Shifted Print

[BrayChristopher 36]

I have a LONG 30+ hour print going. The material is semi-flex. I sliced it in S3D.

But it shifted mid print. Boo. It looks like it is still stuck in place on the bed.

Everything looks fine and normal in the slicer preview.

I know a lot of people have asked about this already and step one seems to be "check all of the set screws on the pulleys".

But if the pulley set screw was loose, wouldn't it be shifting all over the place? Not just once?

I have a fan blowing on the controller board.

Any ideas other than the set screws. I will check them when the print is done.

[BrayChristopher 36]

Here is my second attempt.

I slowed the print down a little and I reduced the amps to the XY motors.

And it still shifted at the same height! It did shift a little more this time.

Since it shifted at the same height, I am now thinking that this is an issue with the slicer.

Also, when the print finished, the bed did not lower and the downward fans stayed on (all night).

I am going to post this question to the S3D forum as well.

[00D00B 58]

Hi,

I think S3D could be a problem you're right

Try at least to print it (or even a smaller version) in PLA to be easier and make sure you do not have this problem.

I guess that Cura could do it well

[neotko 1,417]

S3D basic profile is the worse. Try this one from @frederiekpascal

https://ultimaker.com/en/community/22594-simplify3d-top-layer-quality?page=last#reply-158298

Ofc adjust the temp/retract that fit your material

Edited October 4, 2016 by Guest

[Torgeir 242]

Hi Bray,

This is kind or rare, -sure the slicer program can do strange thing, but so can the hardware..

A few missing "full step" on the x-axis at a certain spot will do the same thing!

This is very true as the firmware only can synchronize at the X/Y and Z end switches, from there on it is only the number of steps that's the true reference.

Also, is your R/H stepper (the X-axis) very hot, or just hand warm? Compare with the Y-axis stepper.

Did you try to print this object (edit:) "sliced" in Cura without this issue?

Just a thought.

Thanks.

Torgeir.

Edited October 5, 2016 by Guest

[neotko 1,417]

Oh men I'm so busy I overskipped that detail XD

Indeed no matter the slicer the shift is a mechanical issue. Make with a marker a mark on all the x or y (depends on which direction the shift goes) including the motor pulley. Print and a soon you get the shift check all the makrs to find the source of the issue.

[BrayChristopher 36]

Try at least to print it (or even a smaller version) in PLA to be easier and make sure you do not have this problem.

 

I printed a half scale PLA version and it came out perfect. Now I am in the midst of printing a full scale PLA version to see if I get same shift.

Hopefully it doesn't do anything too crazy in the middle of the night.

[BrayChristopher 36]

The full scale PLA version came out fine. 19 hours.

The stepper motors are hot, but I've printed longer (48+ hour) prints before.

Maybe need to add some heat sinks.

I think my next step is to try the Semi-Flex again with slightly different settings or try Cura.

[Torgeir 242]

Hi Bray,

This is one of a special thing..

The last print looks very nice, question is; is this objects height less that the height were the "error" occurred on you full scale model?

Cause the only common thing here is the Z-axes, so this is just a theory;. Suppose that the bed does miss two step -or more (hanging somehow), then assume a little lo torque on the X-stepper or high friction when hot(?). When the extruder then hit the print object, the X-stepper miss some step due to this collision (and now has got an offset), the heat bed move a little down and the printing process continue printing with this X-offset.

A monitoring of this problem would be interesting to observe.

Well, this is just a little theory, but.. Who knows.

Thanks.

Torgeir.

[BrayChristopher 36]

The last print looks very nice, question is; is this objects height less that the height were the "error" occurred on you full scale model?

 

The GRAY part is full scale PLA. The same scale as the RED and BLACK parts. (I never took a picture of the half scale PLA part).

The PLA print took about 19 hours.

The Semi-Flex prints took about 36 hours each.

 

A monitoring of this problem would be interesting to observe.

 

Yeah, I wish. But is just isn't practical to sit and watch it.

[Torgeir 242]

Aha, sorry I missed that..

I like gray, -but is it that much better...

36 hours, Oh me..  

Then this is even more strange.

Anyway, good luck -maybe remove the cover over the X stepper..

Thanks.

Torgeir.

Edited October 5, 2016 by Guest

[BrayChristopher 36]

Anyway, good luck -maybe remove the cover over the X stepper..

 

Done and done. Stupid covers.

[BrayChristopher 36]

OK. I may have found the problem.

After printing two more successful PLA prints and another (different model) Semi-Flex print... the printer completely freaked out.

The printer started clicking like crazy. Not stepper clicks. The belt was skipping. I killed the print, but it was still trying to home the head and the belt was still skipping, so I had to kill the power.

The rear "X" linear rod was sticky in the middle of it. I have no idea why.

I wiped down all of the linear rods with acetone and then applied a bit of sewing machine oil.

This might be completely unrelated. I doesn't make any sense that this problem would have caused two 36 hour prints to glitch at the same height. But whatever.

[stuc3386 0]

BrayChristopher - were you able to solve the shifting? If so, what was the culprit?

[gr5 2,173]

That's almost always caused by a loose pulley.  Each axis has 6 pulleys with belts around them and connected to steel rods.  There is a little set screw to connect the pulley to the rod.  That needs to be tightened.  A lot.  So much that the hex tool is twisting.

 

90% of the time that is what causes these steps.  Figure out which axis is slipping and then tighten the 6 pulleys for that axis.  It's almost always the pulley on the stepper motor which is the hardest to get to.  If you need to remove the cover over the stepper it's held on by only 2 screws.

[stuc3386 0]

Thanks! That one is a pain to get to...! I modified a key to get in there but given your tip I'll remove the cover and get it better.

[BrayChristopher 36]

8 hours ago, stuc3386 said:

BrayChristopher - were you able to solve the shifting? If so, what was the culprit?

 

My issue was not loose set screws on pulleys.

 

For some reason, my linear rods get "sticky" over time. I have NO IDEA why. The printer sits 10 feet away from me in our office. And I have an acrylic enclosure for it.

 

So every once in a while I wipe the smooth rods down with acetone and then apply a little sewing machine oil.

 

 

 

 

I don't know if this is part of the problem or not, but I have also taken some steps to keep the motors and electronics cooler.

 

I keep the printer up on feet. 

https://www.thingiverse.com/thing:966936

 

I made a "mesh" enclosure for the electronics to let them breathe easier. And I added a cooling fan.

https://www.thingiverse.com/thing:2512743

https://www.newegg.com/Product/Product.aspx?Item=9SIA8J233K6989&cm_re=ac_infinity-_-9SIA8J233K6989-_-Product

 

I took the stepper motor covers off and left them off.

 

 

[stuc3386 0]

Thanks for following up :) I think a fan on the PCB may be a good idea as we just had to replace the A4988 on E1 after doing the UM2E to UME2+E upgrade

Edited June 7, 2018 by stuc3386