Low-profile linear axis offer good dynamics

Paul Boughton

With its new series MLD-FU direct-drive flat linear axes, Schunk is launching a family of actuators that is suitable for applications with high dynamic requirements and small to medium loads.

 A three-phase, electronically commuted ac synchronous linear motor is used as the drive. The energised primary part is integrated in the slide; the secondary part, with its high-quality permanent magnets, is in the base body. The direct drive architecture enables the moving mass to be reduced and the modules to be made very slim.

The base body of the linear axis consists of an aluminium press-drawn section onto which is built a highly dynamic resilient rail system with roller guides. The guided slide, into which the primary part and measuring head are directly integrated, moves on it completely free from play due to preloaded needle roller bearing units. The MLD-FU is available in lengths up to 4000mm, driving forces up to 600Nm and with a repeat accuracy of +/- 0.01mm.

Due to its excellent price-performance ratio, the MLD-FU series is especially suitable for cost-conscious applications and can be adapted with numerous options to more special requirements as well. For example, if axial forces are applied in the target position, stress on the linear motor can be reduced by means of a pneumatic brake.

Another advantage is that multiple independent motor slides can operate on a single guide profile, which is useful for handling units with overlapping operating ranges. With a second, passive guided slide that is freely movable, long attachments can also be realised.

A wide range of accessories is available; for example, control units from Bosch-Rexroth and Siemens are available. Limit switching and referencing can be achieved via inductive sensors; alternatively a new magnetic absolute position measuring system is available, enabling time-consuming reference runs to be eliminated and limit switches to be dispensed with. Hydraulic shock absorbers on the profile end plates absorb shock loads, and prefabricated cable tracks mounted directly on the drive are available for energy transmission. As well as adapter plates for standard and special configurations, ready-made cable sets in various lengths are also available. Optional stainless steel guides expand the range of application of the MLD-FU with respect to applications at risk from corrosion.

For more information, visit www.schunk.com

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