Hexagon Hotend requires much higher temperature for PLA?

General LulzBot TAZ
21

We did some further investigation today. After removing the thermistor we found that the PTFE insulation on one of the leads was pulled back, leaving the wire exposed. Slid the insulation back into place and it is now extruding PLA happily at 205C.

22

Sounds good. Gkad you got it sorted out.

23

I just started having this issue today. I thought it was the temperature at first, but I don’t think that is the case.

I tried to calibrate the extrusion per the directions here: https://ohai-kit.alephobjects.com/project/extruder_calibration/

I only extruded around 50mm when I set it to extrude 100mm. The extrusion is coming out fine, just not as fast as the software thinks is happening. I haven’t messed with any of the settings, so I’m confused what else I should be checking. Any ideas?

24

Strangely, i talked with Lulzbot people and they ask me to tighten the spring screws so tight that it almost kisses the 3D printed filament clamp. I did it and it worked! I set the temperature to be 10 degrees higher than budaschnozzle as instructed in TAZ 5 website for hex hotend.

I guess T morris 9 is right about the temperature, there might be some problem with the heating element in hotend in Hex extruder. But tighten it all the way down seems does the trick.

25

ryankivi, if your extruder was calibrated properly and working properly before with the same filament and then started “short extruding” by this large amount out of the blue, there are several causes and they are all mechanical. I would have checked them in this order:

  1. Build up of filament dust/particulates on the cog in the extruder. This is easy to check/see by removing the filament and looking at the cog to see if the teeth are filled with plastic. If so, you should remove the head assembly and use tooth picks or a fine wire to clean each and every groove. It only takes a few minutes. This is by far the #1 reason for what you observed.
  2. Clamping pressure as per the Support suggestion. The reason this might work as a first step is that it is overcoming the filled in teeth on the cog, but it is a bandaid if #1 is the root cause. Sometimes when you change filaments the spring tensioner does not position quite right or maybe the screws got loosened up a bit - especially if you loosen them during the filament change.
  3. A loose set screw on the cog or gear, allowing one of these to slip. The set screws on the cog do require periodic checking and tightening. The first time I do it, I add a little LockTite and never have the problem again. If I had a dollar for every person I’ve helped diagnose a loose set screw with, I’d have $132.00!
  4. Some form of restriction in the filament path - hanging up on the spool arm, a kink in the filament binding somewhere etc. This usually appears as an erratic issue and not a consistent issue.

Cheers,
Michael