Our customer was producing air core gauges using an older process using ceramic magnets. The magnet was zinc die cast onto a small, precision shaft. This presented several problems. The ceramic magnets often cracked and require precision grinding to fit into the cavity of the die cast machine to be assembled, which was expensive. Even worse, the zinc die cast machines had to be hand loaded and were dangerous to the operator. The assembly also required a precise shaft with extremely tight tolerance that had supply chain issues that may sourcing difficult.

EAM was able to eliminate the three-part assembly and injection mold the magnet right to the shaft.

The plastic bonded magnets were more robust and didn’t crack. Because of the molding process EAM was able to make two different magnetic grades off the same tool, which the customer utilized for two different gauges increasing their overall production yield. These magnets are used for gauges in heavy construction equipment.  Lastly, EAM was able to successfully source the shaft locally eliminating supply chain issues.

EA Magnetics supplies all industries and we are IATF 16949 certified! Contact us today, we look forward to speaking with you!


About Air Core Gauges:

An air core gauge is a specific type of rotary actuator in an analog display gauge that allows an indicator to rotate a full 360 degrees. It is used in gauges and displays, most commonly automotive instrument clusters.

An auto tachometer has a sweep of about 240-250 degrees and typically uses an air core gauge.

A typical automotive application is shown at the right. The air core gauge is a type of “air-core motor”. It may be considered a “gauge movement” or “pointer indication device”.