THK NR-X / NR Series Super-Heavy Load Radial Full-Ball LM Guide
The THK NR-X / NR Series is a full-ball LM Guide built for super-heavy loads. Its raceways are cut into deep grooves with a radius closer to the ball diameter than in conventional designs, using specialized equipment and precise cutting technique. This gives the series high rigidity, strong vibration and impact resistance, and improved damping capacity, all important qualities for machine tool applications.
While the guide isn’t cutting, it travels smoothly as normal. But when a cutting force is applied, the contact area between the balls and raceway increases, creating a mix of rolling and sliding motion. This raises friction resistance and improves damping, without adding wear or affecting service life, since the slip involved stays minimal.
Unlike a Gothic-arch groove design, the NR-X / NR Series avoids excessive differential slip. This lets it travel smoothly and reach high positioning accuracy even during fast feeding, making it a practical option for demanding cutting operations. Since raceway curvature is closely matched to the ball diameter, ball contact area increases under load, giving the series strong capacity to handle super-heavy loads.
There are 10 model variants, covering standard, long block, and ultra long block options, with flanged and non-flanged types, and various bolt mounting configurations. Sizes range from 25 to 100, with basic dynamic load ratings from 37.1 kN to 599 kN and basic static load ratings from 68.1 kN to 1,300 kN, depending on the model. Because of its extremely high rigidity, this series doesn’t easily absorb mounting surface misalignment or installation errors.
