Validation Case: Backward Extrusion

Metal Forming Backward Extrusion Cold Forming Multi-Stage

This case is reserved for a backward extrusion validation sequence with demanding contact and confined material flow. It is a strong benchmark for checking tool interaction, cavity filling, and deformation history across multiple forming stages.

Reference paper

The Numerical Study on the Multi-Stage Cold Forming Process of Hexalobular Socket Torx Nuts

Chih-Cheng Yang, Jian-Qing Lu, Hsiu Ying Tsai, Jhonel Cortez Andres

Department of Mechanical and Automation Engineering / Graduate School of Mechatronic Science and Technology, Taiwan Steel University, Taiwan

This paper will be the anchor reference for the backward extrusion case. Once you send the benchmark text, this page can be expanded with the stage-by-stage description, material data, forming loads, and geometry comparison.

Model setup

  • The billet material is modeled with a Hollomon law.
  • Material parameters are A = 386.796 MPa and n = 0.154.
  • The plastic strain range used for the law is eps in [0, 0.65].
  • For strains above 0.65, the flow stress is assumed constant.
  • The benchmark is solved as a 2D axisymmetric model.
  • A maximum element size of 0.2 mm was used in the tested mesh.

What this benchmark checks

  • Material backflow into the punch-controlled cavity
  • Load evolution through multiple stages
  • Severe contact with changing interface conditions
  • Geometric accuracy of the final cold-formed part

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