Magnescale Products

When we demanded environmental resistance and high accuracy, we arrived at magnetism.

The history of Magnescale, which is also the company name, begins with the invention of the magnetic flux-responsive magnetic head in 1965 by Sony’s Miyoshi Uemura and others. More than 50 years have passed since then, and now it has become a reluctance change type (MR) head, and although the magnetic material has changed, the essence is the same, it is a position detection system that is resistant to adverse environments due to the magnetic detection method. Although it is inherent in machine tools, it is not easily affected by condensation and oil, and continues to have high vibration resistance and impact resistance. It also follows the thermal expansion and contraction of machine tool tables. The evolution of the Magnescale is the smart scale released in 2015. This system uses a tunnel magnetoresistive (TMR) element for the magnetic sensor, and the scale and head are completely separated by developing new magnetic materials, signal processing circuits, and insertion algorithms. With complete separation, the head and scale can be completely protected, and wear parts such as bearings can be eliminated. For NC machine tools, it has both the industry’s first IP67 environmental resistance and high resolution of 5 nm.

Features of Magnescale

MR sensor

Uses a scale with high-precision magnetic recording on a special magnetic material developed in-house. In addition, an MR sensor (magneto resistive sensor) with a unique detection pattern eliminates harmonic distortion components to achieve a highly accurate scale that is resistant to adverse environments and temperature changes.

Condensation and oil resistance

Since the Magnescale uses a magnetic detection method, it is not easily affected by dew condensation and oil that are unavoidable on machine tools, and stable and high accuracy can be obtained even in harsh environments.

Absolute Magnescale | Detection Principle

A 2-track pattern is recorded on the scale. The incremental track is engraved with signals of evenly spaced SN pitch, and the other is engraved with an address called M-code to realize absolute (absolute position). A special MR element developed for scale is used for magnetism detection, and high sensitivity and low distortion are realized.

Achieves high resolution with the interpolation processing technology of Magnescale

Interpolation processing technology is a technology that accurately divides the signal waveform detected from the magnetic scale into the required pitch (fineness). For example, the smart scale detects two sine waves that are 90 degrees out of phase with a magnetic scale engraved at a pitch of 400 μm. This is divided electrically, but if the signal contains distortion, accurate position information (true value) cannot be obtained. The DC component is removed from the signal detected from the scale, level adjustment and phase adjustment are performed in real time, and 80,000 divisions are performed by advanced processing to obtain position information with a resolution of 5 nm.