Oozing out filament before printing starts

[3dnerd 6]

Hi,

I use my UM2 with the latest version of Cura (15.02.1).

When the printer has finished heating up it starts to ooze out some filament in the front left corner of the printbed. After around 10 seconds the head moves to the start position and starts printing. During this movement the filament gets dragged over the printbed.

Sometimes the filament (coming from the 10 seconds oozing) sticks on the nozzle like a woollen ball and gets dragged along the printing prozess and destroys already printed paths, almost on first layer.

The oozing itself is not the problem, since it makes sure material comes out the nozzle. But the dragged filament over the glass plate and also the woollen ball is problematic!

I wish to have an additional feature so that the oozing stops after 10 seconds. Then a 'Continue' message will appear on LCD screen.

Then the user has enough time to clean the nozzle before the printing really starts. Then he can continue by pressing the wheel.

I tried to 'Pause' the print but the pause is delayed so the printhead is already somewhere in the middle of the printbed where it is difficult to clean since it is also very close to the glass surface.

How do you deal with that?

Is there any way to get rid if that?

 

 

[DidierKlein 729]

What i usually do is grab the filament that is extruded (with fingers (beware of heat) or pliers). And it's all good.

If you would pause after priming it could introducing some clogs in the nozzle.

 

[dirkdirk 5]

You can try to modify the start gcode. Insert a M0 after Priming.

Make sure to use a long skirt/brim/raft so that it will not clog.

[skint 61]

+1 for Didier

I watch the beginning of every print, and grabbing this filament is the first step I grab the filament and gently pull it over the front of the bed making sure there is none of that ugly "woollen ball " on the nozzle.

 

[yellowshark 153]

No idea if there is a workaround, I just "suffer" it. I have a dedicated screwdriver. My setup is that as the oozing starts, the print bed is raising and the nozzle starts to move to its print start position. So I just place the screwdriver beside the hanging thread of filament and move it to one side as the print bed nears the top of its travel, so that the thread lays down flat on the bed, out of the way and then follow the nozzle with the screwdriver in case the filament does not immediately adhere to the bed and just help it on its way with the screwdriver. If any does stick to the nozzle then I just push it off with the screwdriver.

I do find the screwdriver to be probably the most important piece of equipment after the nozzle

I always print either a skirt or a brim so the oozing filament thing is never a problem with my models.

 

[gr5 2,172]

Use your fingers you cowards!

When I start a print I go into a zen trance (like in an elevator) until I hear the bed come up and I instantly come alert and get my hand close to the nozzle to grab the initial "priming" (like priming a pump). As the head moves towards the print I pull slowly sideways outward from the printer and I speed up faster and farther until the thread is so thin it's like a delicate hair than won't interfere with anything as it starts the skirt or brim.

 

[gr5 2,172]

Other slicers have a feature better than Cura - they do a prime (just like um2) and *then* do a wipe along the edge of the surface of the print bed - far from the print (not sure what they do if the print reaches all the way to the edge). This works very well. Then they move the bed away from the nozzle a bit and zip over to the start of the skirt/brim.

 

[skint 61]

I have seen printers with a small wire brush near the bed, and prior to every print the nozzle gets pushed through the wire brush, both cleaning off the pre-print material but also keeping the nozzle head nice and shiny n clean

 

[3dnerd 6]

Thanks for the replies,

I am reassured that others have similar problems ;-).

@dirkdirk: What does the M0 do and how do I find the correct line after priming in the gcode to insert the M0?

Is there also a gcode command which waits until I press the wheel?

 

BTW, the Robox printer (www.cel-robox.com) has a small rubber plane where the nozzles moves over.

This wipes away any left filament from the starting oozing.

Something like this would be great for next UM3 ;-)

 

 

[yellowshark 153]

LOL George my finger does not reach as far as the screwdriver, unless I am printing something in the front qtr of the bed, which would be unusual for me. Yup Slic3r wipes the nozzle at my wipe station in the SW corner - so long since I have used that slicer though I cannot recall if it helps.