Underextrusion / Extruder jamming ... slic3r question

Eriobis

Hello,

        This is my first post here, I hope I am at the right place since the question is about slic3r and repetier too.

I can't get a good print when I try to print under 0.3mm on a Afinibot Prusa I3.

I can hear the "clunk clunk" sound from the extruder, so I am guessing there too much backpressure in the nozzle. ( The drive voltage/current has been tested and the extruder springload has been tested too )but I can see the motor not having enough tork when the nozzle isn't free.

So, my question about is what speed should I use to free the nozzle end to have a good print ?? Or should I raize the Z a little bit ?

Maybe I am printing too slow or too fast, I'm not sure about that.

Question about repetier : How can I increase the z axis while printing ?? I want to try something to get rid of that problem.

Bonus question : Glass makes a better finish but is harder to get a good first layer, should I go back to blue tape ?

Thanks guys !

Had to stop the print because it would have been too weak. ( this is a wall hook )

p.s. i'm using Repetier Host 1.6.1 with Slic3r 1.2.9

Repetier

You need a short melting zone if your lacking torque. Especially if the beginning works and later it starts to block it is normally heating up extruder and melt zone walking up that blocks the extruder. Here you can cool the hot-end better if it is a full metal hotend or print at lower temperature so cooling still works after longer heatup.

It can also be changed with different filament types as well. Low melting PLA can be quite difficult as it can move up more easily. You could try Polymaker filament, which seems to print pretty well. That's also why ABS comes out so easy on most extruders, but it warps, stinks and is not healthy with toxic fumes, so better find the sweet spot of temperature and speed that works for your extruder. Try print 30-50mm/s and lower temp. in 5°C steps until it refuses to print or stops hanging.

BuildTak also gives a nice finish and holds most filament types pretty good. It's not as smooth as glass but has a regular coarse pattern much like blue tape, which also works.