Component print requires unloading/reloading filament every couple of layers, for no good reason?
 

Component print requires unloading/reloading filament every couple of layers, for no good reason?  

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sehix
(@sehix)
Active Member

After a little time away from printing (life/work sometimes gets in the way), I decided to print a filament spool holder that better fits my needs. So far, so good. I chose graham01's anti-tangle spool holder (Thingiverse thing:2479238).

The stl files seemed fine, PrusaSlicer ate them happily, and put out gcode files to print.

Everything went swimmingly, until the upper two cross beams ("sh arm cross beam top v1"). Most of the other pieces printed in two colors; no problem. Unload, switch, reload, continue...

The upper arm cross beams seem to want to switch filament every layer, maybe every third layer. One loses count.

I can't see anything that would cause it in the stl file (using FreeCAD), nor in the generated gcode. Anyone have any idea of cause, a fix, or a workaround? I can't even find any instances of filament change-related Gcodes in the gcode file, which doesn't mean they're not actually hiding there.

Any ideas?

PrusaSlicer : Version: 2.1.0+
Build: PrusaSlicer-2.1.0+-201909160907

Prusa i3 Mk.3, firmware 3.8.1 MK3

MacOS 10.15.2 (Catalina)

 

This topic was modified 11 months ago by sehix
Posted : 04/01/2020 2:54 am
JoanTabb
(@joantabb)
Moderator

Could it be false triggering of the Filament Sensor?

try again with the sensor turned off

Regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 04/01/2020 9:36 am
sehix
(@sehix)
Active Member

@joantabb

Might could be. Although it's the only file that behaves that way, and different filaments don't behave differently.

I'll give it a try when I get some time.

Posted : 04/01/2020 4:21 pm
sehix
(@sehix)
Active Member

That turned out to be a useful workaround. Whatever the cause of the innumerable filament reloads, turning off the sensor ignores them, and the pieces look to be printing just fine.

Thanks again for the workaround.

Now to figure out what triggered the problem in the first place...

Posted : 04/01/2020 11:37 pm
JoanTabb
(@joantabb)
Moderator

is this mk3, or mk3S?

Joan

 

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 05/01/2020 1:39 am
sehix
(@sehix)
Active Member

@joantabb

Mk3, as mentioned in the OP; haven't upgraded yet.

Posted : 05/01/2020 3:32 am
JoanTabb
(@joantabb)
Moderator

@sehix

the Mk3 with the original filament sensor suffers from a couple of issues,
it can accumulate Dust in the sensor chamber, there is a port on the right hand side of the extruder that allows you to insert an Air Duster pipe and blow the dust out...  
this port should be covered with a small block of plastic... if the plastic is missing, light can get in and upset the filament sensor...

also the sensor tends to get upset by clear filament, translucent filament, Shiny filament and green filament... apart from that' it's quite a good sensor... 

some people update the extruder to use a ball bearing between the filament and the sensor like this https://www.thingiverse.com/thing:3223513

regards Joan

This post was modified 11 months ago by JoanTabb
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 05/01/2020 10:39 pm
sehix
(@sehix)
Active Member

@joantabb

Mine has all the bits in the right places. It just happened that that one single model showed the behavior noted. Every single other one I've printed has been just fine, including every different filament I've loaded into the innocent machine.

There's almost certainly something pathological with the stl model, or the gcode derived from it.

A most useful workaround, in any case.

Posted : 06/01/2020 12:30 am
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