Material flow challenges?

[friedl_basson 5]

Hi - 

 

Lately I have been facing a challenge with what seems to be, under-extrusion. From what I can recall, it started after I have been printing with TPE for a while and had to open the extrude to remove stuck filament. I have attached a photo of my current print.  It is a large flat part so the gaps between the print lines are quite obvious from layer 2 onwards.  My current settings are:

 

• Printer: UM2+
• Filament: PLA (Spidermaker, Ultimaker or Fiberlogy)
• Print temperature: 210
• Bed: 60C
• Extrusion 100% (as per Ultimaker PLA profile) 
• Fan Speed: 100% (as per Ultimaker PLA profile)
• Layer hight: 0.15mm
• Speed: 60mm/s
• First layer: Concentric
• following layers: Lines

 

My current work-around for this problem is pushing print temperature up to 220C and flow rate to 110%.  My concern is just that this has never been necessary before and for the life me me, I cannot figure out what the problem is.  I was hoping to resolve this without having to send the printer to the agents which is 1600km away and I have urgent prototype prints that need to go out.  I cannot afford to be without the printer for two weeks.

 

In the meantime, I purchased a new nozzle, I am hoping this will resolve the problem even though not very hopeful. I am assuming it is not bed levelling as the first layer was perfect, printed with Concentric setting.

 

Would appreciate some help 🙂 

 

Kind Regards

Friedl.

[Torgeir 228]

Hi @friedl_basson,

 

As you have printed for some time with TPE and maybe at some higher print temperature?

Then some under extrusion started.

 

I would check that the feeder is function properly, then that the hot end cooling fan is working and finally the insulation coupler (TFM).

 

If one of those three items fails it will always led to under extrusion of some sort.

 

Good luck

 

Torgeir 

[friedl_basson 5]

Hi @Torgeir -

 

Thank you for your reply.  Just to comment on your questions:

3 hours ago, Torgeir said:

As you have printed for some time with TPE and maybe at some higher print temperature?

 

I printed with Fiberlogy TPE. The printing profile is similar to PLA on Ultimaker printing at ±210C.  Only major difference is retraction is disabled.

 

3 hours ago, Torgeir said:

I would check that the feeder is function properly

 

How can I confirm this?  As I mentioned, when set to 110% flow rate, the large flat print looks good.

 

3 hours ago, Torgeir said:

then that the hot end cooling fan is working

 

This ons is easy enough to conform, Indeed it is working  🙂 

 

3 hours ago, Torgeir said:

and finally the insulation coupler (TFM).

 

This is the one I am scare of even though it is fairly new.  I upgrade to the 2+ using the kit and have printed maybe 3 full spools since then. With the last nozzle change it was more difficult to get tge nozzle in.  I am not sure whether some melted material got in the way.  Maybe best to send the printer to the agents as soon as possible,

 

Many Thanks!

Friedl

[Torgeir 228]

Hi @friedl_basson,

 

Edit: I'll add a little more information to better understanding of the problem, for people in general.

 

I'll think that as the increased feed rate fixed the problem the feeder can be considered OK.

 

Aha, you're using TGE nozzle, is this the steel one? If it is, be aware that this nozzle have less heat transfer properties, so you might print slower in order to avoid under extrusion. Some people use to increase the temperature some, but this can sometimes lead to a problem as the density might change during printing. (Because the temperature will increase when the speed decrease and vice versa.)

 

So if you're using TGE nozzle with PLA it will suffer as this nozzle cannot heat fast enough.

(If, we expect to print with same speed as we used with the original the brass type of nozzle.)

 

For changing the TFM coupler, I'll understand your fear here, as I've never seen any good procedure for tightening the nut that's "compressing" the coupler.  However, if it is too low torque it will start leaking filament -and if it is torqued to much the coupler contact area (toward the heath block) will form up as an elephant foot -that we know all about.  😏

 

For this reason, the part of the coupler that meets the upper flange of the heath block is rounded off and this allow for some little expansion. This is actually the reason for the little ring we'll see after using the "atomic Bob's" method when cleaning the nozzle.

 

When I'm tightening this nut, I'll check that when the aluminum spacer just beginning to have contact then I'll tighten by turning the nut about 15-20 degrees. It should not be to tight but also not to loose..

After this, I put a marker line from the nut to the bottom aluminum cooling plate using a (black) permanent felt pen.

This is a marker to have for you to inspect that it's staying in place or if you need to readjust..

(You need to check that there is no leakage, also note that fast printing will increase pressure inside the heat block.)

 

It is also wise to check your new coupler for proper flatness 90 degrees, it should match well.

 

Well, I'll never had any leakage from my nozzle using this method.

 

Good luck

Torgeir

 

 

 

 

 

 

 

 

 

Edited April 5, 2021 by Torgeir
More info added for clearification.

[friedl_basson 5]

Hi @Torgeir - 

 

Wow, thank you for the thorough explanation, it is much appreciated.

 

Just for more reference, I am using to original Ultimaker nozzles only.  I received a set with the UM2+ upgrade kit I purchased.   For now, PLA seems to be printing fine at 220C so I will stick to this until the current project is over.  I will then be able to afford some downtime on the printer 🙂 

 

I ma trying to print a functional prototype for the client now using CPE which seems to be a whole different set of problems altogether, hehe.  First layer was fine, second layer was a complete mess, see attached.

 

I will browse the forum to see if there are any tips on printing with CPE.  Thank you again for your help!

 

Kind Regards,

Friedl!

[Carbon 28]

Have you Re-Calibrated the Decouplers since you had the "filament stuck" issue?

 

https://support.ultimaker.com/hc/article_attachments/360013097260/Ultimaker_S5_Material_Station_-_Decoupler_calibration_instructions_v2.pdf

 

 

 

[Torgeir 228]

Hi @Carbon,

 

We talked about the "coupler" that are inside the extruder of the UM2 family printers.

 

Thanks

Torgeir

[friedl_basson 5]

Hi - 

Just an update (and my apologies for the late response):

 

Just to be clear, the filament was stuck in the feeder, not extruder.  Nevertheless, I manage to find the problem.  Upon the reassembly of the feeder, I did not install the tension screw correctly hence resulting in very little traction on the filament.  I reinstalled the screw properly and like magic, all problems seem to be a thing of the past.  Well, all but my CPE woes... they seem to be never ending 😄

 

Kind Regards,

Friedl