"Print-in-place" Roller Bearing

grabcad

Design Conception:When coming up with this design, I wanted to focus on the strengths of 3D printing and take advantage of them with my entry. The aspect that resonated with me is the “print-in-place” opportunities that 3D printing opens the door to. Being able to seamlessly construct enclosed geometries in one place (without any of the traditional manufacturing/processing) is a great opportunity to lower cost and complexity.Another key idea I embarked with was to create a design which is easily printable on ALL (entry level and above) 3D printers with standard 0.2mm layer heights (and 0.4mm nozzle), as I wanted to prove the capabilities of even cheap 3D printers and I want my design to be accessible to the entire 3D printing community.I started by researching different types of bearings. I avoided the traditional “ball” bearing as its spherical shaped components would prove difficult when printing on a small scale. The idea of a “roller” bearing seemed to be the perfect fit, allowing for good first layer contact with the print bed. I chose a 608 bearing as the standardised size for my design as it's very common. Using CAD software, dimensions could be easily changed to match other bearing sizes.Design choices:After much testing, the unique “peanut” shaped rollers proved to be the most effective. Their geometry allows for an easy print by maintaining sufficient cross-sectional area their entire height. They are also less prone to frictional losses due to reduced area of contacts with the rings. Additionally, the grooves placed on the outer and inner rings help to keep the “peanut” bearings on track and always held captive within the enclosure.Real bearings tend to have cages to create constant spacing between each roller/ball and prevent bunching. In my design, I adapted this idea to be 3D printable by adding small teeth on the outer ring which keeps each roller in its respective portion.Details:The attached STL file was created with FDM printing technology in mind but could be easily adapted to other methods. The model has been optimised to be quick to print (under 30 minutes). I used stress simulation to determine the force propagation of the bearing in an uneven loading scenario. As you can see, the stress is transferred from the outer ring and divided amongst the rollers. This helped me evaluate adequate thickness of the rollers and cages.The design depicted in the images has grooves on the outer and inner rings for extra grip, however these details are mostly aesthetic in nature and can be omitted. For this reason, I have also included the STL file for the simplified version. I’m confident that given time, the 3D printing community would be able to think of far more interesting and clever usages than the ones I showed in my video.Tips for printing:-If the bearing does not have full movement after printing, it is likely a bed leveling issue. You can still try gently break the rollers free.-BE CAREFUL when removing the bearing from the print bed, use a spatula to slide underneath. -Ensure the print bed is clean, as the first few layers are crucial in the smooth operation of the bearing.-Print the bearing so the side with the surface indents is flat to the bed. Alternatively, these surface indents can be removed entirely (see pictures for examples.)School/University: Monash University (Melbourne)