Totally despondent

[tojiero 8]

I'm having huge difficulties with my Ultimaker 2+. I have owned it for more than a year now and I'm still not able to get predictable or particularly satisfactory results from it. The combination of Cura settings and machine settings is a minefield of complexity. I cannot get a handle on where settings are being driven from. At the moment for example, no matter what I do, the machine insists on printing PLA at 240C with very messy results. Materials settings in the machine shows PLA at 210C but when I print something it 'strings' all over the place. If I then look in 'tune', it shows nozzle temp at 240C. The gcode was generated as PLA but the temperature settings appear to be hidden. Where is this 240C coming from ?!

I've read through many tutorials that just say how wonderfully simple and intuitive it all is and followed instructions to the letter. 'Getting Started' examples for download are stl files with no gcode. I have reset my machine to factory defaults several times. Cura has been updated and has a totally new look now. The hints and prompts on settings are usually meaningless dead ends and every link to 'support' on this website leads to an article about how good their support is, instead of actual support.

I have been trying to print a large but simple shell like part in PLA now for 3 days without success. I am very frustrated, disappointed and desperate for help now.

 

 

 

 

 

[SandervG 1,518]

Hi Tojiero, 

 

thank you for your post. In order to help you I have some more questions for you:

Could you share a photo of your print, please? Do you have retraction enabled?

And are you able to tell us if that print had full default profile from Cura or did you make changes?

Have you always printed with PLA, or also abrasive/high temp materials?

Have you ever replaced any parts (like a TFM coupler or something?) 

 

 

[gr5 2,004]

Well first of all it's fine to set the temp manually in the tune menu after it starts printing the skirt or brim.  It should stick with that temperature as long as there are no temperature commands in the gcode (which is extremely unlikely or you wouldn't be having this issue).

 

So on the UM2 the nozzle temp is associated with both the material and the nozzle size.  For PLA, I think the defaults are around 210C for the 0.4mm nozzle and possible 240C is for the 0.8mm nozzle?  Are you using a 0.8mm nozzle?  The cura/um2 defaults work best for me with the 0.4mm nozzle.  If you want to print with a 0.8mm you may have to override a few things.

 

Fixing this permanently is tricky.  In the materials menu there is an option to write the materials settings to a file on the SD card then you can bring that to a computer and edit it with a text editor (like notepad on the pc) and fix the temperatures associated with your material (I assume PLA).

 

1) Are you using a 0.8mm nozzle?

2) Did you mention that you are using a 0.8mm nozzle possibly in cura?

3) If you look at the gcode file with an editor - near the top it should say the nozzle size that cura thinks you will be using.  What does it say?  That's where Marlin (the firmware inside the UM2) get's its information about what nozzle you are using.

[tojiero 8]

In Cura, at the top of the menu, there is a selection of materials. There are several PLAs listed (in the main list and in an 'Ultimaker' submenu list. My material carries the Ultimaker brand name so I selected the appropriate colour from the Ultimaker submenu. Written on the the spool is a temp recomendation of 200-230C. After installing the material on my UM2 and selecting PLA on the UM2 menu, it shows a temp setting of 210C. When I start to print the machine shows a nozzle temp of 240C.

In the next fields, I have selected 0.8mm nozzle and 'Recomended'. With recomended selected you cannot see hardly any setting values so I don't know what i'm running. If I try changing something in Custom I lose the (invisible) Recomended settings and cannot see how to reset. If I click back to Recomended, the slice time doesn't change, indicating that the settings have not reverted. I have changed the Infill %age and even after closing and restarting the app it holds on to those changes. 

[tojiero 8]

I have reset my UM2+ to factory settings and copied the 'material.txt file then read it in Notepad.

Apparently the nozzle temp for PLA through a 0.8 nozzle is factory set at 240C.

Is this correct even though it's outside the range (200-230C) quoted on the Ultimaker branded material label?

The temp. value I'm seeing in the UM2+ Materials Setting is a temperature value given immediately following the material name in the MATERIAL.TXT file and doesn't seem to have any relevance to anything.

At least I have found where the nozzle temperature is driven from now.

Thanks gr5, for pointing me in the right direction.

 

[tinkergnome 924]

20 hours ago, tojiero said:

Apparently the nozzle temp for PLA through a 0.8 nozzle is factory set at 240C.

Is this correct even though it's outside the range (200-230C) quoted on the Ultimaker branded material label?

 

Yes, it's the correct (recommended) temperature:

https://ultimaker.com/en/resources/22225-how-to-print-with-ultimaker-pla

[gr5 2,004]

PLA has a large printing range from around 170C to around 240C.  It is much thicker and more viscous at 170C so the feeder has to work much harder.  Like toothpaste.  At 240C it is more like honey.  So if you want to print faster it helps the extruder if you raise the temperature.  But if you want better quality you have to lower the temperature so the filament stays where it is once it leaves the nozzle instead of spilling out, etc.  But if you lower the temperature you also have to lower the volume per second so you don't exceed the ability of the feeder to push.

 

If you are printing 40 cubic mm per second you will indeed want the temp at 240C.  So for example 0.6mm layer height with 0.8mm line width and 83mm/sec printing speed.

 

But the part will not look very good.  Maybe that's fine.

 

But if you want the part to look nice, try 0.3mm layer height, 0.8mm line width and 40mm/sec and 210C.  You will get nicer overhangs and walls with less bumps.

 

Yes the printer is sort of "intuitive" if you print with the standard 0.4mm nozzle but when you venture away from the most basic settings you will also have to do more tweaking to get things the way you want.  For example if you hate "ringing" you will want to make sure acceleration control and jerk control is enabled (it is by default). But if you care more about dimensional accuracy of your parts you will probably want those turned off.

[tojiero 8]

"If you are printing 40 cubic mm per second you will indeed want the temp at 240C"

So where did the example figure of 40mm^3/sec come from? Is that a spec of a 0.8mm nozzle?

 

".......try 0.3mm layer height, 0.8mm line width and 40mm/sec and 210C....."

This implies a flow of around 10mm^3/sec. I'm assuming (from the temp) this would be using a 0.4mm nozzle.

 

Is there an ideal printing volume flow (or range of) for each nozzle size and material?

Would that be a good place to start from?

 

[Torgeir 212]

Hi tojero,

 

I looked into your previous posting and found more information about your problems.

 

In here you asked 3 questions, just continue this tread..

 

1)

 

"If you are printing 40 cubic mm per second you will indeed want the temp at 240C"

So where did the example figure of 40mm^3/sec come from? Is that a spec of a 0.8mm nozzle?

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

Yes this is the 0.8 mm nozzle.

 

2)

".......try 0.3mm layer height, 0.8mm line width and 40mm/sec and 210C....."

This implies a flow of around 10mm^3/sec. I'm assuming (from the temp) this would be using a 0.4mm nozzle.

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

No, this is also a 0.8 mm nozzle.

(Here we use lower print speed and nozzle temperature in order to have nicer looking print.)

 

3)

Is there an ideal printing volume flow (or range of) for each nozzle size and material?

Would that be a good place to start from?

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

Use the default nozzle size: 0.4 mm

Use the default print speed: 60 mm/sec.

However for detailed printing we may go down to 30 mm/sec. -or even slower.

Using PLA and default temperature 200 deg C. (Temperature might be lowered to 180-185 deg C.)

The maximum flow for an UM2+ is typically 10 mm³/sec. When using 0.4 mm nozzle.

 

Thanks

Torgeir

Edited March 28, 2020 by Torgeir