With the new series SPR / SPS THK provides a caged ball LM Guide that have the highest rigidity and the lowest waving among the THK linear motion guides with caged balls. Design features are 8-row raceway grooves, a smaller ball diameter and the longer overall LM block length.
The number of loaded balls varies when the balls are entering and leaving the loaded area. This causes a very small displacement of the block called "waving". In case of SPR/SPS the larger numbers of small balls can absorb the displacement up to 10% of the conventional linear guide- way (in the lower double-digit nanometer range) and therefore they are comparable to the hydrostatic guide system.
Additionally, SPR / SPS are characterized by extremely high rigidity, which is higher than that of the roller guide of comparable size (0.4µm/kN for SPS25LR with C0 preload).
Thus SPR / SPS are ideally suited for further accuracy optimization of high-precision machines, for example, grinding machines, multi-surface milling machines, jig borers and machines for production and inspection of semiconductors.
The SPR / SPS series is available in the common sizes 15, 20, 25, 30, 35 and 45 with some difference to the standard dimensions. Available are the radial type SPR and four way equal loading type SPS.