Progressive microforming process: Towards the mass production of micro-parts using sheet metal

Ehsan Ghassemali, Ming Jen Tan, Anders E.W. Jarfors, S. C.V. Lim

Research output: Contribution to journalArticleResearchpeer-review

44 Citations (Scopus)


Although there is considerable published literature on micro-metal forming processes, there is still a lack of research towards implementing these processes commercially. Some of the challenges are handling of micro-parts and process intermittency. This work demonstrates the feasibility of producing symmetric micro-parts using a progressive forming set-up. Such a progressive forming process alleviates the challenges in handling and removal of micro-parts. Micro-pins with diameters of 0.3, 0.5, and 0.8 mm were successfully manufactured without defects. Experimental observations together with process simulation results showed that this process has three main stages: (1) indentation at the very beginning, (2) upsetting, and (3) extrusion predominantly occurring at the very end stage of the stroke. The bulk of the pin forming occurs at the end stroke of the process (extrusion stage). The effects of punch/pin diameter ratio on the pin aspect ratio and the maximum forming load were also investigated. In addition, the finite element results also revealed that a hybrid friction model was required to be implemented for better fit with experimental results as compared to the shear and Coulomb friction models.

Original languageEnglish
Pages (from-to)611-621
Number of pages11
JournalInternational Journal of Advanced Manufacturing Technology
Issue number5-8
Publication statusPublished - May 2013
Externally publishedYes


  • Extrusion
  • Hybrid friction model
  • Micro-pin
  • Microforming
  • Progressive forming

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