hotend acting cloggy

hi all,

i have the sudden issue on a fine print - its a grid out of single filament lines,
that it randomly cloggs and uncloggs.
I printes solid things e.g. iamburnys gearset - no problem as soon as it
retracts often it seems to clogg. I tried temperatures from 235 to 260 C°
also varied the speed - seems to work better 12mm/s but thats kinda low
compared to PLA with 35mm/s.
Pushing ABS by hand gave me the thought that i printed to fast, also the
Filament got grinded down by coldend running automaticly.
Sometimes the printer makes this blobing sound like a small bouble would pop.

I cleaned the hotend it is a E3D clone that has been running well since 2 years
PLA and ABS. 0.4 nozzle
Using the spring loaded extruder from mason stonehenge.
I am kinda at the end of my knowledge any one got ideas?





Edited 1 time(s). Last edit at 07/20/2017 12:20PM by redblunt.

Possibly your filament has been left out and absorbed water. This creates "popping" sounds and breaks in the extrusion. It can be dried by storing out of a bag in a warm dry cupboard (airing cupboard) for a week or two, but a faster solution is to use freshly bought & hermatically sealed filament.

Dave

Erik

thanks Erik
Ill try to dry some in the oven and test it out.
thinking about it we had a lot of rain this summer.
My filament does not look that bad but it
does not break as easy as usual it seems to bend more

kind regards
red

i put my rolls into the oven at 75 - 90°C for about 4 hrs
one roll had about 300g of filament on and the other close to 1kg
still hearing pop sounds -.- and the print is breaking off.
ill try to get some new filament in the meanwhile i store the
rolls in two plastic abgs with a anti moisturebag there is
a relative humidity of 20% i hope in a couple of weeks it can
be used again.

I have never had problems with moisture on abs. If you find bubbles like the pictures Erik shows. It can be a manufacturing problem. I have had that problem on one of my rolls. I sent it back and got a new one.

Try to cut filament and see if you find bubbles. There should not be any.

i cut the unextrudet filament several times and did not find any bubbles!
Extruding the wet filament gave me small bubbles not
bad as Erik showed but still noticable.
I have my printer set up in a 10m² room with a lot of other
technique when everything is running and its like 30°C
outside its about 35°C inside and i sweat like a bull.
And the hotter the air the more humidity it can have.


I just got a new roll of abs wich works great. Like day "one"

Did I say it worked?
the first two layers no problem then it started stopping again.

Ill reduce the speed of infill down from 35mm/s to 31mm/s
and the increase the heat from 245 to 248°C
and report back

Edited 1 time(s). Last edit at 07/24/2017 09:36AM by redblunt.

dont know what happend back there but going slower seems to work

still only on the first layer it stop printing occansionally.
Any one got Ideas?

Edit: Tightened the coldend so it grabs more agressive didnt seem to change much
Speed is as said above and temprature set to 246°C; +-1°C whily printing



Edited 1 time(s). Last edit at 07/24/2017 01:27PM by redblunt.

Could you first layer be too low? - what happens if you set first layer zero, is the push form extruder able lift the nozzle? - do the hotend swing freely around the smooth rod?, any extra weight added to the hotend recently?

Erik

Look like its kind of repeating in length of filament, anything strange with the big extruder gear?

Erik

Quote
Could you first layer be too low?

First layer ist set to 0.3mm as all layers.

Quote
do the hotend swing freely around the smooth rod?

Hotend can swing about 3mm up.

Quote
any extra weight added to the hotend recently?

No extra weight.

Quote
what happens if you set first layer zero

You mean in the slic3r setting? Did not try that

Quote
is the push form extruder able lift the nozzle?

Dont think so but i actually did not try with this hotend.
As I remember the original hotend was not able to.


Might my axis compensation be to high?
Because on the picture the problem zones quite look
like beeing regularly:

M556 S77 X0.15 Y0.5 Z0.6

Quote
Look like its kind of repeating in length of filament, anything strange with the big extruder gear?

Extruder gear got printed out couple weeks ago and looks normal to me also how it spins
when turning it really fast.

Edited 1 time(s). Last edit at 07/24/2017 01:41PM by redblunt.

Quote
redblunt

Quote
Could you first layer be too low?

First layer ist set to 0.3mm as all layers.

Quote
do the hotend swing freely around the smooth rod?

Hotend can swing about 3mm up.

Quote
any extra weight added to the hotend recently?

No extra weight.

Quote
what happens if you set first layer zero

You mean in the slic3r setting? Did not try that

Quote
is the push form extruder able lift the nozzle?

Dont think so but i actually did not try with this hotend.
As I remember the original hotend was not able to.

..and zooming in on the picture it do not look as that was the problem, more like the flow varying in a repeating manner

Quote

Might my axis compensation be to high?
Because on the picture the problem zones quite look
like beeing regularly:

M556 S77 X0.15 Y0.5 Z0.6

No, should not show up like that

Quote

Extruder gear got printed out couple weeks ago and looks normal to me also how it spins
when turning it really fast.

Did the printer work before you made that change (and took apart the extruder)? - I would concentrate on that part, especially about the repeating waves, put a mark on the big gear wheel and see if it correlates with the waves in the laid down filament

...other thing about the extruder, the ptfe tube could move forward and pinch the filament, hobbed wheel loose, forgot to insert the opposing bearing again (it has happened LOL) - non of this would make that repeating patten though...I think unless the hobbed wheel is out of wag

Erik

ok, extruding more manually i noticed the problem occurs always on the same spot
marked on the big extruder gear.

The ptfetube inserting ito the hotend seems to be ok as i cut the inside out pretty much.

The black partial circle does not feed correctly.
The gears themselfes seem to grab good into each other.



Ill take the hotend to pieces and investigate further

The big gear side of the coldend is kinda slid out but I guess this is not the actual problem beacause
hobbed wheel does not seem to run very circular.


..so I might decrease distance between the hobbed wheel and the bearing

..or make the bearing thicker

..or try a new screw

ok ill try to setup the original piece and print a spare with it
to check wether it is running.

can anyone supply a link with a better working coldend
than the original one from reprap?

ok ill try to setup the original piece and print a spare with it
to check wether it is running.

can anyone supply a link with a better working coldend
than the original one from reprap?

Quote
redblunt
The big gear side of the coldend is kinda slid out but I guess this is not the actual problem beacause
hobbed wheel does not seem to run very circular.


..so I might decrease distance between the hobbed wheel and the bearing

..or make the bearing thicker

..or try a new screw

That could be it! - notice on the picture how the bearing (with no filament installed) bottoms out on the alu front part of the stepper, its very close to same with filament between, I noticed this long time ago and filed the alu part under the bearing down half a mm (on my working extruder, not the one on the picture yet)

I'm quite sure that will fix it (fingers crossed)




Erik

ok thank you very much Erik
I will reprint the parts and modify the motor.
Finally its running without any issues