I moved my extruder from my MPCNC to the MP3DP I built, and I am getting really bad stringing, which I wasn’t getting before on my MPCNC. I am using the same slicer settings as before. The things that are different are it is a different RAMPS board, and different drivers, and using the MP3DP firmware instead of the MPCNC firmware. I have messed around with the retraction distance and speed and it doesn’t seem to make any noticeable difference. I was wondering if perhaps the extruder driver needs to be increased a little bit and that it doesn’t have the power to retract? I’m not hearing any funny noises from the stepper motor though.
With the MPCNC my retraction distance was 1mm and 35mm/s retract speed. I am at 4mm now and 50mm/s with no improvement.
One more thing I forgot. I didn’t print a new fan mount, because I thought they were the same between MPCNC and MP3DP, but I think they are mirrored, so I flipped things around to get the fan to line up with the print head. I don’t think this is problematic, but who knows…
I think the stringing might actually be because of the fan. It appears to be blowing right on the thermistor which I think is overheating the filament. I will try to test tonight.
When I first put the E3D v6 clone on mine I didn’t check the temp sensor. It was pushed into the hole but had no thermal grease, so it read pretty erratically. Adding some thermal grease from the heat sink of an old broken laptop really smoothed things out. The PID for the hot end has almost no wiggle.
Now if I could just figure out retraction settings for a bowden setup, to clean up my stringing…
I’m printing a retraction test right now, but I am blown away with how nice my prints are coming out now. Hopefully the stringing is at an acceptable level. I got the new fan shroud printed. I think I am done other than maybe adding an inductive sensor. I have a lot of friends at work with 3D printers and most of them have spent a lot more time tuning their printers. This one just worked minus my bonehead mistakes.
