Of all the factors that contribute to the premature failure of linear bearings, misalignment ranks near the top of the list. Here’s how to cope without breaking the bank.
When design engineers evaluate linear bearings, they always ask about performance attributes such as speed, load capacity and lifecycle. Then they want to know the price. It’s rare, however, that they ask about the bearing’s sensitivity to misalignment. And that’s a big mistake, because misalignment represents one of the leading causes of premature linear bearing wear and failure.
Linear bearings that should last for years based on expected life calculations can quit after a just few months if they are not aligned to the geometric tolerances they require to run smoothly. Usually, alignment problems begin with the design and preparation of the machine frame itself. It may not be flat, straight or parallel enough for a bearing to mounted properly. For example, mounting surfaces may have one or more high spots that will read through to the installed bearing rails. Or the frame design may make it difficult to mount bearing rails parallel to one another in the horizontal axis, vertical axis or both.