Wades extruder problems. too little PLA gets extruded.

hi.
I have great trouble with my extruder .
It seems to extrude nice and clean, I can run lots of tests , like thin wall test. and is tight, and have what seems like more then enough force to feed the hotend.

Then during prints - it does what seems like it starts to slip or something, and less and less material is extruded (see attachment)

What's causing this ?

Could be nozzle temp dropping. What speed are you running?

do you have retract settings set to low numbers, and what temp are you using. if temp varies a lot consider
using pid algorithm? sprinter firmware supports pid

also have you properly calibrated z height?

run this
[www.thingiverse.com]

do the tower stl file and make sure it turns out ok. also sets calibration above 50mm, it is hard with the normal test calibration to know z calibration because 2 layers is really not enough to test it. also make sure z height is correctly set in sprinter, and to set the limits for speed in firmware to 100mm /minute or 1.6mm/s on z axis until testing is completed. skienforge is terrible at managing z feed rate with skin feature enabled, so disable skin feature, and set limits tab for firmware speed control as well.

what type of wades bolt are you using hobbled or knurled?

you will get it running

Edited 1 time(s). Last edit at 12/29/2011 09:19PM by jamesdanielv.

Hi.
Most is being printed at 5 & 6 mm/s , some (fill) at 10
Z is calibrated, I did previously print the "same" object just fine (then tweaked some size)

I discovered that the thermistor lost connection, may it be I overcooked the filament/causing jam ? - fixed it now and retrying a print.

Where do I suggest that the firmware should have a emergency shutdown if temp falls to "0" ? - with very powerful hotbed and/or nozzle resistor, this simple error could even be dangerous.

in configuration.h
change #define mintemp
to
#define MINTEMP 5 ;// 5 is safe. if temp ever below this at start up heater will never turn on!

nice, thanks - what remains - is to detect if thermistor connection is lost, during print.

If your thermal insulation between the hot end and the cold end is not good, then the PLA might be getting too hot and soft at the pinch wheel causing it to start slipping. This is consistent with your print that starts out fine but gets worse later on. You can minimize this by blowing air at the thermal insulation or providing a heat sink like a plate of aluminum between the insulator and the cold end. You can use a small fan or an aquarium air pump to blow air.

I have a fan that blows on the cold end's heatsink - and *only* that.

still - when I insert filament - it's easily pushed down to the hotend (extruding), after a pause, there's much more resistance. (more force is needed to extrude.)

Would you suggest a fan should blow on both the heatsink *and* the hotend ? (and as little as possible on the extruded material ?)

Edited 1 time(s). Last edit at 01/01/2012 02:22PM by Andke.

you mean like :[www.makergear.com] ?
would that even fit my "wades geared extruder ?"