The blue one was printed using the defaults from Cura at 50mm/s. The green one at 30mm/s with no difference in the “ghosting”. Yes, there are other issues with the prints, but I’m working on the worst one (the “ghosting”) first.
Slowing down the print made no difference at all. Today I will try turning it 90 degrees on the platform.
What suggestions are there for reducing or eliminating this problem? Is it worth turning it 45 degrees instead of a full 90? Temperature changes shouldn’t make a difference (should it)?
Settings:
Extruder: 205
Bed: 60
Speed: 50 mm/s or 30 mm/s
Filament: eSun PLA
In case you’re wondering… I tried a couple of different models using Slic3r and, even though I copied settings from Cura, they were disasters. I have a Marvin with his feet welded together and watched as the extruder ran into the model and pushed the unfinished piece around the table. I heard the “snap” as it broke loose (it didn’t just release on its own).
I had this problem with ABS on almost everything I printed, it still happens now but not bad enough for me to worry about. I simply turned the temp down from 240 to 230, everything else I tried didn’t make any difference.
This looks to me like either an acceleration issue, a loose belt, or something similar. What printer is this, and do you know the acceleration setting?
As 3dprintdaddy said, this is usually an acceleration or even “jerk” issue. Acceleration is how fast the speed changes, jerk is how fast the acceleration changes. The ghosting shows up from the machine oscillating after it makes a sharp corner: from the letter detail, back to the flat background path. Turning down the speed doesn’t help because acceleration and jerk limits are usually set in firmware and are not based on speed. I saw this on the lulzbot tag so I assume you have one of their machines. In that case, you can change acceleration limits by navigating the on-screen menu. Just be sure to write down the original settings, and then save the settings after you change them. Try cutting the acceleration value in half or even down to 30% of original. That should make a noticeable change in the way it prints (and it will take longer). It may not eliminate ghosting, but if it changes the duration of the echos or their spacing, then you are on the right track.
I guess I forgot to mention that it is a new Taz 5. I will look into the acceleration issue. It’s not a complete show-stopper, but it definitely impacts the aesthetics.
Printing one turned 90 degrees right now to see if it makes a difference. I will change the acceleration and try again after this one is done.
I see this with my Taz 5 but haven’t done much to work on it (also a new machine). In other machines, acceleration limits have helped with it. The Taz 5 is a great machine but the hotend carriage does have a bit of play (grab the nozzle and you can get it to wiggle a bit).
Okay, I got the chance to look at the settings and the acceleration is at its lowest level already. I can turn it up, but not down. Sounds like I don’t really want to turn it up.
I see two settings for “jerk” and I will do a lot more research on those before I start playing with them. There is nothing in the manual about those settings (except that most people should never play with them).
I build printers from bare metal and I have a lot of experience in alleviating this problem. FIRST AND FOREMOST check your belts. They should be TIGHT. Then check everything else. Yes, it can be machine and wobble but if your machine is not stable we shouldn’t be this far into the conversation. If you can see your machine moving then secure that first. Anything obvious, should be addressed and tested. Troubleshooting has a method. If too many things are tried at once you will have no idea what the fix was. Go through the entire machine and make sure everything is tight. Then try to print. 99.9% of the time it is loose belts. The extra slop/play in the belt causes the extruder carriage to play “catch up” as the slack is brought in on change of direction. Once you are certain the printers MECHANICS are sound then you turn to software calibration speed (accelleration/jerk and slicer settings). It makes sense when you ask the question, “How can you software tune an improperly function printer?” Hope this help clarify things.
