Almost always missing layers / underextruding

[gr5 2,194]

I also have UM Orange so that's a good choice.

 

[woofy 12]

Today I had my first batch of Faberdashery filament arrive, so I thought I'd do a side by side extrusion test with UM Blue and Faberdashery Arctic White.

Both at 230C

UM Blue fails at 5mm/S and Arctic White at 7mm/S

 

[mr.-waldorf 0]

Nicely done.

So once again it seems that at higher speeds PLA material doesn´t have enough time inside the nozzle to achieve the right temperature, and this can be improved with some PLA material who doesn´t need so much temp... with this in mind, UM White should be the worst material and Faberdashery filament should be the best...

I am starting to believe that a shorter nozzle is the guilty one...

 

[woofy 12]

I meant to post this a few days ago during yet another "Strip The Hot End" (sounds like a Morris dance).

I checked the temperatures with a thermocouple probe deep in the nozzle. Temperatures were set manually and allowed to stabilise.

TC UM2

17 15

53 50

106 100

158 150

208 200

229 220

257 250

Also checked the TC against steam from a boiling kettle, it read 100C but I think its reading a few degrees high.

I concluded there was no problems with the UM temperature control.

 

[mr.-waldorf 0]

Had to google for Morris Dance... Lol, now I get it :lol:

Morris dancing has been claimed to be a remnant of a pre-Christian Celtic, or Druidic, fertility dance...

 

[mr.-waldorf 0]

So once again, it proves that UM2 are very precise to achieve nozzle temperature, it´s the same here and it seems the same in all measurement temp nozzle tests/posts. Thank god for the pt100...

So new challenge, how can we measure the extruded filament temperature and compare it with an UMOriginal? (this should be more interesting at higher speeds where the underextrusion occurs)

maybe someone out there with a UM2, UM1 and a laser temperature gun??

Any thoughts?

 

[Nicolinux 288]

Hi,

I have performed the extrusion/measurement task. Set the extrusion speed to 60mm/min in Pronterface. Temperature was set to 180°. I extruded several strands of 30mm. But while extruding the extrudder started skipping. This produced visible deformations on the extruded filament. It looked something like this:

I measured in different locations and got between 4.8mm - 5.0mm (thickest) and 3.9mm - 4.2mm (thinnest).

I also managed to take better™ photos of the nozzle. It won't get better than that with my iPhone (and skills...):

EDIT: scale in mm

 

[3dmaker4u 0]

Well, I think 180C is far too low. 1 mm/s as the extrusion speed, counted at the filament level, not the extruded thread, for a 3 mm filament and a 0.3 mm nozzle (just to be simpler to calculate) is equivalent to... 100 mm/s printing speed! So, skipping is no wonder.

Actually, I have to admit I forgot the UM is working with 3 mm filament ;( My bad, and apologize for any inconvenience.

For 1.75 and a "regular" 0.5 mm nozzle, 1 mm/s of extruder speed is just 12.25 mm/s printing speed. Even for a 0.3 nozzle is less than 35 mm/s.

I think the methodology should be adjusted to be independent of the filament diameter.

So, let's assume we will extrude so that the printing speed is 20 mm/s (which is actually proved to work fine for 1.75 mm filament and 0.4 nozzle).

Then, going backwards, for 3 mm filament and assuming a 0.4 mm nozzle, the extruder speed should be set to 0.36 mm/s or 21 mm/min.

I didn't check George's graphs, but 180C might still be too low. But if does not skip at this speed, it's ok.

 

[gr5 2,194]

I thought 60mm/sec sounded very very fast. Unfortunately I am now travelling to NYC (amazing that I can do web stuff on a train) and won't be home until Sunday night.

I think you mean .39 to .42, not 3.9 to 4.2, right? Please edit your post and I will remove this line.

 

[mr.-waldorf 0]

Hi Nicolinux,

Maybe too fast and too cold?

 

[gr5 2,194]

I don't think nico needs to repeat his measurement. Extrusion slipped and pressure when to almost zero so since he measured at the skinniest spot this should be good enough.

 

[mr.-waldorf 0]

I measured my nozzle hole with a needle, tape and caliper and my nozzle is 0.42mm. So maybe my method isn't 100% accurate but it seems that I have some numbers as Nico...

Nozzle temp: 200ºC

 

[gr5 2,194]

Smart! I didn't think of that. Insert needle into nozzle hole until it stops due to getting too wide. Use tape or permanent marker to mark how far in the needle went. Then remove the needle and measure with caliper.

 

[mr.-waldorf 0]

Today I had my first batch of Faberdashery filament arrive, so I thought I'd do a side by side extrusion test with UM Blue and Faberdashery Arctic White.

Both at 230C

UM Blue fails at 5mm/S and Arctic White at 7mm/S

 

Hi WofysPlace,

It seems no body is paying attention to your findings... but I am very interested on them. (everybody is paying attention it's just me being an asshole )

Why do you think that Faberdashery's filament had better extrusion rates?

-Because it has a smoother surface and runs with less friction thru the entire material feeding system?

-Because it has a lower melting point?

I hope it's the last one, kind a helps my theory (and others) I will quote illuminarti because he has a better English and can express himself better than I

Quote: "A different challenge is getting the extruded plastic itself up to temperature in the first place, when printing fast, because the plastic spends very little time in the hot zone before being extruded, and so doesn't get up to thermal equilibrium with the rest of the hot end."

Maybe the nozzle hot zone is smaller than on a UM1?

 

[mr.-waldorf 0]

HEY ULTIMAKER R/D Team!!!

If you don't post your comments on this extrusion problems... we all start buying only Faberdashery filament to improve the extrusion rate and add a nickname to the UM2:

Fast&Furious

...they can print fast but leave the users furious!!

Just kindding, I love Ultimaker

Now more seriously, perhaps instead of posting your comments here, we can schedule a meeting and I will send one of my associates?

Crazy Harry

 

[3dmaker4u 0]

Very nice trick with the needle.

The only issue is about how to make sure the nozzle hole is peefectly clean. Of course, one may assume that by appropriately retracting the filament, it will get to the clear metal. Well, may be, or maybe not.

Anyway, do not use sharp stuff of tougher metal to clean!

[woofy 12]

Hi WofysPlace,

It seems no body is paying attention to your findings...

 

Oh I don't feel ignored, there were no questions looking for answers, just posting some observations. I know they'll be read and noted. The side by side result is very much in line with Illuminarti's results way back in this thread in posts #154 and #163. His was with Colorfabb instead of Faberdashery against UM Blue. I think is shows that UM filament is harder to extrude or needs a higher temperature. Apart from knowing it helps to use top quality filament, I'm not sure it helps improve the UM2 much.

The temperature results were posted just to eliminate that as a cause.

I certainly think the extruder is at least part of the problem and I'm following the "Ultimaker2 Extuder System - Improvements and Ideas" thread with interest.

 

[Nicolinux 288]

Hey guys,

I recognize the measurement of the nozzle tip isn't very accurate. I tried it this time with a needle. Inserted the sewing needle as far as it went and added a piece of tape to mark the point. Also tried to use a sharp pen to mark it. Depending on the marking method, I got 0.38mm to 0.40mm

@3Dmaker4U: Cleaning the nozzle is very easy. Just undo the bowden tube (head), push a piece of filament through the nozzle while it is hot. Then wait until it cools down to 90° and pull it out. You'll get a nice nozzle tip shape and a clean nozzle:

 

By the way. I printed the UM2 feeder in clear PLA, mounted it and printed the extrusion test again. For one this feeder produces some weird noise. Check out this vide (volume up)

 

 

The extrusion test failed again (printed as usual at 230°):

 

One thing was interesting though. The underextrusion patter at the top (I think at 7mm^3/s) looks very regular:

So yeah, still waiting for the teflon coupler...

 

[mr.-waldorf 0]

I certainly think the extruder is at least part of the problem and I'm following the "Ultimaker2 Extuder System - Improvements and Ideas" thread with interest.

 

I certainly agree with you on this, and those guys are making a very nice job...

 

The side by side result is very much in line with Illuminarti's results way back in this thread in posts #154 and #163. His was with Colorfabb instead of Faberdashery against UM Blue.

 

Funny... I thought that Ultimaker filament was from Colorfabb, my mistake.

 

[woofy 12]

Funny... I thought that Ultimaker filament was from Colorfabb, my mistake.

 

Its not Colorfabb:

http://umforum.ultimaker.com/index.php?/topic/1788-plapha-filament/?p=18691

I don't know who they use. I did see some speculation here once but I can't find it now.

 

[takei-naodar 0]

 

By the way. I printed the UM2 feeder in clear PLA, mounted it and printed the extrusion test again. For one this feeder produces some weird noise. Check out this vide (volume up)

 

 

The PLA is Rubbing somewhere.... probably one of the holes is to tight.

 

[Nicolinux 288]

Yes this might be. Already took off again. Using the stock feeder again.

 

[yellowshark 153]

Mr Waldorf asked -

"Why do you think that Faberdashery's filament had better extrusion rates?

-Because it has a smoother surface and runs with less friction thru the entire material feeding system?

-Because it has a lower melting point?"

Over the past month I have used 8 or 9 Faberdashery colours in production. Each has also gone through my test routine to establish optimum settings at a given speed/resolution.

They have all had very consistent diameters.

This has led me to the conclusion, absolutely, that the pigments used for colouring affect the extrusion rates and that doing these sort of tests using different colours, let alone, different manufacturers, is invalid.

I have also experienced the same affect with Colourfabb filaments.

 

[Nicolinux 288]

Each has also gone through my test routine to establish optimum settings at a given speed/resolution.

 

By the way would you like to share your filament test routine?

I have started a new thread here:

http://umforum.ultimaker.com/index.php?/topic/4432-filament-testing-routine/

 

[mr.-waldorf 0]

Thanks yellowshark, very nice info.

I noticed that with UM filament and you are quite right! Do you think that in overall Faberdashery filaments have a lower melting point than the others or they are very similar if we compare between same colors? or they are totally incomparable?