Heatbed cabling strain relief

thingiverse

Update August 28, 2017 I recently attached a rear-mounted cooler fan to the extruder assembly and discovered that the strain relief was obstructing the new fan assembly. So I redesigned the armatures to provide a lower profile and keep the assembly below the heat bed's height. Additionally, I tweaked the cable clamp so it interlocks perfectly, labeling all new parts as v4, with purple printed parts in the images displaying the new components. I have removed older files since these new ones supersede them. A common failure in Prusa i3s is the heatbed cable breaking over time, depending on the heatbed type, there are strain relief options available. The ones I found here all used a heatbed with 2.54mm standard jumper pins, so I created my own. This part might be overengineered, but I wanted to try using printed parts only and enjoy manufacturing everything myself. It takes advantage of the lower aluminum plate beneath the heat bed, clamping a plate assembly firmly into place. The plate assembly features three square openings for attachments; I'm currently using the central one, but built in three as it's possible to have other attachments, like an LED light or even a GoPro. I'll be looking into both of these soon and probably strengthen the plate and make the armatures that lock onto it stronger. I measured the gap between the lower plate and black frame on my Wanhao Duplicator i3 and found approximately 1.8mm to 2mm; the bottom half of the lower frame plate is 1.5mm thick, providing enough room for the Y-axis not to hit the outer frame when fully deflected in either direction, ensuring the Y-axis limit switch remains unaffected. Please check this dimension on your printer! The strain relief photos tell it all; I used cable ties to clamp the cable in place and designed a small split pin, but I was overoptimistic about its strength. All files are uploaded, including the split pin. I printed this at either 100 or 200 microns, with tight tolerances requiring some honing depending on your printer's tolerances; everything locks together very snugly, and the strain relief arms may appear flimsy but they're up to the task. Print the threaded parts at 100 microns for better results. I'll be tweaking the design a bit more but wanted to get this up now; here are some future tweak considerations: (1) Reduce the angle of the armatures coming from the lower plate, as they push the heatbed cable up a little too high. (2) The cable clamp assembly needs to be wider and will make it better suited for cable ties. Update: I have added 145-degree armatures to solve tweak (1) and widened the cable clamps and added cable tie guides (2) to the top and bottom cable clamp, labeling all three additional parts as 145 degrees. Print Settings: Printer Brand: RepRap Printer: Wanhao Duplicator i3 Rafts: No Supports: Yes Resolution: 100 microns Infill: 25% Notes: Only supports used on Plate locking arm with female M8 thread and the Lower frame plate