Random Crashes
Had my MK3-S for about a week. Using the Prusa PLA, that came with the kit, I've printed 3 of the items that came on the Prusa SD card, the whistle, Logo and Bottle Opener.
I pulled down a few STL files from Thingiverse and have tried 3 different prints. A couple are AA and AAA battery holders. With of these had around 27 hour print time. Both knocked the print off the bed after 20 hours of printing.
Did another simple print, this morning. It put down about 5 layers and then it too came off the bed.
The Fail Stats indicate I've had 1 X axis failure and 5 Y axis failures.
All projects had the G Code generated in the latest Prusa slicer.
Are my failures g-code based or hardware.
Thanks
RE: Random Crashes
A print coming off the bed can happen if your first layer for whatever you are printing doesn't go down well, and has adhesion issues from the start. A print can also come off the bed if the part warps while printing - a log of designs were never designed to be printed, and a lot of the ones on the thingie were not ever printed by their designers - buyer beware.
Each and every shape is a new challenge, in my opinion. I have learned to always watch my first layer carefully and adjust the live Z value from the console as the print starts. It takes some practice to recognize a good first layer - but if your skirts are loose, or coming off the plate - if the edges of the lines going down from the print head are sliding or curling - move the head closer to the sheet (increase negative - it's ok to be aggressive.
For warping, you need to examine the parts that fell off of the bed. If you place them back on the bed, is the bottom perfectly flat? Or had the shape curved as the print got taller? If the part won't lay 100% flat - no rocking - try adding BRIM in your slicer settings - again be agressive (5 mm is not uncommon as a good starting value). If your prints warp and fail again, you can increase the "stick" by greasing your print sheet with the glue stick that came with your printer. It'll make for a bit more of a cleanup, but it'll hold most parts pretty firmly.
RE: Random Crashes
I suggest looking at https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-assembly-and-first-prints-troubleshooting/life-adjust-z-my-way/ and re-doing your first layer calibration. Also, make sure your PEI sheet (assuming you just non-textured sheet) is really clean - use dish soap and hot water, avoid touching the sheet with bare hands, dry it with kitchen paper paper.
RE: Random Crashes
Thank you for the replies. After I posted this, I tried to print the Prusa Test Cube, 3 times, but couldn't get the first couple layers to stick on each try.
I then tried the Bench, from the Prusa SD card. The perimeter layer didn't appear to stick well, but the bench layer seemed to go down well.
I recorded it on a Wyze camera and made the short video of it again failing after 2 hours. There are photos of the result at the end of the video.
Skip to around the 2:40 mark to see it fail.
It looks like there is a collision.
RE: Random Crashes
@chris874
Your initial live Z is way to high. Your prints are popping off and failing.
RE: Random Crashes
What @dragon1291 said. The last frame of your video that shows the bottom of your benchy shows that your live-Z is WAY too high. This is off by quite a lot. Your video shows that with what little adhesion it has, once the nozzle gets to a sufficient height to gain enough leverage on the print, the print pops off the bed. There is no reason to print anything else until you resolve this issue.
Follow the life adjust Z method that @hli suggests. This is a superb method.
NOTE: all new 3d printing people go through this phase! 🙂
Stock Prusa MK3S+ built from kit on 12/2020
OctoPrint, typically print from a drybox, no enclosure yet
Printing proudly since 2011
RE: Random Crashes
@dragon1291
Thanks, I dialed it down doing the first layer calibration, several times, until the results of the rectangle patch started to look worse.
But doing actual prints, I agree, it looks like it's not low enough.
I guess, being a total noobie, I don't understand how something, like my Benchy example, can print for 2 hours and then just easily pop off.
On the first project where this happened, it printed for 21 hours and again came off with no visual reason why that happened.
Could this be an issue with the bed heating and cooling, during a print?
RE: Random Crashes
@chris874
Until you fix your live Z, there is no other issue you should be thinking about. 🙂
Follow this guide: https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-assembly-and-first-prints-troubleshooting/life-adjust-z-my-way/
-Matt
Stock Prusa MK3S+ built from kit on 12/2020
OctoPrint, typically print from a drybox, no enclosure yet
Printing proudly since 2011
RE: Random Crashes
Thanks, I followed @hli suggestion and did the test outlined by Jeff Jordan.
I completed two tests, the first yielded a layer around .25 to .29.
I adjusted the Live Z and the second test was .19 to .22 depending upon where I measured the sample square.
Guess my bed is not quite level.
Thanks again all for helping a noobie with your knowledge base.