Hand–Arm Vibrations and HFMI
High‑Frequency Mechanical Impact (HFMI) inherently produces vibration because the process relies on repeated local impacts at the weld toe. This is a known drawback. The practical questions are: how large is the vibration exposure in real work, and how can we minimize the risk? Real‑World vs. Declared Vibration Values A key limitation is that declared vibration values for hand‑held tools—measured in laboratories according to EN ISO 28927—do not fully describe actual hand–arm vibration (HAV) exposure during real work. Laboratory type‑tests are conducted under standardized conditions (ideal posture, controlled feed force, new components, consistent loading). In contrast, field use involves higher grip forces, variable working positions, and harder or uneven materials—all of which affect the vibration transmitted to the operator. Across field measurements on percussive pneumatic tools (e.g., chipping hammers, riveting hammers, impact scalers), real‑world vibration magnitudes often measure
8 March 2026
