Bearings company NSK has achieved a 40 per cent reduction in production costs for a major manufacturer of automated welding guns by replacing the manufacturer’s existing actuation mechanism, using planetary roller screws, with high-quality, silent running NSK ballscrews that offer maximised efficiency and load carrying as a result of integrating a greater number of load carrying balls.
NSK was called in as part of a cost reduction strategy introduced by the welding gun manufacturer, and tasked with providing a lower cost alternative to the planetary roller screws currently used. However, the alternative had to meet stringent operating demands: it must not reduce performance, nor increase energy consumption or levels of maintenance.
In the actual mechanics of providing an alternative, NSK had to take into account the fact that, in welding guns an extremely high load is applied in a very short time and always in the same point of the stroke. Therefore, to ensure reliable operation requires the maximum number of load carrying balls at equal load distribution.
Reduced friction and temperature
So NS proposed a SFD3605-12 unit that offered the key benefits of conforming to the same dimensions as the existing design, plus reductions in operating friction and temperature, as a result of changing from rollers to balls. These benefits have been achieved with a ballscrew that shows a 40 per cent cost saving, greatly improving competitiveness for the welding equipment manufacturer.
Key to the all-round improved performance of the NSK ballscrew is a new ball recirculation technique. This employs a deflector at each end of the ballnut to ensure that the load carrying balls are picked up tangentially, thus eliminating the direct ball-to-ball contact that causes noise and vibration. In addition, the improved design also provides smoother and more stable running at low speeds, important qualities in ensuring high reliability and accuracy in machine tool and other precision equipment applications.
NSK’s precision ballscrews are included in a new pocket-sized guide detailing its range of linear motion equipment, encompassing everything from linear guides to Megatorque motors for precision direct drive applications. Free copies of the guide are available from NSK’s Freephone service on 0500 2327464.
