Direct observation now possible with x-rays from SPring-8 — RCAST, the University of Tokyo succeeds in x-ray diagnosis of metal machining processes

Currently, improvements to machining processes on factory floors rely on professional-level know-how, making theoretical analysis difficult and simulation tools rarely used. This is because metal machining processes take place inside the metal itself or within coolant fluids, making direct observation impossible.

Professor Hidekazu Mimura from the Research Center for Advanced Science and Technology (RCAST) at the University of Tokyo, Group Director Makina Yabashi from the RIKEN SPring-8 Center, and Section Head Haruhiko Ohashi from the Japan Synchrotron Radiation Research Institute (JASRI) have developed an ultra-high-speed X-ray diagnostic method for metal machining technologies, including cutting and electrical discharge machining. Their results were published in Review of Scientific Instruments.

Using newly developed, highly penetrating 100 keV bright X-rays from SPring-8, the team achieved a world-first: directly observing the process of metal removal by a tool inside both the coolant fluid and the metal itself during drilling, at the ultra-high speed of 1/5,000th of a second. In addition, the vibration behavior of the drill tool was captured, revealing the mechanism behind burr formation, a defect that must be prevented during hole machining. The team also succeeded in observing electrical discharge machining, which is of great importance in industrial applications.

This technique now makes it possible to directly observe phenomena occurring inside coolant water and metal that were never visible before, including the metal removal process, chip formation, and tool vibration.

When SPring-8-II is completed in two years, ultra-high-speed X-ray diagnosis of all kinds of metal processing—including cutting, electrical discharge machining, laser machining, and 3D printing—will become possible with even higher spatial and temporal resolution. The ultra-high-speed X-ray diagnostic method for metal machining processes developed by the team is expected to dramatically accelerate the development of machine tools and implements, and to contribute to the further advancement of the machine tool sector, a field in which Japan holds a leading position.

Journal Information
Publication: Review of Scientific Instruments
Title: High-speed imaging of cutting and electrical discharge machining (EDM) in thin metals and fluids using high-intensity 100 keV x rays
DOI: 10.1063/5.0279761