Hot End smashes into print sometimes

[velocilobster]

Hi,

I keep on having intermittent issues where my hot end essentially slams itself into my print/bed. This has happened both in the same place on a print, and also has succeeded where it has done this on a previous attempt.. This is always an unrecoverable issue, and the effector platform keeps on trying to go down. It also appears to happen in the same area in one print, and other prints that have failed will sometimes work.

I am assuming this is what skipping a step means? How can I prevent this? Is this caused by my slicer or is there a bigger issue?

Thanks

[BenTheRighteous]

Generally it's because you're trying to print close to the edge of the bed and your travel move speed is too high.

[velocilobster]

The print on the top (first post) was going 30mm/s, 100 micron, 180mm wide, 20% infilll. The error happened the first time at about 98%

I scaled the print down to 120mm wide, 100 micron, 20mm/s, as well as a 30% infill and it happened again on approx the 4th layer.

Is this still too fast?

The model was put together in tinkercad, but this has happened to files I have gotten from myminifactory as well as thingiverse. is there a chance that I have been unlucky with STL files?

Also, I have noticed that I need to calibrate my X axis every time this happens, sometimes my Z height changes a bit...but it is usually within 0.03mm of where it should be, which i account for other variables.

[Mac The Knife]

travel speed and print speed are two different settings. travel speed is a fast rapid move to the next area to print,

[velocilobster]

Sorry, I am still learning the ins and outs.

My travel speed was initially 75mm/s and I just changed it to 50mm/s.

Is this still too fast?

[Mac The Knife]

75 mm/s shouldn't have been a problem...

[velocilobster]

Currently my printer is plugged into a surge protector, I am more than willing to try my UPS if anyone thinks that might help, just don't want to turn my server off unless I have to. I am thinking there a chance that my issues could be occurring because of an abnormal amount of incoming power? I'm thinking it's either that, incorrectly configured firmware, belt tension wrong, or maybe my Rambo is having problems.

I have done about 5 failed prints (for other reasons), 2 successful, and this impossible to replicate issue has not happened since I last posted. I am just 100x more stressed whenever I leave the room for more than 5 minutes and the printer is running.

[BenTheRighteous]

If your print speed is appropriate (seems like it is), then belt tension could be the next most likely culprit - I'd check that, make sure nothing came loose.

[jesse]

Try using z-hop / z-lift. It raises the printer nozzle slightly while it's being moved.

[3D-Print]

As noted above, have you checked to make sure your belt tension is equal and tight. I had the problem and after I tightened end my belts the problem went away. (http://forum.seemecnc.com/viewtopic.php ... =50#p62165)

Any slack in the belts result in a shift in the head when it changes direction (that is when my problem occurred) especially with a large print that was at toward the edge of thebed. Increasing the Z-height helped as did slowing down my speeds, but until I tightened my belts is still had intermittent problems.

[velocilobster]

I feel as if they are maybe a little overtightened, that was one thing I was incredibly concerned about when building, and took extra care to make sure they were all equally taught.

When pressing on the belt by the stepper motor gear there is not a lot of slack, pressing between the stepper gear and the bottom idler, the belt probably only moves 1-2cm.

I did adjust the tension a little bit on a belt that I thought was too tight and the problem hasn't happened since...but that means nothing in my situation.

Will overtightening do this? I can upload a video later when I get home and I can show how tight I have my belts.

[velocilobster]

Okay, nevermind on the video...I wouldn't be able to fit my phone and get enough lighting in the area I was talking about anyways.

For now, let's just put this on hold as I have put about 20h of printing in so far with no issues since this was posted. I will post updates here if I find anything or think I figured out what is doing this.

Thanks.

[velocilobster]

Just to update, I believe this was caused by one of the tensioners at the top of the belt on my Y axis not being secured all the way.

Although the belts were tight enough for the printer to work properly, I believe the loose tension bolt would allow the belt to bounce or slip off the idler with a large enough movement from the Y axis.

And to help anyone else who may need a diagnosis for another related problem: Tightening the tension bolt also seemed to fix problems with my effector platform "jittering" when moving as well, especially when moving from home to the build plate.

[ZakRabbit]

Beautiful! Thank you for giving the fix!