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Unexplained patterning in our prints

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Posted (edited) · Unexplained patterning in our prints

Ok, so I decided to do a set of test prints today experimenting with the feeder tube using a longer tube or shorter tube and seeing if it changed anything...

And I discovered that the problem has somehow overnight become ALOT worse.

Something seems to be slowly failing, causing the problem, but for the life of me I have no clue what it is. The motors all seem to be working well (both feeder, X, Y, and Z)

Photos from today:

C9blHcQ.jpg

gb7Trfa.jpg

agb5wZp.jpg

IMGUR album:

http://imgur.com/a/eR4pB

Edited by Guest

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Posted · Unexplained patterning in our prints

Again, it "kinda" looks like under extrusion, but it is not uniform across a layer, and the problem is repeatable layer after layer in a way that makes patterns.

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Posted · Unexplained patterning in our prints

Hmm. This looks worse than ever, like you said...

However, you touched something here.

For this problem it is not that important that the length of the Bowden tube is plus minus a cm or so (the normal length of the Bowden tube is 705 cm if I’ll remember right). The most important is that the Bowden tube is all the way down into the” Teflon coupler” and WELL locked with the white “knife lock” at the top. When you lift up this white lock, the small knifes will be forced (due to the cone) toward the Teflon Bowden tube. So you really need to keep this "lift" pressure up to assure a correct lock.

On my printer one clip (red or blue) is not enough in order to keep the Bowden tube in place so it would not slip, I must use two!

The same is true on the feeder side off the Bowden tube were I also had to use two lock clip. You should not have any play here.

So keep focus on the Bowden tube lockers.

Again, on my printer, one clip did not hold at all. Have a closer look on the white lockers to see the small knifes.

The length specified for the Bowden tube is more about movement freedom and prediction number of steps the feeder need to go, due to "auto" feeding, so it do not ram into the extruder at full “mating speed”.

I can’t think of anything else that can make such a strange pattern. Hmm...

 

Anyway, good luck.

Regards

Torgeir.

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Posted · Unexplained patterning in our prints

Ah apologies, I mis-interpreted your message.

Yes the feeder tube is well locked. It has deep marks on it from where the "teeth" grip the tube, and it is all the way down to the teflon coupler. I can pull upwards on the tube with a large amount of force before it starts to slip.

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Posted · Unexplained patterning in our prints

Ok. No problem, next time it's my turn... :)

This new pictures are all really different compared to the green rocket. Here I’ll think we can see massive under extrusion. As you say this is printed with Colorfabb XT, which I have no experience at all with, however I recall that the XT is demanding a kind of high extruder temperature, right?

Then I come to think about you have changed nozzle to the Ohlson block type, as I’ve also think about doing. I know you can buy this block with four different nozzles, a screw driver and a 6 (?)mm pipe to change the nozzle with. I’ve understood that many people just use the standard heater, said to deliver 25 Watt. Did you also change the heater?

If you still are using the standard heater, this might be the problem, and also somehow explain why the print stay up even with such an under extrusion. This can occur if the heater element (plus block) does not have enough heat capacity to melt filament as fast as we (well, the print) demand.

As a test you can reduce the print speed,quite alot , in order to conserve heat capacity for the amount of filament required any time for this print. Then Just do a little print to see any improvement.

Also be aware that, the outer shell of the heater might be higher than the core temperature here.

You never said that you have installed a 35 Watt element, I’ll think –so I assumed a standard heather element.

Just a shot in the air…

Ok. Good Luck.

Torgeir

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Posted · Unexplained patterning in our prints

Just a few crazy ideas.

Can you try to:

- Check if the olsson block isn't touching the metalfancap, or any cap you use. If so, that can create very weird heat fluctuations that sometimes can't be seen but affect the print.

- Check the nozzle doesn't touch any part of the fancap.

- Check that the heat sensor it's fully 'in' (make photos)

- Check if there's any movement on the coupler (up/down) when printing and retracttion occurs.

- Take out the bowden and check if it has any weird curve or if it's just fine.

Just a few crazy ideas that can't hurt to check.

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Posted · Unexplained patterning in our prints

Torgeir,

Will give it a shot on a very slow setting and see how it works, but given both the internal thermometer and the external IR camera say the temperature is good, I'm skeptical this is the issue, however I have no better ideas!

Neotko,

Thanks for the feedback. Addressing your points one by one:

- When I first installed the Olsson block it was touching the metal cap and giving a heater error. I have since increased the distance and there is now plenty of clearance.

- Nozzle is not touching

- Heat sensor is fully in. I do not have my camera with me today but I will take a photo tomorrow.

- Coupler does not move.

- Bowden tube is a little short but otherwise fine. Have tested using a tube a few centimeters longer and it does not appear to be an issue.

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Posted · Unexplained patterning in our prints

Today to double check I took a lot of the printer apart and oiled everything that could possibly need to be oiled, the motors, X Y and Z axes, etc... (Motors, X and Y axes with machine oil, the Z axes with the Ultimaker provided grease)

No effect (as expected).

Currently doing a print at 25% speed as requested by Torgeir.

(I must hold the world record for number of prints of this particular rocket model that I'm using as my primary test print! And yes, I have used other prints and the problem also appears there as well)

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Posted · Unexplained patterning in our prints

Could that be a slicer problem too? Or wrong settings in Cura or whatever slicer you use? For example a check box that got (de)selected inadvertently?

This weird but very regular pattern makes me think of those art lamps that do only print the 3D-mesh of a model (the "fish net"), but not the infill.

Or a defect in the SD-card or card reader, where it only reads data partial, but skips other parts? (Try a different card, or remove it a few times to clean the contacts.)

Has the exact same gcode-file worked well in the past, or did you slice and save the gcode again recently?

If you manually extrude material ("Move material") by rotating the wheel smootly, does that extrusion flow in an equal, nice stream? Or is that intermittent too? If equal, it looks like software to me. If intermittent, it looks like hardware.

I am just wildly guessing here, but it might give new ideas?

Geert

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Posted (edited) · Unexplained patterning in our prints

Hey Geert,

Thank you for your response.

1) I have tried multiple computers, multiple different installs of Cura using different versions. No change.

2) I agree it is quite weird... It would actually be quite difficult to get the printer to do a fine mesh like this on purpose.

3) Have tried multiple SD cards. No change.

4) This patterning appears on all prints to some degree, even on the default "comes with the printer" g codes on the original SD card that came with the printer. (Hence the "Coffin's Cube" in my first image, that is the default gcode without any modifications on the original SD card)

5) Manually moving material works fine.

I have tried reflashing the software on the printer and making sure I have the most up to date firmware. All good, no change.

As requested by Torgeir, here is a print incredibly slow (at 25% speed): The problem still exists, but is not as obvious. You can see it in the first few layers, then it kinda blends together, but weird patterning is still visible in the walls of the print.

Ot7vCzx.jpg

Sb4ELXP.jpg

Edited by Guest

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Posted · Unexplained patterning in our prints

Hello,

And what is the result if you just manually extrude material? Thus "Move material" in an as smooth as possible way?

This pattern sort of reminds me of LCD- or LED-display panels where a couple of X or Y datalines have bad contacts. Or an digital-analog converter where a dataline is broken.

If you haven't done so, I would suggest checking all connections, all wires, for intermittent broken/bad connections. Especially those that are subject to movements (near the print head), and that are related to temperature and extrusion: temp sensor, heater, feeder motor. It could be broken solderings or wires, or a damaged connector pin, or so. This can be very difficult to find, since it is intermittent. What part of the printer have you worked on just before the problem started, and what was changed or touched at the exact moment before the problem appeared?

Geert

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Posted · Unexplained patterning in our prints

Hi,

Great, I like this one much better, even with the same problem...

I'll think the problem is the lack of enough "heat capacity".

The stringing we see here is “maybe” due to rising temperature -and "oozing".

You never said what kind of heater you are using, are you using the standard heater?

Well, -a good example of this kind of problems is the simple extruder test with PLA.

In this test you start extruding; 3 mm³/second. Then the flow and the speed are increased gradually until we reach the top where there is extruded 10 mm³/second. This test takes just about 10-11 minute.

Normally I'm printing PLA at a temperature 203 Deg. Celsius. To be able to do this test without under extrusion you are recommended to set the temp to 240 Deg. Celsius!

I do not have Olsson block, but just the basic one with 0.4 nozzles.

I’ve also been reading about Olsson’s recommendation, he said the old heater “can” be used, but for high demand material you must use a 35 Watt element.

The XP printing temp is from 240-260 Deg. Celsius. Hmm...

As some heater elements might have (delivered with) less effect that others, it might be time to measure the resistance of the heater element in order to find the effect of the heater.

Let’s check the resistance in the element.

The effect of a standard element is: P=U*I.  The resistance is: R=U2/P.

The standard element resistance (Rs) is:  P=25 W and U=24V. Then we have: Rs=U2/P=24*24V2/25W=23.04 Ohm.

The “Olsson” element resistance(Ro) is: P=35W and U=24V.   Then we have: Ro=U2/P=24*24V2/35W=16.45 Ohm.

Note: In an element like this, the resistance will increase a little as the temperature increase.

Ok. What do you think?

Torgeir.

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Posted (edited) · Unexplained patterning in our prints

Hi again,

I did not say this, but I've studied the last print very much. As I've got a fantastic program named "Paint Shop Pro", made when Windows 95 was new...

(This program still works well, even with Windows 10!)

When you look closely to the print, you can see the printing sometimes looking toward what it should be.

Said that, we need to do what we do more…

Strange, but we would have to print even slower, or increase the temperature (if we can, but with some risk) in order to improve.

The green rocket prints, was done with some slack in the Bowden tube. Due to this slack, the printer had a “little” time out, yes a little rest so the temperature could climb a little, this is why we could see some normal printing.

When the slack is gone and the speed is decreased, but not enough, this is what we can see now. The miss is very much shorter, but still very visible.

I’ll think this is an improvement, so it’s time to try the next…

Yes, I’ll know you’ve been printing so many times…

How about this; You’re printing several objects on the same shot, I’m printing one by one. So if I see there is some problem after -say print no 7, I will have seven good prints, -at last.  :)  Yes, or no, hmm.

Have a look on this!

There is a very good topics, a must read;

Custom heater block to fit E3D nozzle on Ultimaker 2 ("The Olsson Block")

--------------------------------------------------------------------

esteban-pachecoTalented TechLevel: 15 Points: 219

Posts: 165Location: GermanyPrinters: Ultimaker 2

Posted Jul 2, 2015 - 10:25 PM • Edited  Jul 3, 2015 - 10:38 AM

Hello Forum!, i've been printing for a while with an Olsson Block, and i want to update the information and share my experience with this upgrade ( I TOTALLY RECOMMEND IT)

after getting the Olson Block, i experimented a temp error because in this  block, the nozzles is more influenced by the side fans, plus the weakness of my Heater Cartridge, it other words, it was unable to deliver the amount of energy required (above 230 C), usually wen having the fan at 100 %.  Following the advice of many people in here, i got convinced to change the heat cartridge to a more powerful one (35 W) i was kind of sceptic, because I'm very careful with electronics ( one error and that'S it).

so far everything is working just fine, theres a few remarks:

A) theres some little fluctuations in the temperature.. (-+ 1 C), thats not so dramatic...

B) if you're printing lets say at 215C, and you want to go to 210 C, the temperature will go for a few seconds below 210 C (say 204) but it will recover quickly and stabilises at 210 C, and stays so.... the other way around, i haven't seen any strange behaviour.

C) i just got Once the Temp error, i was testing the configuration and i turned the temp to 260 C and fans 100 % Suddenly (usually i don't print anything above 235). so thats also NOT a big deal...

I'm really happy now, ill keep you informed about my experiences...

-------------------------------------------------

Start reading from here:

https://ultimaker.com/en/community/8689-custom-heater-block-to-fit-e3d-nozzle-on-ultimaker-2-the-olsson-block?page=27

Ok. Mate,

Good luck.

Torgeir.

Edited by Guest

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Posted · Unexplained patterning in our prints

This is simply underextrusion. In most cases caused by a worn out PTFE coupler.

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