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Prints leaning

Posted by blt3dp 
Prints leaning
February 04, 2014 02:21PM
Hi, I'm printing with a Prusa v2 with Linear Bearings & Z Stabilizer, Printrboard w/Repetier Firmware and using Mac Repetier Host/Slic3r. It was working fine, I hadn't used my printer in a while and just came back to it. Installed Repetier Host/Slic3r (I had recently wiped/redid my Mac. Now I'm getting leaning prints.

I'm pretty sure it's not a mechanical thing. I've made sure both the X and Y axis are level and that they move freely and don't bind up. Same for the Z axis, it slides along the smooth rods nicely, and the threaded rods don't seem to bind up.

I'm still using XL Belts and Printed Pulleys. They're properly tensioned and they don't seem to miss a step. I do have GT2 Belts and Machined Pulleys as well as Aluminum Z couplers on the way.

Also verified the calibration on the Extruder as well as the Axis. Though I'll have to redo them after the new belts.

Here's a picture of the print. That hole doesn't look round, almost as if it's squishing it, but the other hole (not pictured, is almost perfectly round. I'm almost thinking it may be Slic3r slicing it wierd. Any ideas?

Edited 1 time(s). Last edit at 02/04/2014 02:41PM by FA-MAS.
open | download - leaning.jpg (395.9 KB)
Re: Prints leaning
February 04, 2014 02:42PM
Your frame is out of square. Something may have gotten leaned up against it or was bumped in some way.

Remember: 1. Square your frame. 2. Level your X-Axis. 3. Level your bed. In that order.
Re: Prints leaning
February 04, 2014 02:45PM
That's actually exactly how I verified everything. Made sure the table (flat glass kitchen table) was perfectly level, and performed all this on that table in the center.

I'll check it again though.

Edited 1 time(s). Last edit at 02/04/2014 02:48PM by FA-MAS.
Re: Prints leaning
February 04, 2014 03:01PM
The glass table / printing on a flat surface is good for checking if everything is "level". That is good for the bottom half of the printer. Your Z linear rods need to be at 90 degrees to your frame. Not necessarily the table. Don't use a bubble level to check for square. 1 degree doesn't show up on your level but it shows on the print.
Re: Prints leaning
February 04, 2014 03:57PM
I actually did do a ghetto spirit level (nut on string) and it seemed to be ok. But I didn't think to actually throw a framers square across the Y smooth rods and see if the Z smooth rods were perpendicular. I'll check that when I get home

Edited 1 time(s). Last edit at 02/04/2014 03:58PM by FA-MAS.
Re: Prints leaning
February 04, 2014 04:14PM
Actually, your Z rods need to be perfectly orthogonal to your bed for all Y axis values, and your X axis must be parallel to the bed. If your printer is perfectly aligned, it really doesn't matter if it is level with respect to the earth. If you struggle to level with a bubble level, and the work surface the printer is on is NOT level, you are really making things tougher on yourself. If you CAN level your work surface, it gives you a good reference point aligning the rest of the printer, but it is not strictly necessary.
Re: Prints leaning
February 04, 2014 05:12PM
@jbernardis: Aren't you just paraphrasing what I already said?
Re: Prints leaning
February 04, 2014 05:37PM
Yes, I did ensure that my glass kitchen table was level. I used wooden shims and leveled it. Should be a good base to verify everything is square and level. I'll check back later.
Re: Prints leaning
February 05, 2014 03:22AM
Just finished essentially taking the whole thing apart and putting it back together. The lower frame was square, but the right Z Axis Smooth Rod was way out of square with the rest of the frame, in X and Y directions. The Left one only a little in the Y direction. I also noticed a couple other mechanical things, seems one of my bearings on the Y Axis had seized, I actually had gashes in the Smooth Rod. I replaced them both and ensured it is moving freely. It's printing now and looks promising.
Re: Prints leaning
February 05, 2014 11:59AM
Finished printing, the print looks better as far as layer alignment and the fill looks better. But I still see the lean. I've noticed something though, even on the older prints. I'm printing Rostock Kossel Top Vertices and all the vertical walls are perfectly vertical, except for the end piece that I pictured in my first post. They're just thin little pieces with screw holes that come off the frame. Could it possibly be a cooling/shrinking or Slic3r issue?
Re: Prints leaning
February 05, 2014 06:01PM
@jbernardis: Aren't you just paraphrasing what I already said?

Upon re-reading, yes you are right. We are saying the same things.
Re: Prints leaning
February 06, 2014 06:38PM
Yes it can be a cooling issue. If it's uniform shrinkage all the way around it. It's leaning if you have space on the bottom of the print on one side and the top of the print on the other. Then again... How reliable is your square you're using???
Re: Prints leaning
February 07, 2014 12:27PM
I believe I got the leaning print issue resolved. I was upgrading the XY belts to GT2, and I'm not sure why I turned one of the Z threaded rods by hand, but I noticed the other one didn't turn as much. I looked closer and the vinyl tubing and printed coupler on that one were slippng. Good thing I had just gotten the aluminum couplers. I put them on and it seems to have resolved the leaning.

But, another thing I'm noticing is that the bottom layers, say the first 10 are shrinking. Pretty uniformily throught the entire print. I'm printing Ultimachine Natural PLA at 200, with the heated bed at 70. Should I print cooler? Also I had a cooling fan at the print, but I think it was too far away and not really cooling it, so I moved it closer.
Re: Prints leaning
February 07, 2014 12:43PM
Yes. For PLA, cooler is better. Maybe around 185c on the hot end and 60c on the heatbed. With a clean and smooth surface, you may not need to use the heatbed.
Re: Prints leaning
February 10, 2014 12:58PM
I've switched to printing on just my glass with blue painter's tape, heatbed was off and had a fan on the entire print. I also went to 185 on the hot end with a fan. Each time it would finish a line, retract, then start a new line, there would be difficulties starting the new line. Like the line started and then the end peeled up and dried. In some areas it caused it not to stick and start to peel up and warp a little. It looks like that's the only flaw I'm running into now, the walls are mostly perfectly vertical except for when that happens. Any suggestions?
Re: Prints leaning
February 10, 2014 09:18PM
Slap a new stepper motor in it.
Is the other edge not square either?
Re: Prints leaning
February 11, 2014 01:38AM
I've gone over the frame, again. Tripple checked everything and now I'm super confident it's all square. I'm printing a 20x20x60 cube now. It's about 1/3 the way up and it doesn't seem to be leaning. I'm surprised, the layers look perfectly aligned, even more than I've seen before. We'll see how it is when it finishes.

Edit, vertical alignment looks really good. But damn, Z wobble. It's actually not bad, only affects the front of the cube. Seems that's when the wobble rolls around. That's another issue though.

Edited 2 time(s). Last edit at 02/11/2014 12:00PM by FA-MAS.
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