Roller screws cost more than ball screws but the extra expenditure on products such as those in SKF's 'preferred range' is justified through their superior performance in a host of applications.
Many customers are willing to pay a premium for superior performance, as demonstrated by the fat that roller screws continue to be specified in a diversity of industrial applications.
Roller screws cost more than ball screws because they are manufactured to more precise tolerances and use greater numbers of precision components. This means that they offer many advantages:
- greater load-carrying capacity
- superior power density
- faster speed
- higher acceleration
- greater reliability
- higher positional accuracy
Phil Nicholas, Business Development Manager for Linear and Actuation Technology at SKF, says: "As a consequence, they can be used in more demanding applications. In many cases, the extra investment can be recovered later: the higher load-carrying capacity can lead to a tenfold increase in service life, for instance."
SKF offera a diversity of roller screws but, in order to provide greater value – and shorter lead times – it offers a 'preferred range' of the most frequently used sizes of planetary roller screws and recirculating roller screws, along with standard-sized nuts. Shafts are manufactured according to customer requirements.
Typical machinery that benefits from the inherent advantages of roller screws includes plastic injection moulding machines, industrial spray guns and medical devices.
In injection moulding machinery, SKF's Ultra Power roller screws are used in the injection and clamping mechanism of models that exert a clamping pressure of up to 200 tonnes. At the same time, they boost energy efficiency and improve cleanliness by banishing hydraulic oil.
Roller screws are also used in factory automation systems – for operations such as gluing, riveting and welding – thanks to their accuracy and repeatability, faster resetting, reduced downtime and compactness. In microchip encapsulation, the reduced footprint, increased duty cycle and longer lifetime, along with reduced maintenance, are the main reasons for using them.
Away from engineering production, they are even used in the electromechanical drive of radiotherapy couches, which must be positioned accurately before gamma rays are directed into the patient.
On top of this, there are many examples in the marine, offshore, pulp and paper, and aerospace industries.
Follow the link for more information about SKF's roller screws.