ZFB Belt Tensioner and Surge Unit

prusaprinters

<p>video of operation&nbsp;</p><figure class="media"><oembed url="https://youtu.be/xuXMjGIBOzs"></oembed></figure><p><br>&nbsp;</p><p>Warning - this is not 100% tidied up in the file, I will attempt to put aside some time to tidy up the assembly and make sure all components are present and named soon.</p><p>Use of this system is not without risk - servos are extremely powerful and this one is even more so with the gear reduction - use with caution! I have tried to design it as inherently safe as possible due to steel bars preventing over travel, but ultimately you use this device at your own risk. Have an emergency stop built into your rig and within reach of your fully seated position.</p><p>If anyone likes to attempt this project, it would be great if you could take photos along the way and maybe make any observations to assist with making a guide - it avoids me having to disassemble my own!</p><p>A couple of notes - access to a lathe will greatly assist in the construction. The steel rods need to be centre drilled and threaded but this can be achieved with a pillar drill or a hand drill and a drill guide if needed... or buy an appropriately sized hollow rod to allow tapping. The hex rods do have end machining to mate with bearings but you could alter the design quite easily if this causes a problem for you - just use the hex spacer methodology used elsewhere in the design and larger end bearings… if there is enough demand I may look to incporate a design with this option.</p><p>Materials wise I mostly used 3d jake tough PLA which seems to have held up fine. Most important to note is that the HTD pulleys need to be a very hard material (CF PLA or similar would be ideal) to prevent the sheer torque from rounding out the internal hexes slightly which can introduce slop. This could be mitigated in a future design by the use of a larger hex rod but it pushes further cost increases with larger bearings and larger hex bar so as yet undecided - with the appropriate material the current design has served well.</p><p>The plantary sun gear is a critical part and absolutely must be made of a material that has high layer to layer adhesion - ensure your material choice, temperatures and print speed are all geared up for maximal layer strength. Again, not had a failure here myself but it's certainly the point that has the highest chance of failure in the system.</p><p>If you have any feedback for me, feel free to reach out. Without yet having instructions or a guide this project, whilst very achievable given the fusion assembly to guide you, is a fairly complex project and requires an accurately calibrated printer and an adventurous mind! Tolerances are tight by design to avoid slop and may require a little finessing with sandpaper etc at points.</p><p>Please do let me know if you want to take this on and I'll help where I can.</p><p>I do have a belt roller unit as well which I will add into the file when I get a chance.</p><p>Cheers!</p>