b'Monitoring Microdrill WearHe compared a resistive shuntbreakage technologies are avail-and Breakage sensor with a Hall effect sensor,able, such as those that measure vi-which is a commonly used sensorbration, acoustic emission or ma-a machining center, ranging from afor estimating power consumptionchine tool displacement, but he said microdrill to a large-diameter end- by combining current informationhe has gravitated to power moni-mill, the motor must be sized for theand voltage tap information. A re- toring over the course of his career, endmill. sistive shunt sensor has accuracyespecially when monitoring micro-Thats how we developed thefor amplitude and phase measure- tools. He said the installation work technology in the first place, Cosicment of greater than 98% on non- occurs in a machines electrical cab-said, because we often find our- sinusoidal waveforms versus aboutinet and doesnt involve placing me-selves monitoring big and small80% for a Hall effect sensor andchanical, optical or any other sen-tools on the same machine. Auto- has a real-world response time ofsors in the machining envelope.motive is my typical application. 5 milliseconds versus 25 to 500 mil- Eachtechnologyhasits A conventional microdrilling op- liseconds for a Hall effect sensor,strengths and weaknesses, Cosic eration in the automotive industryhe said. In addition, the WattPilotesaid, and I have applied all these might require monitoring a 1.5 mmpower sensor has a sensitivity oftechnologies to machine tools in (0.059") drill on a machining center1 part in 65,000 (0.5-W resolutionthe last 30 years or so. My expe-with a 30-kW spindle. But he saidon a 32-kW spindle motor) versusrience indicates power is a good the companys system has moni- about 1 part in 6,000 (greater thantechnology. Its easy to install, ret-tored a 0.15 mm (0.006") drill rotated5-W resolution on a 32-kW spindlerofit and test. Thats why Im a fan by a 1.5-kW spindle for a medicalmotor) for a Hall effect sensor. of power.application. We can do things that perhapsFor more information about Dig-Thats far removed from whatmany people dont believe is possi- ital Way, visit www.digitalway.fr or you might see in the auto industry,ble, Cosic said. call 805-433-2820.CTECosic said. Other in-process tool wear and Alan Richter24JULY 2021SmallParts.indd 24 6/17/21 11:09 AM'