MMU works great, but wipe tower creates nozzle blobs
I've been having very good luck with my MMU. It doesn't screw up very often. But the issue I have on every single print is that my wipe tower leaves huge blobs of filament on the nozzle. It seems that every 2 or 3 color changes I have to pause the print to grab the blob off of the nozzle with a pair of tweezers. Watching the wipe tower build I've found that the issue is when the nozzle travels back and forth without any filament in it. There are tiny strands that tend to form, and the back and forth over them just collect on the nozzle and eventually grow to be pretty large. If I leave the blob it eventually deposits on the print and causes a few screwed up layers where there is too much plastic for the nozzle to fit, and it "skips" that part as it moves over.
Re: MMU works great, but wipe tower creates nozzle blobs
I've been having very good luck with my MMU. It doesn't screw up very often. But the issue I have on every single print is that my wipe tower leaves huge blobs of filament on the nozzle. It seems that every 2 or 3 color changes I have to pause the print to grab the blob off of the nozzle with a pair of tweezers. Watching the wipe tower build I've found that the issue is when the nozzle travels back and forth without any filament in it. There are tiny strands that tend to form, and the back and forth over them just collect on the nozzle and eventually grow to be pretty large. If I leave the blob it eventually deposits on the print and causes a few screwed up layers where there is too much plastic for the nozzle to fit, and it "skips" that part as it moves over.
One thing to try is reducing the "maximum bridge distance" on the wipe tower parameters. That will give the wipe tower more structure to hold the plastic in place.
I recently had a problem with some very gooey PETG which was doing something similar, and this helped a lot. I set the maximum bridge distance to 3mm.
Re: MMU works great, but wipe tower creates nozzle blobs
Interestingly enough, this happens when the wipe tower is still solid. I was reading through the 1.0.3 firmware thread and read that other people are having issues with PETG wipe towers because it prints so fast. I found that with the latest printer firmware and printing via Octoprint I can pause the print and resume and the wipe tower will go super slow. I have to pause after every filament change, but I'm doing that anyway to clean off the nozzle. When it wipes at 10(?)mm/s the nozzle stays nice and clean. So maybe a future firmware update will allow us to slow down the wipe tower and keep this from happening.
Re: MMU works great, but wipe tower creates nozzle blobs
noob question. Is the wipe tower set by the slicer, or by the printer?
Re: MMU works great, but wipe tower creates nozzle blobs
noob question. Is the wipe tower set by the slicer, or by the printer?
The slicer.