LM08UU linear bearing

prusaprinters

<h3>LM08UU linear bearing (linear and tapered)</h3><p>This is my proposal of linear bearings of LM08UU type.</p><p>There is two types, a linear and a tapered one. Both are drill types which means you need a 8mm drill to adjust the inner diameter.</p><h3>Drill Type</h3><p>Sliding bearings have less weight and are more silent than ball bearings. Additionally they do not need oil. But printed bearings normally do not reach the necessary precision. Even if they may fit perfectly by accident, there typically is not a complete contact on the whole inner surface but only on some smaller regions. This may work quite good at the beginning, but there often is a quite fast increase of tolerances by abrasion of these small regions.<br>I tried to overcome this problem by designing a more flexible structure. But then the printer bed tends to oscillate and thus gets less precise, again.<br>For this reason I decided to go for drilled bearings which from my point of view are the best choice to achieve precision and endurance.<br>Drilled bearing means that you should enlarge the inner hole by an 8mm drill carefully until it fits on your rail.</p><h3>Tapered</h3><p>Bearings should typically be mounted with some force. Otherwise they may move within the mounting block generating some unwanted noise.<br>Unfortunately, non-metal bearings often are very sensitive against pressure (Even original IGUS do this as well). If you apply some force from outside, it usually will create more friction on the inner side towards the rail.<br>For this reason I designed a tapered type bearing:</p><ul><li>One half of the bearing has a smaller inner and outer diameter, the half a lager one.</li><li>Fixing of the bearing will be done at the larger diameter part. If some compression occurs, it can be compensated by the larger inner radius.</li><li>If you have 2 bearings on one rail, the length of the bearing does not matter anymore. The distance of the 2 bearings mainly is defining the effective length.<br>For the tapered type a special bearing block is available (https://www.thingiverse.com/thing:3524668).</li></ul><h3>&nbsp;</h3><h3>History</h3><h4>Version 0.3.0</h4><p>First published version and currently in use.</p><h3>&nbsp;</h3><h3>Print instructions</h3><p><strong>Rafts: </strong>Recommended if heat bed adhesion is an issue</p><p><strong>Supports: </strong>No</p><p><strong>Resolution: </strong>0.2mm</p><p><strong>Infill: </strong>100%</p><p><strong>Filament:</strong> Doesn't matter</p><p>&nbsp;</p><p>&nbsp;</p>