Microforming: Experimental investigation of the extrusion process for micropins and its numerical simulation using RKEM

Jian Cao*, Neil Krishnan, Zhong Wang, Hongsheng Lu, Wing K Liu, Anthony Swanson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

111 Scopus citations


Microforming using a small machine (or so-called desktop machine) is an alternative new approach to those using full-size heavy equipment for manufacturing microparts. Microparts are commonly defined as parts or structures with at least two dimensions in the submillimeter range, which are used extensively in electronics and micromechanical products. However, when scaling down a conventional forming process to microscale, the influence of the so-called size effect needs to be considered. The individual microstructure (size, shape, and orientation of grains) and the interfacial conditions show a significant effect on the process characteristics. In this paper, the process of extrusion is investigated to establish it as a viable process for microforming. A forming assembly is fabricated and used in conjunction with a loading substage to extrude micropins with a final diameter of 1 mm. The effect of grain size is investigated by using workpieces heat treated to produce grain sizes varying from 32 fun up to 211 μm. Two extrusion dies with different roughness are used to study the effect of surface finish. While experiments lead to interesting questions and new discoveries, theoretical or numerical solutions are necessary tools for process optimization. Here, knowing the limits of the current widely used numerical simulation tools [i.e., the Finite Element Method (FEM)], a new method, the Reproducing Kernel Element Method (RKEM), has recently been developed to address the limitations of the FEM (for example, remeshing issue), while maintaining FEM's advantages, e.g., the polynomial reproducing property and function interpolation property. The new RKEM method is used to simulate the microextrusion problem. Its results are compared with that obtained from the FEM and the experiment result. Satisfactory results were obtained. Future directions on the experimental and simulation work are addressed.

Original languageEnglish (US)
Pages (from-to)642-652
Number of pages11
JournalJournal of Manufacturing Science and Engineering, Transactions of the ASME
Issue number4
StatePublished - Nov 1 2004

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Mechanical Engineering
  • Computer Science Applications
  • Industrial and Manufacturing Engineering

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