extruder reducté 3:1 bowden pour disco-easy

thingiverse

Here is the rewritten text in American English, without foreign characters and following all other rules. Hey guys, I've got a little reducer for your extruder to make those pesky filaments stop clacking or if you want to reduce the diameter of your nozzle. This has been in service for 2 months now and I haven't had any problems. No visible wear despite passing a dozen kilos of PLA. You'll need to retrieve the original extruder arm from your discoeasy, as well as the filament guide, spring, and gear train for assembly (don't forget the Nema 17...). You'll also need: - A 5mm bolt - Three 685zz bearings - One 5mm washer - Several 5mm screws - And four frustum head wood screws with a diameter of 3.5mm The assembly is simple: - Mount the Nema on the support, integrating the foot of the entire thing. - Pass the 5mm bolt through two 685zz bearings and then into the extruder's support. - Place two screws to hold the bolt head against the bearings and tighten them. - Place a 60-tooth wheel in the last screw you just tightened and block it with another screw (yeah...). Now, things get tricky: - Mount the cap. - From there on out, everything goes through the extruder arm's slot. - Mount the last bearing and place it in its designated spot on the cap. - Place a 5mm washer. - Mount the extrusion gear (the copper wheel... sorry for my lack of technical vocabulary!). I tapped mine so I wouldn't have to force it during assembly. - Mount a screw (for this one, I used a nylstop). - Tighten everything up (don't forget the last bearing's screw). - Remount the arm with your extruder's spring. Normally, you should be left with two 3mm screws from your old extruder on the table. I'll explain how to use them in a future project that's still in testing: a larger format core XY printer that's way more advanced than this setup you've just assembled. But wait, there's more: - Now you need to parameterize your firmware (in my case, Marlin RC8) by modifying the extruder motor step rate. - First, invert the Nema's rotation direction (and yes, we put an gear in!). To do this, find the line in configuration.h: ``` #define INVERT_E0_DIR false ``` And replace "false" with "true". - Next, find the next line in configuration.h: ``` #define DEFAULT_AXIS_STEPS_PER_UNIT { 80, 80, 1600, 98 } ``` My 1600 is set because I have trapezoidal screws on Z, so it's possible you'll have a value close to 2500 if you're still using the original configuration with 1.25mm threads. - You'll need to modify the value (98) to 285, which corresponds to the motor step rate. This value can be adjusted during calibration. Here's how: o Remove your bowden tube from the extruder. o Cut the filament at the nozzle exit. o Extrude 100mm of filament using your printer. o Measure the filament with a caliper. o Adjust the firmware value using a ruler. o Repeat until satisfied. And that's it! In practice, you'll need to widen the foot because the Nema's weight can cause the entire assembly to tip over (without gravity). Not done yet because I've mounted it on my new project's frame. You might want to consider adding an adjustable 60-tooth wheel to make tightening the Nema easier. I'm currently testing a different setup with beveled wheels that work perfectly, but I'll update this when it's confirmed.