters were determined. The process window of the 1060 pure aluminum foils and annealed copper foils produced by micro clinching with cutting was analyzed. Moreover, similar material combination (annealed copper foils) and dissimilar material combination (1060 pure aluminum foils and 304 stainless steel foils) were successfully achieved. The effect of laser energy on the interlock and minimum thickness of upper foils was investigated. In addition, the mechanical strength of different material combinations joined by micro clinching with cutting was measured in single lap shearing tests. According to the achieved results, this novel technique is more suitable for material combinations where the upper foil is thicker than lower foil. With the increase of laser energy, the interlock increased while the minimum thickness of upper foil decreased gradually. The shear strength of 1060 pure aluminum foils and 304 stainless steel foils combination was three times as large as that of 1060 pure aluminum foils and annealed copper foils combination.