Actuator moves to electronics assembly

Edited by the Engineeringtalk editorial team Apr 28, 2003

THK has a miniature actuator designed for use in a wide range of electronics applications, including the production and handling of components, pick and place and clean-room manufacturing.

THK has a miniature actuator designed for use in a wide range of electronics applications, including the production and handling of components, pick and place and clean-room manufacturing.

Called the KR15, the new product consists of a combined miniature linear motion guide and miniature ball screw, creating a unit that is highly accurate and provides outstanding rigidity.

The KR15 features stainless steel outer rails on both sides of the inner block.

A ball screw runs through the middle of the block, to form a highly rigid one-piece structure that produces excellent levels of precision, enabling, for example, components such as integrated circuits to be moved and placed at high speed to within +/-0.003mm.

The design also includes two load-bearing ball tracks on either side, arranged so that the balls have an angular contact in relation to one another.

This allows the linear actuator to bear equal loads in all four directions, which means there are no restrictions regarding its mounting position.

In addition, the four raceways that carry the load are formed in a circular-arc grove, which allows the balls to roll easily even under a pre-load, eliminating clearances and minimising variations in frictional resistance; this results in extremely smooth and precise movement at a sub micron level.

Unlike traditional linear guides the KR15 has a U-shaped outer rail, reducing the overall weight of the actuator, while minimising any bending of the beam during operation.

This allows for it to be used in suspended "simply supported" formations as well as standard mountings.

The accuracy and small envelope of each actuator is enhanced as the ball screw runs longitudinally through the centre of the guides, which minimises the effect of pitching and yawning while optimising overall size.

The KR15 is available in a choice of lengths, with normal, high and precision accuracies available, and comes prepacked as standard with THK AFF clean-room grease to minimise particle emissions.