neotko

Btw searching for other stuff found an answer to this old post. http://www.wyman.fr/autolevelling-bltouch-ultimaker-original/ So it’s in french. But seems pretty straightforward.

I have also printed with the standard UM2 slicer settings, so that's not the problem... I mean that you check the firmware default accel/jerk settings. But indeed it’s weird

What’s the acceleration/jerk settings? Maybe jerk is way too low than the 20 default?

Yea, that speed settings where for old Cura 15.X or lower. The old version used 0 as a way to set all the print speeds the same as the base print speed. On new cura 2.x that doesn't work that way, you should change the 0 for the base print speed that on your screenshot is 40mm/s

I would check the gcode to see how many movements/second are happening there. That's the classic effect of the board stuttering the planner. If that happens again if you slow down the speed to 50% then it could be other thing. I seen this behavior also happening on latest s3d 4.0, it has a bug that inserts lots of small extra extrusions making the buffer stutter.

Well the window washer trick was for Glass. With a sheet indeed most probably won’t work.

With 8000h use maybe it’s time to check the tooths of the belts. I got one damaged not so long ago. Maybe someone else has other ideas of stuff to check?

Then check the belt tension. Maybe they are too loose. To fix the tension unscrew the pulleys and in theory they will retight with the spring inside the slideblocks. Also, check if there’s no oil on the belt/pulley contact with belts, just in case that’s making them slip.

Did you pause with a cura gcode or a s3d gcode? I ask because that sounds is the head trying to go beyond the limit when the x/y offset is set by a gcode. If you use s3d you need to activate the gcode offset For the other issue. That I don’t know

Did you tighten the motor pulley? The ones less accesible

Cold you make a picture of that? is it sanded or what is it like? If it was sanded - wouldn't this result in an feature like a buildtak mounted? Here is a picture. It shows a close up with a nickel on the glass to help you understand the scale. The surface is smooth-textured as you can see. I don't know anything about buildtak. Wow that’s like a kitchen ceramic glass? Mine is invisible to the naked eye.

Exactly like @nicolinux said. It works with pla/flexibles/greentec you can remove even using strong adhesion Hair Spray. I do that every day to speed up & I can avoid removing the plate to keep the bed level intact

S3D guys have the most horrible support staff. So I would expect a very crappy copy/paste. Yea I would test 3.1 or check the gcode to see if there’s a lot of moves for very small distance. BCN3D afaik also has a slow chip like um boards, so it can stutter pretty fast if the alicer is making a bad gcode.

Interesting debug the guys at Duet3D does with 4.0. Clearly on some cases new 4.0 can cause massive amount of lines without doing much, making the machine stufter (movement planner has a buffer limit/second). If this can stufter a Duet3D, imagine the amount of blobs it could cause on a UM2 board. https://www.duet3d.com/forum/thread.php?id=2209&p=2 So for now I would try to check what settings make S3D 4.0 cause this increase of useless movements, and check the gcode to debug the origin. Ofc for now unless it works, I would try to move production (critical/time/prints) to 3.1 S3D until they fix that

Maybe the second nozzle isn't getting a perfect Z calibration. Can you try doing a manual bed calibration and printing again?

I suppose that's the Z retraction for each layer, ofc removing it would create more blops. Maybe you can try to play with this options Go to Layer tap Change Start points from Optimize etcetc. To Choose Start point closest to specific location. This way to could change the start/end of each layer to keep the Z scar on another spot. Ofc, also you can choose to ramdom it, with 'Use random start points' but also that increases the travel distance for the print. Depends on the object, it might or not help much, but worth a try. If you want to remove that retractions you could disable the 'Force retraction between layers' on the Advanced tab. But ofc, when changing from one to other layer it might increase the chances of a blop because the head will remain static while changing Z for a few microsecs.

LOL yea I explain myself really bad most of the time. What I mean.. is that S3D default option is like this: That's just bad, bad bad bad and bad. It should be 1.00 instead of 0.90 If you enable the 'Auto' for Extrusion Width, it just changes it to a fixed value that he likes, and that value doesn't help anyone. Ofc you can change that Extrusion Width from 0.35 to 0.45 even using a 0.4 nozzle. For most of the prints you will get great results without any problem. So the 'auto' doesn't do anything automatic, nor changes in real time to fit the needed extrusion. But 4.0 now has a Single wall that works quite nicely, to make thin walls that adjust themselfs atuomagically, that's on the last tap and it requieres some tests to control it fully, but with the gcode views you can see the effects on the print before printing it.

JESUS posted the answer 3 times and all erased.. Ok again.. I don't see how acceleration can affect that, you can use M204 gcode to change it to see any effect on it. I think you have the highend/lowend of the endstops inverted and the motor keep's going down to find an endstop that isn't there

In S3D auto doesn’t do a thing. Set all to the real nozzle size if you want it to be 0.40 If you adjust extrusion width it will extrude to match the extrusion widthselected. So if with a 0.4 you choose 0.35 it will print like a 0.35 making more passes to fill, etc. I use this quite a lot to adjust different parts of the print that needs different nozzle extrusion all with the 0.40. I can go down to 0.31 or up to 0.5

Well it should move unless your stepper cables pairs are wrong or not making contact. You can try to printrun/pronterface by usb and just move up/down to see if it’s just moving in reverse (hense the screaming noise) or its a faulty motor?

Z microstepping is set by a switch (not firmware) so probably you have it at default (no switch) 1/8 microstepping Also without knowing more about the mods is hard to guess

Yea Simplify3D has the most horrible support. I got to mail 3 timea for them to answer with a non-copypaste about 3 bugs I found on 4.0 even when I did collect all the info and files. This is on the bcn? Maybe you need to play with the temperature and watch if the heads are fluctuating? About blobs. Try to enable ‘only retract when ‘ on advanced, this way with ‘avoid crossing’ you can get rid of most of the retractions that can cause blobs. Ofc then you might get scratches on top layers. It has a bug (imo) that even with combing active it doesn’t move from one perimeter to another without retracting IF the ‘only retract if’ is disabled. I found a work around for that but they killed it with a bug on 4.0

Yea https://ultimaker.com/en/community/23401-inside-the-ultimaker-3-day-4-electronics#reply-160875

Well all steppers do the error so I preferred to use it on all. I didn't noticed any change on Z level or extruder power so it's all ok. At least for now

Made a small practical manual explaining the obvious stuff, to help the users that are afraid of touching their machine. https://ultimaker.com/en/community/50647-manual-how-to-install-tl-smooth-zebra-strippes-fix-umo-um2-um3