Atomic Method - Is this to be expected, or an issue?

[closedcircuit 1]

There is always a bulge about 2cm up from the tip of the filament when I perform the Atomic method on my UM2. See picture enclosed. Is this to be expected?

Thanks!!!

Phil

 

[Blizz 53]

Not entirely sure but it seems to indicate some space between your teflon and the nozzle. In any case, I don't have this when I do an atomic.

 

[closedcircuit 1]

Thanks for the quick reply.

Would anyone know how to fix it?

 

[gr5 2,170]

You can take it out and file it flat and drill it out.

You can ask for a new one from UM.

You can ignore it.

It can cause underextrusion if it is too severe. You can test how well your printiner is doing. You need to be able to print at least 5mm^3/sec of PLA at 230C:

http://umforum.ultimaker.com/index.php?/topic/4586-can-your-um2-printer-achieve-10mm3s-test-it-here/

If you can't hit 5mm I would try to fix it. This part deforms under temps over 240C. Very gradually over many days. UM has a newer one that is a little more resistant to deformation that started shipping this past Sprint I believe.

Also I think you should do the Atomic Pull at a lower temperature than whatever you have been doing. Maybe another 3C cooler until it comes out a little less stretched.

And keep doing it until all that black gunk is gone.

 

[closedcircuit 1]

Thanks for your reply. Your help, as always, is very much appreciated.

I think that I will ask for a new one from UM as I do have underextrusion (even at high temp.). I'll keep on doing the Atomic Pull. Reckon that I still have some ABS from a long time ago coming out (hence the higher temp...).

 

[Dim3nsioneer 557]

I usually pull it at 80°C on the UM2. Like that I get the most of the gunk out.

@gr5: Do you know the exact material which is used for the new teflon piece? I only now that it is PTFE which has glass fibres in it... the question is, how much? 15%? More?

 

[gr5 2,170]

1) When you switch from ABS to PLA you can do an Atomic pull (or "cold pull") also. More like 130C. This gets it all out. I do the pull method on my UM2 now on every filament change - through the feeder (I don't remove the bowden anymore). The feeder doesn't offer much resistance. I insert filament this way also (I don't use the menu - just shove it in).

2) 240C should be hot enough to get ABS out. Any hotter and it won't help - it will bake the ABS into some other chemical.

3) Everyone gets underextrusion at some speed and temp. But if you are getting it at 5 cubic mm at 230C then your machine is working reasonably well. It's like saying "I get short of breath when I run". That means nothing unless you qualify it. Can you do the 100 meter in 1 minute? 10 seconds? Maybe that's normal/expected. Maybe it isn't.

 

[closedcircuit 1]

@Dim3nsioneer: Thanks a lot. I'll try 80 (was at 90 and 130).

@GR5: I already do 1) and 2). With regard to 3) - It's sporadic. Sometime the test cylinder prints well up-to 10mm3/s, sometime I can't get 4mm3/s. This is confirmed by the fact that I usually experience problems on longer prints (so there seems to be random variances involved). Anyway, I've followed one of our suggestions and contacted UM.

 

[illuminarti 18]

Can you post a photo of your head from the front, showing the position of the teflon coupler?

Are you doing the cold pull without the bowden in place?

I suspect the bulge is just the plastic softening into the area at the top of the teflon part, where the bowden normally goes.

This may be because you teflon coupler is getting extra hot - or perhaps just a function of how long you leave it sitting hot when cleaning. Is the fan on the back of the print head running all the time?

 

[closedcircuit 1]

@Illuminarti: Thanks. A picture is enclosed below:

 

>>>Are you doing the cold pull without the bowden in place?

Yes. I must add that I am very careful to reinsert the bowden all the way down before securing it.

>>>or perhaps just a function of how long you leave it sitting hot when cleaning.

Not that long. I normally wait until the head is at 230 or 240, insert the filament and push gently so that about 5cm of thread gets extruded and then immediately turn the temp. down to 130 or 90.

 

[gr5 2,170]

The atomic method requires a warm/extrusion temp and a cold, pull temp. 90C is about right for the cold temp for me. 180C is plenty hot for the hot temp. No need to go any hotter than 180C when doing atomic method. For PLA anyway - not so sure with ABS.

Atomic method is good at getting dust and dirt out but not necessarily ABS. For ABS baked into gunk it might be tough to get it all out.

You didn't say how old your printer is but a new teflon piece would be smart. I don't know how much glass is in the new teflon isolators.

 

[gr5 2,170]

closedCircuit - you didn't mention about your 3rd fan. Please test that this is working as your symptoms match those of people with broken 3rd fan.

 

[closedcircuit 1]

@GR5: Apologies for not having replied sooner. The printer is five months old. The good news is that UM have already been in touch (great!) and said that they would send a new part.

The third fan is ok.

Thanks again for your help!