Filament Detaches From Bed During First Layer
 
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roy.l
(@roy-l)
New Member
Filament Detaches From Bed During First Layer

Hi,
After receiving the printer about two weeks ago, I assembled it and got it working without any problems, to the point that I managed to print the "adalinda" model that came with the SD without issue that day.
(I also printed a couple of models that I sliced myself, so it's probably not an issue with the Slic3r settings).
After a couple of days that I didn't use it, I tried printing a variety of models, most of which failed because the filament would detach from the bed and stick to the nozzle. I tried raising and lowering the PINDA probe, increasing the bed temperature, running the calibration procedures multiple times, including updating the firmware version, and cleaning both the bed and nozzle with alcohol.
The strange thing is that the V2 calibration model that came with the printer often detaches at the bends, although not always at the same bend each time...
I also tried printing JeffJordan's V4 calibration model ( http://shop.prusa3d.com/forum/prusa-i3-kit-building-calibrating-first-print-main-f6/life-adjust-z-my-way-t2981.html ), which almost always works without detaching, although rather than the expected film, it results in a square composed of individual strands.
I'd appreciate any suggestions

Posted : 15/07/2017 5:14 pm
aaron.s5
(@aaron-s5)
Noble Member
Re: Filament Detaches From Bed During First Layer

Sounds like your "live adjust Z" is not set correctly for your first layer.

See the "Life Adjust Z - my way" thread under Calibration, and read the first 6+ pages.

Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…

Posted : 15/07/2017 10:46 pm
roy.l
(@roy-l)
New Member
Topic starter answered:
Re: Filament Detaches From Bed During First Layer


Sounds like your "live adjust Z" is not set correctly for your first layer.

See the "Life Adjust Z - my way" thread under Calibration, and read the first 6+ pages.

I tried quite a couple of times to fiddle with the "Live Set Adjust" setting, and indeed found that setting it in the range of -80µm to -100µm did help a bit, although the filament would eventually detach anyway.
Setting it higher (closer to 0) would just make it detach faster, while setting the value lower (a larger number, I tried up to -300µm) only made it more likely to stick to the nozzle while moving.

Although something particularly strange that I'm now starting to see is that the filament is more likely to detach while the head is moving on the X axis than the Y (based on the V2 calibration model, and a number of cubic ones with concentric layouts). I checked the belts, and both seem properly tensioned.

Posted : 16/07/2017 5:30 pm
aaron.s5
(@aaron-s5)
Noble Member
Re: Filament Detaches From Bed During First Layer

It sounds like your PINDA sensor is at very close to the same level as the nozzle (thus your very low Z adjust values). It should be higher than the nozzle by about 0.6mm (about the thickness of a credit card). You may want to move the PINDA up a bit in it's holder, and then use this method to set it correctly:

0) Do an XYZ Calibration. This will zero your Live Z Adjust, but will measure how flat your bed is and compensate. If this fails, then your PINDA is too high. Keep paper under it so you don't scratch the bed, and watch it. If the paper catches, stop it right away.

1) Get the Live Adjust Z roughly correct.
a) Set Live adjust Z = 0.00. Make sure PINDA is above nozzle tip by <1mm but above.
b) Do a Calibrate Z. (Head must be clean of drips and lumps).
c) Do a Home. This leaves the head at Z=0.15mm
d) Use Setting -> Move Axis X and Y to get in the approx center of the print space. DONT TOUCH Z.
e) Put a piece of printer paper under the head. Printer paper is approx 0.1mm
f) Wiggle the paper while adjusting "Live Adjust Z" (in settings) until the paper just starts to drag on the paper.
g) Back off a bit (50) on the Live Adjust Z"

2) Get it dialed in real well.
a) Print using "Calibration_surface_PLA_75x75@200um_v4.gcode" found in Jeff's "Life Adjust Z My Way" Thread
b) Repeat until you have a nice test print - all stuck together and one nice clean sheet.

This takes a little while, but is worth the effort. Once the first layer is good - the rest follows.

Also, make sure the bed is VERY clean. Finger oils and other contaminants prevent adhesion. Clean with as pure an isopropyl alcohol (IPA) as you can buy. I sometimes do Windex followed by Acetone followed by IPA, but only if I used things on the bed - like glue stick or the like.

Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…

Posted : 16/07/2017 7:35 pm
Dboard52
(@dboard52)
New Member
Re: Filament Detaches From Bed During First Layer

After some experience with print detachments I found that along with the live Z adjust, it is helpful to go slower on the first layer, about 60% speed which can help stick parts down well especially on long prints. Using a brim can also help.

Posted : 20/07/2017 7:41 am
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