Printer going off into random movements

[staticbunny]

For some reason when i extend out to almost 200mm on my print bed my printer loses control and then either ends up an inch or two off the print bed or ends up rubbing hard against the glass. It seems to happen when Z is extended out far. I don't feel like I'm really pushing it to far. Am i just printing too fast going at 100% for that distance? I can upload the file it happened on if someone wants to see. I can also attempt to record it to show whats happening as well.

I'm printing from the SD card and if i pause the print it doesn't home correctly and sounds really bad. but if i do home it it fixes it and im able to continue printing till it does that agin.

[mvansomeren]

Sounds like it may be mechanical. If this was happening to me, I would check:

1. The belts, make sure they aren't loose and skipping over the stepper motor gear
2. Make sure all of the joints in the Cheapskates, arms and effector plate have free movement and aren't binding.

[geneb]

Er... Yeah, that's not gonna work.

The MAX travel from the center point is around 130-140mm.

g.

[mvansomeren]

Er... Yeah, that's not gonna work.

The MAX travel from the center point is around 130-140mm.

g.

I just assumed that the OP was exaggerating the distance a bit since there is only 155mm from center to the edge of the bed. I was thinking that he just meant to the edge of the work area which is about 140mm max if everything is working perfectly.

[nitewatchman]

I sometimes have the same issue when printing at extremes. The effector will seem to pause or slow and then get as lost as a ball in high weeds.

I am confident that the processor is being overwhelmed and likey has had a data overflow and just dumped a bucket load of step. I have found that if I slow down the federate to 30mm/sec to 40mm/sec the problem goes away and the print can finish.

I ran into first printing the Akemake Spiral Speakers.

Also printing at 200mm may be a little wishful, I think my arms go flat before it reaches that radius.

[staticbunny]

Maybe I'm wrong about it being 200mm because the arm isn't going flat yet but it's getting somewhat close. It's around the warning text if i had to give a general location. My machine has no problem doing a 200mm circle text though, but that motion is a radius instead of a more intense motion like a fill layer. Let me try slowing down the feed and speed and see if that does anything. That will give me a chance to film or at least get a picture showing how big.

[Polygonhell]

One of the issues printing near the edge is all the firmware settings for speed/accelleration are set for platform motion, not carriage motion, so at the edges, you are effectively doubling them all or worse.
If dropping the speed doesn't fix it, drop the accelleration setting in the EEPROM as well.

[staticbunny]

It would be cool if the firmware knew to slowdown as you start getting out passed 150mm. I never should have said my printer was boring. It prints whatever i throw at it and it never has issues. Guess i hadn't really been using it right. :-p

It's all a learning experience. I'm trying to print a quadrocopter frame in carbon fiber. It kind of sucks that I'm having problems printing these large things but i'll get it figured out somehow.

Thanks to everyone who responded. I'll give an update with what I find out in case other people run into this issue.

[staticbunny]

So i realize now when i said 200mm i was measuring from the other side of the build not the center. So i would be more like 125mm out which isnt very far. I did find the unknown z issue post which was really interesting. The same place people were having issues based on the ABC XYC locations is the same place my printer started to wig out and randomly change Z height. I just installed my new CF arms and e3D hot end after my printer being down for a week. So once i'm back up and running I'll try the suggestions people posted here and if not I'll contact seemecnc support.