Quote Originally Posted by uncle_bob View Post
Hi

Unless you have a really rotten hot end, there is no such thing as feeding to slowly. The extruder and hot end should be able to sit of hours with nothing moving through the system. If you have a really rotten hot end .... it's time to replace it. Simple check: The top of the hot end (where the filament feeds in) should be no more than warm to the touch when in operation. If you can't keep a finger on the top end of it for the count of five, it is to hot.

The simple check is still to tell the extruder to feed filament at the max speed setting. If that feeds fine for foot after foot of filament, the problem lies somewhere else. If it jams, swap out the filament and see if a different brand does the same thing. If two or three brands all do the same thing, your hot end thermistor may giving you bum data or your temperatures are simply set to low.

Bob
By "top of the hot end" are you referring to the top of the aluminum cooling block, or the top of the entire extruder block?
If it's the former, then there's a problem with my printer's insulation from the hot end to the cooling block. The cooling block gets real hot while printing, so much so that I can hardly touch it for more than a second or two. I kept lowering my print temperature until I reached a point where the prints were still jamming and the amount that did print was horribly de-laminated. I can't print any colder.
I'm worried that the heat is traveling up into the aluminum cooling block and softening the PLA thus allowing it to warp in the extruder.