200% infill goobers

[JFettig]

I've been struggling with goobers left behind by huge amounts of pressure build up inside the hot end due to 200% infill, regular retractions around borders don't make any strings, but after infill, it retracts, travels across an open boundary and leaves behind a large string, often times 1/2-1" long where it wouldn't normally do that.

Is anyone else seeing this? It doesn't string or blob otherwise, retractions work great on borders, just not the infill. My bowden tubes are 1 meter long, It depends a little on the material, how bad these are, but printing with PETG(just started today) seems to be worse than ABS. It looks as bad as when I was accidentally running 3mm retractions. Retraction speed doesn't seem to change it - however I haven't gone under 40mm/s yet.


Strings are worse on the back side, just not a good shot while printing.

Ideas?

[JFettig]

I believe I fixed my problem - I went from 240c to 250c, the goobers went away but it was stringy, now up to 260c and its not even stringing. It went from that white color to almost clear!

[dsegel]

What is 200% infill? How is that possible?

[JFettig]

Infill extrusion width: http://forum.simplify3d.com/viewtopic.p ... 7563#p7563

[jimc]

haha ahh yes. petg is completely different animal. its great stuff to print with BUT its not forgiving if your settings are just slightly off. it has a very narrow window. it may take some time and testing to get good settings nailed down but when you do your good to go. i actually found 200% to be too much with petg. its great for abs and others. my infill width for petg is 150%.

[dsegel]

Infill extrusion width: http://forum.simplify3d.com/viewtopic.p ... 7563#p7563

Thanks, I thought you were referring to Infill Percentage.

[JFettig]

So I jumped the gun, its still doing it. The last print I canceled 3 times because of it and finally gave up, at the time I was wiping everything - which I'd prefer not to. It would be interesting to have an option to wipe on infill.

[jimc]

petg is very sticky when its hot. it likes to collect on the nozzle in a big lump then at some point release. i will tell you that with petg if you have accumulation on the nozzle it is from one thing....overextrusion. where as with abs or other plastics any extra material just bulges out and the part gets bigger or the layer is higher. petg doesnt do this. any extra material collects on your nozzle in lumps. i found 200% for infill to be overkill. i run 140-150. i found that to be just right. the first layer cannot be printed low or squished onto the bed either.

[JFettig]

I will give that a shot, I have 3 or 4 burnt chunks on each of the prints I ran. The problem was I calibrated Z at 235C and then printed at 260, it squished into the bed and accumulated. Not good.

[jimc]

first layer is super critical with pet. it needs to go down perfect. what brand pet are your using?