Shopping for Microstepping Technology

The affordability and reliability of step motors—“steppers”—has made this technology highly popular among machine builders in many industries, ranging from electronics to aircraft controls to CNC equipment.

One of the major reasons for this is the application of microstepping drives, which have improved the smoothness and accuracy of the step motors.

Yet, for some, microstepping technology still has some conspicuous drawbacks: namely, vibration, noise and harmonic resonance issues.

Matthew Dunne, president of Align-Rite Tool Company in Tuscon, Ariz., was looking for quiet operation and smooth movement. Align-Rite makes a range of CNC routers and mills, plus other tools used by fabricators in the woodworking, jewelry, metalworking and solid surface industries. He switched to a SoftStep drive system from Testra Corp. (www.testra.com, Tempe, Ariz.) because “you get really accurate, very quiet drives compared to other ones. The stepper motors were so quiet that I though the machine wasn’t running.”

Testra President Thomas Hart says the SoftStep technology “essentially converts driver data into ultra-fine microstepping (256 microsteps per motor step), ramping speeds up and down between steps to create a very smooth motion without the traditional stepper clicking, buzzing or whining noises. Through the SoftStep advancement to microstepping, a step motor drive is approaching the level of smooth performance of continuous rotation motors, while still being a lower price option.”

Dunne says “because the drives virtually eliminate the vibration, so you [also] get a much smoother movement on your X, Y and Z axes.” That means Align-Rite’s wood routers are capable of going faster with smaller bits, greater accuracy, and less a tendency to break bits.

“When you get down to some of our smaller bits—people doing the pool cue inlays and things like that—you have to have a CNC router that can run at a fairly high speed, but very smoothly. Our high-end cue builders need to have a seamless inlay on their cues,” Dunne says. “For applications such as jewelry, or where you have expensive Corian inlays, you must have a very smooth stepper system so that you don’t have any chipping from vibration.”     

Renee Robbins Bassett, rbassett@automationworld.com, is Managing Editor of Automation World.
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