When performing circular interpolation, irregular friction can arise when a ballscrew reverses, resulting in a deviation from the intended path. These motion errors, known as quadrant glitches, leave micron-level imperfections that appear as undesirable streaks or protrusions in workpiece surfaces.
The usual way to address the issue is to apply software compensation in the servo controller. However, the frictional variations that occur when a ballscrew reverses direction are difficult to predict and software cannot provide full compensation, thus requiring improvements in ballscrew technology.
NSK says it is using proprietary friction control and high-precision evaluation and measurement technologies to reduce the frictional fluctuations that occur when ballscrews reverse their direction of motion.
By fitting the new-technology ballscrews to machine tools, it will be possible to achieve higher quality surface finishes when machining moulds, dies and precision components. NSK predicts that the technology will reduce the need for secondary polishing/burnishing processes and help to save energy.