Print head oozes plastic from all over

[thereza 0]

I followed the build instructions exactly, and even have the <1mm gap between the aluminum plate and the wood piece which should mean that everything has been correctly tightened on the print head, but I'm oozing a ton of plastic from all over, including both the top and bottom of the print head, causing some grief i the build process and dropplets of plastic fall down. I've taken some pictures and posted them here:

https://plus.google.com/photos/11291268 ... 5298877777

Here's an example of the ooze from the bottom.. It also oozes from above the heating block..

Any suggestions would be appreciated.

Thanks,

reza

[IRobertI 520]

I don't know if this is the correct way to solve it but it worked for me when I had that problem in the start. Heat the block up to printing temperature and then tighten the block against the peek and the printhead against the block by a small amount, say 1/8th of a turn. Then try to print and see if it still oozes. If it does, tighten another 1/8 of a turn and try again. Now I'm sure one could tighten it up faster than that but I was in no rush and didn't want to risk breaking the brass pipe. Since I did that I've been printing for hours without any sign of leakage.

[owen 19]

Hi

Here's how I do it if everything is already assembled, others may differ.

1 Turn the UM heater on to just enough heat to make any plastic in the threads soft.

2 Loosen off the 4 main bolts so you can unscrew the peek block.

3 Tighten 2 - 6mm nuts onto the brass tube on the opposite end of the nozzle

4 Turn the top nut clockwise while holding the heater block so the brass tube turns down through the heater block a few turns.

3 Screw the nozzle onto the brass tube firm using PTFE tape while using the top nut to hold the brass tube still.

4 Turn the nozzle while holding the heater block so the that the brass tube screws back up through the aluminum block all the way till the top flat part of the nozzle tightens up against the bottom of the aluminum block.

5 Remove the top nut and then the bottom nut while holding the block.

6 Tighten down the Peek piece onto the brass tube through the aluminum plate till it meets up against the top of the aluminum block. Make sure you are holding the nozzle with a spanner etc. so that the brass tube does not wind back through the aluminum block and create a gap between the aluminum block and nozzle.

7 Tighten up the the four screws from the top getting the bowden tube end right (See instruction in Wiki) while preferably holding the heater block in the orientation you want it to end up, usually running long wise from front to back with the thermocouple hole on the correct side.

Notes

Always hold the heater block when necessary to not put strain on the wires.

You may use a bit of heat transfer compound, like that used on CPU's in computers, between metal parts to aid in heat transfer but not necessary.

You shouldn't need tape between the brass tube and aluminum block but could use a bit if it helps in tightening things up. The real pressure is between the brass tube and nozzle and this is the one to get right.

As the brass tube becomes older it gets softer and is more breakable due to over tightening.

All the best

[micha 0]

I made the same mistake and followed the instructions word by word.

The thing is... sometimes it's worth using the own brain.

In the instructions, they miss, that you should add some teflon tape to the thread, that goes into the nozzle, as well. (Or I didn't find that part :mrgreen: )

I heated up everything to 200°C, about 10minutes.

Reversed the filament until I saw the end in the tube.

Unscrewed the four long screws, that hold the big aluminum part, a bit.

Unscrewed the nozzle and the brass tube.

Burnt my fingers.

Held the nozzle with some plyers and heated it with a heatgun and blew the plastic out with compressed air.... about 20times, until it was clean.

Same thing with the brass tube, heatgun and a towel... heatgun, towel....10-20times, until the thread was clean.

Tested both ends, if they are clean enough to be screwed into the thread.

Wrapped both ends with two turns of teflon tape.

Screwed the nozzle on. A small screwdriver sticked into the tube, holding within the fragments of filament, that are left in the tube, helps a lot.

Screwed the nozzle with the tube through the heaterblock, into the peek.

Fine printing.

Hope it helps

Micha

[thereza 0]

Thanks for all the great suggestions, I'll go try them out tonight.

Reza

[Daid 306]

Note, if the instructions are incomplete, you can update them and help the next people