Did you know that you can build linear and circular displacement mechanisms with a piece of PTFE tubing known as Teflon and PETG filament? In this video I'm going to show you three functional mechanisms that move smoothly, support real loads, and are made with 3D printing. These are not industrial parts, nor are they intended to be. If you need precision, high rigidity, or heavy-duty use, commercial solutions are still better, such as these plastic bearings, linear bearings, rail slides, and large-diameter ball bearings. But when you're prototyping, testing ideas, or building low-load mechanisms, this combination of PTFE and PETG can work surprisingly well for just a few cents. At this point, you'll probably have a question. On AliExpress I can get almost everything at a low price with reasonable quality. Why would I use this method? The main advantage is that you don't need to buy special parts or wait weeks. PTFE tubing and PET G are easy to obtain. Very little material is used and the design can be adapted to almost any geometry. This is especially useful if you can't easily get the pieces in your country or when the project budget is really low. The first method does not require PETG, as it works on smooth steel rods or other rigid material and consists of printing grooved bearings where small segments of PTFE tubing are inserted inside according to the diameter of the rod. Although the coefficient of friction with steel is slightly higher, this method allows for printing more complex geometries, like this entire piece. Using this method, I have built this linear motion mechanism with two 8mm smooth rods and a NEMA 17 stepper motor. The sliding carriage is quite rigid, despite being short, and with a little lubricant on the rods, thousands of cycles can be achieved with very little wear. As a quick test, I wanted to use the mechanism to slide a mirrorless camera, so I attached a quarter-thread adapter to screw on a ball head. This particular is relatively large, which added to the camera results in a total mass of almost 1 kg and a height of 19 cm. The resulting movement is quite smooth and without visible oscillations, so it could be an interesting project to develop in depth. The following method consists of creating sliding mechanisms with a linear guide of PET Guston of the typical MGN. The skate is basically a solid block with a PTFE tube on each side that is inserted with light pressure into the guide. Using this method I have built this compact mechanism which I have previously used to analyze some inertial sensors and to create some shots with an action camera. Like the previous mechanism, the sliding block is quite solid and moves smoothly, but without needing steel rods. The last method allows creating large diameter circular bearings in a very simple way. The two circular tracks are printed on PET G and between them there is a channel where the PTFE tube is housed. By joining both pieces, a smooth movement and stable music are achieved. Using this method I have built this small platform that I have been using to rotate some objects and perform photogrammetry tests. These bearings work very well, as they are able to withstand considerable radial and axial loads , despite being made with only a few grams of plastic, but that doesn't mean it's a precision bearing or that it's intended for high loads. As a practical test, this platform can support a 5 kg dumbbell and continue to rotate smoothly despite using a small 10 N per cm stepper motor. In my next videos I will show you in more detail each of these mechanisms in case you are interested in building one of them, how the pieces are printed and what things to keep in mind to ensure smooth and stable movement. If you found this video helpful, please give it a like as it encourages me to continue sharing more content.