Hole Expansion Ratio (HER) Testing Setup

This is an integrated setup designed to adapt to universal load frames and hydraulic presses in order to enable complete Hole Expansion Ratio (HER) testing of sheet metal samples. This is a complete kit that encompasses the mechanical testing components to perform hole expansion, as well as a dedicated mi-Sensor (configured for HER) to track the edge of the HER sample up to fracture (crack detection both in-situ and ex-situ). This setup enables complete and accurate hole expansion ratio (HER) testing while utilizing existing load frames and testing equipment (without the need for a dedicated HER tester).

General Specifications:

  • Adaptability: Most universal load frames (20kN or higher) with modern electronics and an I/O card (INSTRON, ZwickRoell) as well as most servohydraulic presses (Interlaken)
  • Max.Force: ~20kN
  • Max. Sheet Thickness: ~2.5mm
  • Max Test Speed: 0.25 mm/s (in-situ) & 1mm/s (ex-situ)
  • Punching Direction: NA
  • Gripping:
    • Manual: 20-50kN
    • Hydraulic: 20-50kN


  • Very economical option to perform HER testing and enables utilization of existing load frames
  • Adaptation to Electromechanical load frames offers better control of the test speed (when compared to hydraulic machines)
  • Can accommodate sheet samples with different thicknesses (~0.6mm to ~2.5mm)
  • Easy to use and robust optical tracking system to enable crack detection in real-time mode, as well as image processing in an ex-situ mode (mi-Sensor HER configuration with A.I.).
  • Optical tracking system enables accurate and repeatable tracking of the growing hole diameter (including automatic measurement of the HER value and springback compensation) (tested on a wide range of materials)
  • Optical tracking system enables accurate and repeatable crack detection (tested on a wide range of materials)

HER Testing Setup in Use: