A Review on Micro/Nanoforming to Fabricate 3D Metallic Structures

Abstract

With the rapid development of micro‐electromechanical systems (MEMS), micro/nanoscale fabrication of 3D metallic structures with complex structures and multifunctions is becoming more and more important due to the recent trend of product miniaturization. As a promising micromanufacturing approach based on plastic deformation, micro/nanoforming shows the attractive advantages of high productivity, low cost, near‐net‐shape, and excellent mechanical properties, compared with other non‐silicon‐based micromanufacturing technologies. However, micro/nanoforming is far less established due to the so‐called size effects in terms of materials models, process laws, tooling design, etc. The understanding of basic issues on micro/nanoforming is not yet mature, and it is currently a topic of rigorous investigation. Here, a systematic review on the micro/nanoforming processes of 3D structures with multifunctional properties is presented, wherein also a critical examination of the interplay between relevant length scales and size effects affecting the structural integrity of micro/mesoscale metallic systems is also provided. Finally, the challenges of micro/nanoscale fabrication are proposed, including the development trends of new micro/nanoforming processes, multiple field coupling effects, and theoretical modeling at the trans‐scale.

Forming limit curves of ultra-thin sheet metal for high-speed Nakajima test

“…Both the experiment and numerical simulations shows a signi cant in uence of the size effect on the cracking character as the dimensions down to micro level. The forming limit curve shifts downwards with the decreasing thickness grain size ratio [9,10]. However, the deformation properties of ultra-thin sheet metal at high strain rate are different from that at quasi static strain rate.…”

Geometrical and microstructural size effects in meso-/micro-scaled progressive forming by directly using metal wires

“…Therefore, the meso-/micro-forming, i.e., the plastic processing technology applied in the meso/micro-eld, has been serving as an effective fabrication method for the mass production of meso-/micro-scaled metallic parts [5,13]. Compared with other manufacturing processes, the meso-/micro-forming technology possesses outstanding advantages of quite high productivity rates and e ciency besides good product quality, low production cost, less material waste, net-shape or near-net-shape characteristics [14,15]. However, when the target parts are designed with multi-features or complex-structures, the production rate and e ciency of such technology are limited by the problems of feeding, transporting and picking up of billet and nal parts in forming process [16].…”

Deformation Behavior and Microstructural Evolution of T-Shape Upsetting Test in Ultrafine-Grained Pure Copper

“…The sharp rise of Micro System Technology (MST) and Micro Electro Mechanical Systems (MEMS) has driven the current industrial development towards miniaturization even microminiaturization [1]. Compared with Micro-machining, Laser technology, LIGA technology and micro electro-discharge machining, metal plastic deformation has greater advantages in terms of cost control, processing efficiency and dimensional accuracy control [2,3], thus promoting the industrialization of micro-formed parts.…”