Issues ejecting blobs

maybe you should post your code.

Just this, repeating over and over again

G28 X
M907 X850
G1 X200 F12000

G1 X200 F12000
G4 S0
G1 X250 F12000
G1 X249.6 F1000
M107
G92 E0
G1 E0.8 F2100 ;issue
G92 E0
G1 E40 F200 ;1st purge
M106 S255 ;blob cooling
G4 S12 ;blob cooling
G92 E0
G1 E-0.8 F2100
G1 X240 F12000
G1 249.6 F3000
G1 X240 F12000

G1 X200 F12000
M107
G4 S0

G1 X200 F12000
G4 S0
G1 X250 F12000
G1 249.6 F1000
M107
G92 E0
G1 E0.8 F2100 ;issue
G92 E0
G1 E40 F200 ;1st purge
M106 S255 ;blob cooling
G4 S12 ;blob cooling
G92 E0
G1 E-0.8 F2100
G1 X240 F12000
G1 249.6 F3000
G1 X240 F12000

Hi @mike-herman,

Sorry for the trouble you're having. Would you mind please uploading photos of your setup? The more the better. from the top/front/left side/extended and retracted.

A video as well would be even more helpful.

Also, how many springs are you using?

@bigbrain3d - I am using 4 springs

Here is a video link: https://www.youtube.com/watch?v=lZqRRqI5200&feature=youtu.be

Here are some images - https://imgur.com/a/vBQxrze

@mike-herman

I see 2 issues. 1) small issue is that the groove in the washer is not pointed straight. Try turning the washer so the groove moves to the left a little so that the groove points straight out from the catcher.

and the bigger issue 2) is that the fan is still blowing during the first few seconds of creating the second blob. This causes the filament to cool too while it's being extruded and instead of squishing down it builds the blob up. This makes the fat part of the blob higher than the tac and, since the fat part is larger than the opening of the tack, it gets stuck. See attached image.

You need a longer delay after the fan turns off and before the second blob starts being extruded so that the fan is completely off. Try this:

;**Begin purge test**
G28 X
M907 X450
G1 X200 F12000

M107 ;turn off fan (moved)
G1 X200 F12000
G4 S0
G1 X250 F12000
G1 X256.65 F1000 ;Change this line (1 of 2)
G4 S2;wait for fan to stop (Added. Adjust if needed)
G92 E0
G1 E0.8 F2100 ;issue
G92 E0
G1 E40 F200 ;1st purge
M106 S255 ;blob cooling
G4 S12 ;blob cooling
G92 E0
G1 E-0.8 F2100
G1 X240 F12000
G1 X256.65 F3000 ;Change this line (2 of 2)
G1 X240 F12000
G4 S0.1 ;synchronous command
M907 X300
;**End purge test**

@bigbrain3d

by tac you mean thumbtack or the cut washer? im not seeing a goove in the thumbtack

@bigbrain3d

using the modified gcode and turning the washer slightly i was able to get 6-7 successful ejections followed by 3 failed ejections. 

@mike-herman

Doh! Sorry yes I meant washer 😉

Well that's an improvement. Is the fan completely off when the each successive blob starts being extruded?

@bigbrain3d

it finishes spinning down shortly after it begins extruding the next blob

@mike-herman

You might try adding 1 second to the G4 waiting command.

If that doesn't do the trick then another video may help me think of the next thing to try 🙂

@bigbrain3d

I added an additional second but it didnt appear to help, added some more on top of that but same thing. Here is a new video, as soon as i stopped the video the blob it was working on failed to eject.

https://www.youtube.com/watch?v=gghHJuGsbdw

Looks like the issue is still the same.

Try this:

;**Begin purge test**
G28 X
M907 X450
G1 X200 F12000
G1 X200 F12000
G4 S0
G1 X250 F12000
G1 X256.65 F1000 ;Change this line (1 of 2)
G4 S2;wait for fan to stop (Added. Adjust if needed)
G92 E0
G1 E0.8 F2100 ;issue
G92 E0
G1 E40 F200 ;1st purge
M106 S255 ;blob cooling
G4 S12 ;blob cooling

M107 ;turn off fan (moved)

G92 E0
G1 E-0.8 F2100
G1 X240 F12000
G1 X256.65 F3000 ;Change this line (2 of 2)
G1 X240 F12000
G4 S0.1 ;synchronous command
M907 X300
;**End purge test**

@bigbrain3d

getting closer! This time i got 20 or so before it failed to eject one

I just did a test on my printer with that exact code and was able to eject 200 without fail. Something must still be off a little. There is obviously some difference.... we will find it!!

Another vid would be great!