Layers out of alignment???

[jereywolf]

I am running this print which I have run before and it worked well. For some reason the layers are off this time. They aren't lining up with each other towards the top. I had this happen on a completely different print before too. Any ideas?

[jimc]

i have printed tall items before and gotten the same thing. i attributed it to the abs warping as it gets further from the bed plus curling from the bed combined with the bed shaking back and forth. these tall thin items can be tough. they get very little bed contact and are affected big time from drafts. i really have no proof but that is the assumption i came up with since really nothing else that i could think of could cause it.

[jereywolf]

That makes sense. The only difference between these ones and all of the other one that I ran was the infill. I was running these at 20%, while all of my other ones were at 35%. So the lower rigidity, may have made it more likely to move back and forth. There is no visible warping on these parts.

[Dale Reed]

You'll note that the bed is not super rigid. You can flex the spider a fair amount just by hand. The Y accelerations can leave the bed bouncing quite a bit, especially with the rapids between the two "towers". As the bed descends, the bounces result in error in X and Y gets "amplified" as you go higher on the part. A little bed flex at the bottom results in a small movement in X or Y at low layers, but a big shift at the top of the part. That's what it looks like to me in your photo...

From another topic on the forum, I got this (thanks Jin!), which might be worth trying:

Reduce X/Y acceleration down to 1000 or 800 to reduce ghosting.
Search for "M201" in the M2 tips thread: viewtopic.php?f=3&t=12

This was to reduce the "ringing" at corners. To reduce the bed shaking that is moving the tops of the part, you may want to reduce the acceleration even further. But M201 is the G-code to use. You can put this in your start script and see if it reduces the bed shaking enough to help.

Dale

[jereywolf]

Thank you Dale!

[jdacal]

One other thing that might cause it which happened to me is if the extruder motor mount develops a crack the nozzle can swing back and forth. In my case the motor was spinning slightly inside the mount, this would cause the nozzle to swing from side to side as the motor changed direction. It was an overnight print and it got progressively worse during the night. But since they are tall thin pieces what Jim and Dale suggest probably makes more sense in your case.

[Capt. John]

Where's the clips that hold the glass to the bed? Those rubber corners need help.

[jsc]

Not to be argumentative, but I don't find I need the clips and have been running without them for a long time now. I found they introduced more of a bend in the glass, and also there's the chance I might jog into them.

[jereywolf]

Where's the clips that hold the glass to the bed? Those rubber corners need help.

Not to be argumentative, but I don't find I need the clips and have been running without them for a long time now. I found they introduced more of a bend in the glass, and also there's the chance I might jog into them.

I'm actually using four of these.

http://www.thingiverse.com/thing:391221

I printed them in Bridge. They stay in place and don't cause any issues when printing PLA with the bed fan.

One other thing that might cause it which happened to me is if the extruder motor mount develops a crack the nozzle can swing back and forth. In my case the motor was spinning slightly inside the mount, this would cause the nozzle to swing from side to side as the motor changed direction. It was an overnight print and it got progressively worse during the night. But since they are tall thin pieces what Jim and Dale suggest probably makes more sense in your case.

How I have fixed this problem so far is by increasing infill to 35% from 20%, and changing the placement on the glass bed. Rather than printing them side by side, I printed them one in front of the other. I think I avoid vibration caused by the extruder's movement in the X axis that way.