Entry zone in linear guide carriages

2024-06-27

There’s a thing called the entry zone in a linear guide carriage. This is where balls come out of the return channel and re-enter the load zone – where they actually carry the load.

At speeds like 3 m/s, about 1.5 meters worth of balls enter the load zone per second (balls move at about half the carriage speed).

What’s the critical part here?

In most carriages, the ball raceway and body are ground in one piece – which makes it super difficult to create a perfectly smooth entry. There’s often a “step” the ball has to get over. So the ball kind of “waits” at the entrance until the one behind forces it in – creating a mechanical impact and friction spike every time.

But some guides have a spring-loaded entry zone – meaning the balls are gently guided in with no step, no hit, just a smooth transition. The preload and force build up gradually.

So what’s the upside?

Movement becomes much smoother – which can improve your product quality. And since the balls contribute to load capacity even in the entry zone, the overall load rating improves too – sometimes doubling the lifespan compared to traditional designs.

Watch Carry Lindholm explain this in a detailed video.