Festo unveils entirely new class of products – high performance linear motor based actuators

According to Festo’s Drives Manager, Nigel Dawson, “Festo’s entry in the linear motor based actuator market will hopefully cause people to re-evaluate their opinions about this type of technology. Until now, the use of linear motors for highly dynamic positioning applications, especially those requiring accurate repeatability, has proved something of a black art. We intend to change this, so that system designers eventually come to regard our linear motors as just another actuation technology choice. To bring this about, we effectively had to reinvent the linear motor, to come up with a tubular design that can be integrated in actuators with the same form factors as our pneumatic products.”

Festo’s new ELGL-LAS linear motor axis employs a magnetically preloaded air cushion bearing to ensure very precise positioning and excellent linearity. The motor is a conventional linear synchronous design; the stator takes the form of a fixed bed, and the windings in the moving carriage are fed with drive signals from the motor controller. The carriage features an integrated displacement transducer to provide digital position feedback to the controller, and up to three carriages can be used on the same bed and controlled independently. The carriage also contains a series of embedded permanent magnets to provide an integrated locking brake function – the carriage is only free to move when the air cushion overcomes the magnets’ attraction to the fixed bed. Furthermore, the use of an air cushion bearing minimises friction in the guide components, making lubrication and routine maintenance unnecessary.

At launch, there is a choice of six ELGL-LAS linear motor axes; one model has a standard stroke length of 1 metre, while the other five models provide 2 metre stroke lengths and offer a variety of different acceleration, speed and thrust ratings. The most powerful 2-metre axis can handle acceleration rates of up to 50 metres/second/second and speeds as high as 4 metres/second, and can produce a continuous force of 349 N, with a peak rating of 463 N. All six models have a very high repetition accuracy of ±0.01 mm. The 2-metre models are available ex-stock; Festo will also produce models with stroke lengths up to 6 metres, to special order.

ELGL-LAS linear motor axes are ideal for applications that demand high positioning accuracy and stiffness. Typically, these include electronics assembly, semiconductor manufacturing, medical scanning systems and small parts handling systems. The axes’ air cushion bearings also make them relatively impervious to dirt, allowing them to be used as transport mechanisms in dusty environments, such as the wood-working industry.

Festo’s ELGL-LAS linear motor axes have similar form factors to the company’s pneumatic linear actuators, making it very easy for system designers to mix and match different drive technologies to create task-optimised automation. The company produces a wide range of accessories for the ELGL-LAS axes – including controllers, limit switches, mounting brackets, cables and energy chain holders – to further simply this task.