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somerwil

Extruder jamming

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Hi guys,

I'm frequently jamming my extruder. This problem occurs mainly after I tried to extrude material at too low temperatures (ie Netfabb standard settings). The nozzle itself is fine and is not jammed, my material gets jammed inside the PEEK insulator. The feed mechanism on the outside works perfectly and has enough force to push the material into the tube

I think my tube is not getting into the PEEK part far enough. On the instruction wiki it says the Bowden tube needs to get out of the bottom wood part for about 8mm. I can do that but when I place the PEEK on top of it, the cable doesn't slide all this 8mm into the PEEK. When I complete the assembly, the cable goes into the PEEK for approx. 5mm and pushes the tube back for some 3mm. I can imagine my cable is not directly connected to the brass piece of the hot end and thus creating a unwanted buffer.

Any suggestions?

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I'm frequently jamming my extruder. This problem occurs mainly after I tried to extrude material at too low temperatures (ie Netfabb standard settings). The nozzle itself is fine and is not jammed, my material gets jammed inside the PEEK insulator. The feed mechanism on the outside works perfectly and has enough force to push the material into the tube

I think my tube is not getting into the PEEK part far enough. On the instruction wiki it says the Bowden tube needs to get out of the bottom wood part for about 8mm. I can do that but when I place the PEEK on top of it, the cable doesn't slide all this 8mm into the PEEK. When I complete the assembly, the cable goes into the PEEK for approx. 5mm and pushes the tube back for some 3mm. I can imagine my cable is not directly connected to the brass piece of the hot end and thus creating a unwanted buffer.

There are a couple of things inside the hot end that needs to be solid and never move: one is the PTFT tube inside the PEEK, and the PTFT retainer ring/clip above (if the ring/clip does not support the bowden tube anymore, print some reinforcement:

http://www.thingiverse.com/thing:11864

).

The PTFT needs to make a solid flat connection to the brass tube inside the PEEK:

IMG_4072.jpg

As you can see it is very difficult to get a perfect perpendicular cut/connection, and if the PTFT isn't pressed hard enough against the brass, plastic will leak, and the problems start.

you can solve this by drilling out some of the bowden with a 4.5mm drill (by hand), not much deeper than 0.5mm (depending on how far the brass tube extends out of the PEEK):

IMG_4073.jpg

IMG_4076.jpg

(In this example I drilled a bit too deep, but you can shave off some of the PTFT to lower the depth of the bevel.)

Now the Brass tube can slide into the PTFT ever so slightly (especially if your brass tube thread is turned down a bit), making a much better seal:

IMG_4074.jpg

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Fantastic! Thanks for the tip and included pictures. Did you make these yesterday or are they on the internet? They should make it into the wiki/ troubleshooting.

I'll try this out tonight and let you know if it worked for me.

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Fantastic! Thanks for the tip and included pictures. Did you make these yesterday or are they on the internet? They should make it into the wiki/ troubleshooting

I just shot them this afternoon, specifically for this purpose... if they want to migrate into the wiki, fine by me.

Let us know if it helps.

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