Almost always missing layers / underextruding

[mr.-waldorf 0]

 

In short,

After changing thehttp://umforum.ultimaker.com/index.php?/topic/4319-prints-quality-improvements/page-2 and use a new filament spool, already got 4 successful extrusion tests at 10mm3/s

 

 

 

Hey Schafe! 0/10 Blarps to gr5

 

[mr.-waldorf 0]

So... What do you guys think we should do? Lets exchange some thoughts here...

Should we get a way to straightening the filament or should we adjust the UM2 to be able to deal better with bended filament?

Its easy to make an external device to straighten the filament before the feeder material, this could be done with two heated wheels or rolls and the filament would pass between them.

Another thought... what about a teflon coupler with the inside hole in cone shape, like a funnel?

Any other ideias to deal with bended filament on a UM2?

I forgot to mention the easy and lazy way... just buy unspooled filament

 

[mr.-waldorf 0]

I was planning do the same and this post saved me some € on a new nozzle. !

 

Oh... I was so wrong....

 

18mm^3/sec at 230C

 

Now I really have to do the same and spend some bucks

 

[gr5 2,173]

Any other ideias to deal with bended filament on a UM2?

 

Yes. Drill out that teflon piece a little bigger. I think it's inside diameter is around 3mm (I didn't measure it). Drilling to 3.2mm may fix all of these underextrusion issues if they are caused by overly bent filament due to diameter of winding on the spindle.

 

[Nicolinux 288]

I'd be cautious with drilling the teflon piece. I did file away just a tiny bit on my old one and it changed nothing. I have the feeling it made it worse because now the filament would have more space to expand in the cavity where the nozzle and the teflon piece meets.

However, if your teflon piece is less than say 3.1mm, then drilling would be in order.

 

[schafe 3]

I thought I was on to something.

You can see several spots where the extruder skipped on the first layer. Note they are bigger and more frequent the further the print head got from the home position. I watched layers 2 and 3 print 100% without error. I have not been watching, but for the last hour I have not heard any skips and everything looks great when I stop by for a look. Just another confusing observation I guess. First layer printed at .8mm3/sec the rest at 2mm3/sec at 240C and 100% flow.

I don't blame the folks at Ultimaker for being silent on this issue. Admiting there is a problem with their new baby would hurt sales and give competitors an advantage. Maybe they have and I just missed it. It would just be really reassuring to know there are people working on this issue whose paychecks and reputation depended on a solution.

 

[ian 32]

the community is working hard to solve this issue !! :-)

http://umforum.ultimaker.com/index.php?/topic/4393-ultimaker2-feeder-system-improvements-and-ideas/page-9&do=findComment&comment=38981

Guys before your drill more holes and disassemble more hotends and feeder system.. why not read the above tread.. then you have more background info on what problems are lurking at the back of the ultimaker2... and also what might or is causing your problems mentioned in this tread !

Ian :-)

 

[Nicolinux 288]

Hey Ian,

no offense but I still doubt that it is the feeder. The stock extruder can pull filament hard enough. And the fact that I've never experienced a clogged nozzle on the UM2 also dismisses the theory that parts of the extruder case come loose and get stuck into the nozzle.

But your feeder looks very sexy. The filament straightening part and the fact that you can pull out those thin filament strands are very cool. Will print it for sure (when I have my printer back that is).

 

[ian 32]

zero offense taking... im just saying the more and more i study the feeder system and how the existing design so badly handles filament, I would look at that bad boy for many peoples problems..

Of course there could be simply a fault with your printer from one single faulty part or wrongly assembled.. who knows ?

Have a lovely day !!

Ian :-)

 

[mr.-waldorf 0]

Hi Ian,

I am following the feeder material tread and your work very closely

Can you test your new material feeder with a almost empty spool? (more bended filament)

Thanks

Nuno

 

[ian 32]

Hi Ian,

I am following the feeder material tread and your work very closely

Can you test your new material feeder with a almost empty spool? (more bended filament)

Thanks

Nuno

 

Thats a very good idea !!!

I have some at home I can test tonight !!!!

Ian :-)

 

[mr.-waldorf 0]

Hi Ian,

I am following the feeder material tread and your work very closely

Can you test your new material feeder with a almost empty spool? (more bended filament)

Thanks

Nuno

 

 

Thats a very good idea !!!

I have some at home I can test tonight !!!!

Ian :smile:

 

Thanks Ian

Hey ULTIMAKER TEAM !! You should send Ian a new filament spool, he certainly deserves. The work he has done, the commitment and the excellent "marketing" to the brand Ultimaker should be compensate...

Cheers

 

[schafe 3]

Finished reading the topic suggested by Ian. I had no idea that was going on. Good stuff, talented people. I'll do my best to be quiet and wait patiently.

BTW the print in the photo I included above turned out very nice. .5/10 Blarps.

 

[ritzenthaler-fabrice 0]

 

Hello, look at these photos printed with the same identical pieces paramètres.Pla red innofil 2.85 nozzle 210 degrees speed 75 25mms bed layer 0.2. A very nice, the other unextrusions?

Cordially

 

 

 

[aaronalai 2]

Hey @ritzenthaler can you note a couple of things?

Which item did you print first?

The amount to time that elapsed between prints?

The approximate diameter change of your filament spool, for each print? Was the spool getting low on filament for any of the prints?

The room temperature?

I know you might not be able to recall all the requested information, but any information you provide can help support or discredit some hypotheses that have been generated in the forum.

Thanks

 

[Nicolinux 288]

Wow, not bad. I printed 36 extrusion tests up until now. My aim is 37 and no more

 

[gr5 2,173]

New information. After this test, I'm 90% sure there is no heat related problem with the extruder driver:

http://umforum.ultimaker.com/index.php?/topic/4222-pulling-force-of-um-extruder/?p=39763

 

[braddock 1]

I haven't checked in here for a while, and I've been trying to print something today for the first time in several weeks. Again, plagued by annoying and persistent under extrusion.

 

I haven't read through this monster thread, but, has Ultimaker officially chimed in on this issue yet?

 

[geeks 1]

Indeed, from the middle coil, erratic problems begin.

 

I agree with Ian, that we adjusted the wire before the extruder. I'll see, maybe one day, if I dressed with 3 pulleys to make it right. But already two is not so bad.

 

I expect to see results.

 

[gr5 2,173]

Again, plagued by annoying and persistent under extrusion.

 

Very few people seem to have the problem and the machines at Ultimaker seem fine. If you want to get on the list of people who have problem this is a good thread to check out - I considered adding you to the top post but I would like you to print Illuminarti's test piece first. Here's the other topic:

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

Basically many people have had problems and then "fixed" it but the fixes vary and are so completely different that I'm confused about this whole underextrusion issue. I have had a new hypothesis every week but right now they have all been disproved. I don't even know if the problem that people are still having (only like 3 people by the way) is related to nozzle, or feeder or something else.

Things that seem to be issues:

1) Everytime you change filament on the UM2, it heats much too hot and then retracts with no control and you get long threads and blobs and hot pla in your bowden which are not very noticable yet cause horrible underextrusion issues due to jamming in the bowden. With the UM1 this was obvious and fixed immediately. With the UM2 the underextrusion is "a mystery".

2) The PLA feeds into the feeder at a bad angle. Putting the PLA on the floor helps. Also when you are "near the end" of a spool of filament the tight bend radius seems to be a problem inside the feeder, also inside the bowden and also inside the teflon white piece in the print head.

3) The teflon white piece has been deformed for some people causing it to be VERY tight to pass filament through. This is easily fixed by drilling it out with a 3mm drill bit.

4) Loosening the 4 longs screws on the print head has helped some people. Loosening the screws on the feeder has helped some people because it was keeping the roller arm from moving and not squeezing the filament against the knurled sleeve hard enough.

5) Partially clogged nozzles that look clean yet have some old ABS in there somewhere.

6) The feeder is made of ABS which gets worn down by the PLA. Two issues: pieces of ABS end up in the nozzle, also wear on the feeder can increase the friction. Significantly.

7) The knurled wheel is sometimes not far enough in. There is a square nut used in the case of the UM2 that can push on the feeder motor away from the back wall of the UM causing the feeder motor shaft to be tilted significantly which can evidently even cause a spiral feeder pattern on the filament as it passes through the bowden.

8) The wear and tear on the feeder *might* be causing the ball bearing to get stuck between the black pieces of the feeder due to pieces of abs clogging things up in there.

There's more. There's theories about heat causing current issues on the motor that I don't believe anymore. I forget what else. Here's my absolute favorite fix so far:

http://umforum.ultimaker.com/index.php?/topic/4145-small-question-about-material-feeder/?p=35649

 

edit: 9) If the bowden pulls out a bit of the head then there is an air gap between the end of the bowden and the teflon - PLA can soften and get stuck in that gap preventing the filament from easily going up or down.

 

[illuminarti 18]

Great summary, George, thanks.

 

[braddock 1]

thanks gr5, I've posted my extrusion test results in that thread. Also, your list above doesn't mention the bowden tube pulling out of the hotend? this is definitely an issue when combined with retraction.

 

 

[gr5 2,173]

Also, your list above doesn't mention the bowden tube pulling out of the hotend? this is definitely an issue when combined with retraction.

 

I added the only issue I know about just now as #9.

I have done a kilometer of retraction in a single (long!) print and never had issues with retraction - it worked great.

 

[mr.-waldorf 0]

Hi George,

Very nice job indeed, awesome synopsis

Congratulations.

 

[mostlyatomicbob 34]

Good work George.

My problems appear solved.

see here:

http://umforum.ultimaker.com/index.php?/topic/4586-can-your-um2-printer-achieve-10mm3s-test-it-here/page-4&do=findComment&comment=39894