Identifying Applications for Ultrasonic-Assisted Machining

One emerging technology that is receiving notable attention is ultrasonic-assisted machining, or—more strictly speaking—rotary ultrasonic vibration-assisted machining, sometimes referred to by a simple acronym, UAM. Wikipedia has published the acronym RUM in its explanation of the process. Time will tell which one wins.

Certainly the technology is a winner as evidenced by impressive, practical results. Essentially the equipment is a hybrid of a three- to five-axis VMC combined with high-speed spindle rotation and high frequency vertical vibration of a diamond abrasive cutting tool. Unlike older ultrasonic machines (USM) that create an abrasive liquid slurry that covers the tool tip and workpiece and microchips material, UAM uses a cutting tool coated with polycrystalline diamonds that grind down the surface of the part. The rotational speeds on the UAM-assisted technology we represent from Tongtai are up to 24,000 rpm. The vibration frequency is in the 15–45 kHz range, and the amplitude span is 1–10 μm. Essentially this approach impacts the material with higher contact speed and thereby reduces the cutting forces. Forces are reduced as much as 30–300% depending on the material. As such, most of the benefits surround surface finish and integrity—finishes with an Ra of less than 0.2μm are possible and there’s a great reduction in surface and subsurface damage, such as microcracks and chipping. Naturally with less force, tools last longer, too.