So I have an Ender 3 Max and recently tried the SKR mini e3 v3 mainboard upgrade. The install went fine, and managed to compile the firmware with VSCode.
I used compatible Ender 3 Pro firmware for the SKR Mini v3 e3, then edited sizes and some other things in the config.h which were recommended on a GitHub page with custom FW for the Max.
So the issue I’m having is with under extrusion. I tried to calculate e-steps, and found per 100mm I’m only extruding about 32mm. I calculated and entered 290.5 as my e-steps mm, and it made absolutely NO difference. I’ve checked that I don’t have volumetric extrusion enabled (it isn’t) and now I’m stuck. Somethings clearly off with the e-steps, I’ll check my wiring again for now.
My nozzle is fine and my filament is pulling properly.
I would recommend checking the config files to make sure that the esteps are not possibly being specified in 2 locations or that the line is not accidentally commented out. In theory you should also be able to adjust the esteps from the printer control panel too.
I got frustrated and installed the older 4.2.2 board. It does seem to be working correctly, though I’m having issues seeing if the extrusion issue is from a bad cog (I’m using a RedRex dual gear extruder) and I’m noticing a small bit of slippage which I may have corrected.
Though it’s immediately better than the SKR mini was outputting so I think I’ll return this board for another, unless I am certain there’s a lot of slippage with the cog, I’d feel better knowing I’m getting a board with out a bad stepper.
Thanks for the vid! I actually bought some replacement brass tension gears, and that fixed any prior slippage I was having. Also, the problem had to do with my fan wiring, causing heat creep that melted the filament inside the Bowden tubing. I fixed the wiring…
Now back to installing the SKR mini e3. I figured out that there’s a misprint on the label for the fan positions, which was definitely why I was having problems with extrusion. With no cooling, heat was creeping and taking away about 75% of the filament extrusion. At least that hurdle is over, back to the e3 board install tonight.
Well the SKR is working better now, though I had to set the eSteps to 133, and boost my bed and nozzle temps. I need to do a PID tune really.
Going from a 4.2.2 Creality board to the SKR mini e3 poses the following problems:
The stock 4.2.2 joins the motherboard and parts cooling fan together, meaning that if you don’t redo this wiring, the SKR mini will only be cooled when parts are cooled.
Wiring the motherboard fan directy to the 24V input is one workaround.
The hotend fan/parts cooling fan and mainboard fan should be wired like the picture, on the box this is mislabelled, which was causing my heat creep.
Other than those issues (which aren’t mentioned much) the SKR is great.
