spewing filament at start

[aratome 0]

I've got a brand new Ultimaker2. At the start of each print, after the bed comes up but before the print head leaves the front left corner, the nozzle extrudes several inches of filament, which ends up in a pile and can stick to the head. I can whisk the spewing filamant away with a piece of paper and it prints pretty well, but how can I prevent this behavior?

I'm using PLA

I've updated the firmware over the USB cable

Thanks for any help!

 

[illuminarti 18]

You can't really prevent it, and you don't want to. It does this pre-print purge and prime to clean out any filament that has sat heated for a while, and so might have degraded a bit, and also to ensure that the head is fully pressurized with plastic so that the print starts correctly. Simply get a pair of needle-nosed tweezers, and pull the pile of filament away from the head before the print starts.

 

[aratome 0]

OK, good to know this is normal behavior. Thanks for the input.

 

[merardo 0]

The pre-pint purge is normal;

Actually I am having the problem that the pre-print purge doesn’t occur, when this happens the printer starts but doesn’t extrude material, or extrudes a very small amount like dots;

 

[illuminarti 18]

What program are you using for slicing, Merardo? If it's Cura, you'll need to make sure that you tell it to generate 'Ultigcode', not normal Marlin/Reprap gcode.

If you are using another slicer, you'll need to adjust the starting gcode to advance the filament at least 20mm before printing, to counteract the automatic 20mm retract at the end of the print, and then an additional 8mm or so to actually flush plastic through. The first movement you can do at say 5mm/s (300mm/min) since the filament shouldn't actually be extruding, just moving into the empty head. The second part you should do at 1mm/sec (60mm/min) to simulate a normal fast-ish print speed.

Also, make sure you have the firmware installed from Cura 14.07 (check the version in Maintenance -> Advanced -> Version, on the printer), as earlier firmwares had some issues with grinding away the filament by doing those purges too fast.