Extruder stops extruding after a while

I start a print on my reprap and the first couple layers print perfectly print great , and eventually my extruder keeps trying to extrude and i cant unless i give the plastic a push.

Thanks,
Daniel

Do you have a fan on it. Sounds like the temp is moving into the cold and making the plastic harder to move. Another option is that the pressure against the stepper drive is not hard enough and it slips and lastly you might not be having enough current going to the extruder stepper to move the filament when it starts to get tough to move.

Could be several things. If the extruder continues to move, but fails to extrude its probably one of the following.

1) the pinch wheel has stripped the plastic. Try reducing the pinch pressure slightly.

2) Temperature has gone down. It may have switched off. There is an over temperature setting in the firmware that switches off the extruder. I have had reading spikes and in the end have disabled this feature.

Ok, ill give it a try, Thanks for your help