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The plunger part in temporary electronic connectors is traditionally fabricated by micromachining. Progressive forming of microparts by directly using sheet metals is developed and proven to be an efficient microforming process to overcome some intrinsic drawback in realization of mass production of microparts. By employing this unique micromanufacturing process, an efficient approach with progressive microforming is developed to fabricate plunger-shaped microparts. In this endeavor, a progressive forming system for making microplungers using extrusion and blanking operations is developed, and the grain size effect affected deformation behaviors and of surface qualities of the microformed parts are studied. The knowledge for fabrication of plunger-shaped microparts via progressive microforming is developed, and the in-depth understanding and insight into the deformation behaviors and tailoring the product quality and properties will facilitate the design and development of the forming process by using this unique microforming approach.

In the last decade, the concept of progressive microforming has emerged and developed gradually, which is considered as an efficient and promising method to fabricate the micro-scaled part. Micro-cylinder parts, micro-flanged part, and multi-flanged microparts are representative micro bulk parts by the progressive microforming system using sheet metal. In these cases, many efforts focus on the forming process, such as microblanking and microextrusion. Meanwhile, the quality of the fabricated parts also attracts attention. In this paper, an intensive review on the development of progressive microforming technologies and the formed parts is presented, and the influence of size effect to dimensional accuracy, material flow, geometrical feature, and fracture is also discussed.

Monolithic aluminium alloy parts are highly required in aeronautical industry, but they show signi cant geometrical distortion after the machining process. This work investigated the distortion attributed by the initial residual stress of raw material and the machining induced residual stress during the milling process, as well as explored the effects of the machining toolpath strategy. Single-/multi-pocket parts were milled from 7050-T7451 aluminium blocks with different initial residual stress, and an element deletion method was developed for numerical study to simulate different sequences of material removal.It was revealed that the toolpath parallel to the long side of block caused more distortion on the side surfaces of nal part. The value of distortion was positively correlated to the magnitude of initial residual stress of raw material. The simulation results indicated that the distortion attributed by machining induced residual stress accounted for about 15% of nal distortion. The nding promotes the design optimization of machining monolithic parts by minimizing distortion, thereby bene tting the application of large monolithic parts in industry.