Extrusion Stops

I will try that out once I put my printer back together and let you know - thanks for all the suggestions.

 

By the way - my extruder keeps temps at all fan speeds, so I think that's not the problem. Might just be temp.

 

You might want to consider adding a fan duct to concentrate the airflow on the print and not on the heater block. My E3D fan only points just below the heater block and I see no temperature change even on bridging fan speeds.

Another option that I saw someone mention here is to insulate at least the fan side of the heater block with some Ultra Copper RTV http://www.amazon.com/Permatex-81878-Maximum-Temperature-Silicone/dp/B0002UEOPA or something like it. If you already have Kapton tape on it I'm not sure how well it will stick and you should experiment. Take your time in applying it because it can make a mess.

 

Thanks for the suggestion SteveC. My E3d should of arrived when I get back home so I am probably not going to mess with the stock end any further. I am hoping I will not see the same fluctuation with that.

 

With the newer Jhead, many of us have been experiencing issues with melted filament storing up between the heating block and the PTFE tube. Check out this thread here: http://forums.robo3dprinter.com/index.php?threads/filament-not-feeding-through-hot-end-fixed.2348/

I was having similar issues as you, where one print would be fine, but I would have to remove filament before each next print because it was jamming up. I took the head apart and sure enough there was a plug of built up ABS in there. Just do as the OP in the above post did and move your PTFE tube closer to the heating block and I bet all your problems will be solved.

 

if the ptfe tube is not close enough to the hot end.... rather than move it closer...... Probably is a good idea to replace that ptfe tube with a longer length so it doesn't move back to its original location. I dont have one of these to know if that's possible but it will prevent future problems.

I asked a while ago what hot end this was.... and no one knew or just didn't bother to reply. Just that it ...."came with the robo". Problem is that when china guys reproduce something its not always to spec.

 

It's called the J-head hot end from hotends.com IIRC.

When you push the PTFE tube down, just tighten down the open hex nut that is on top of it. That'll keep it nice and snug.

 

i really doubt that's a genuine j-head from hotends.com (the original creators of the jhead hotend) because the robo printer is manufactured in china. Just because it looks like their j-head doesn't mean it is. there are a lot of clones out there and the clones are the ones that have problems. They dont manufacture them to the same spec. I've never had an issue with a j-head from hotends.com

where did you get this information? or was it just an assumption.?

 

Gotcha. I have read on here before that it was called a "J head" and that the design is continually updated, which has been the case with hotends.com's version as well so I had assumed they meant the same thing. It is entirely probable that ours is a knock off, although I would not be surprised if their spare parts fit our hot ends, they looked pretty similar last I checked.

 

Ours is almost certainly a knock-off - easy way to tell is that there are 4 rows of cutouts in the PEEK for heat dissipation - current spec is 5 sets.

 

Issue fixed (maybe). Ordered some ColorFabb PLA/PHA from PrintedSolid and all problems went away- ~24 hours printing and no jams, clogs, etc. Tried 4 different colors with same results.

Maybe bad-spec filament in the Robo reel I got, or maybe it needs higher temps? either way, it is ColorFabb for me from here on out. Frustration not worth the price savings.

 

I had exactly the same experience. White seemed to work OK at 205/195, but then jammed up in a big way.