Mosaic 1.75mm conversion and Cura: under-extrusion

[Blizz 53]

Hey fellow makers,

 

I've recently converted my old and trusty UM2+ to 1.75mm with the mosiac convertion kit,  given that all my other printers are using that and I stopped stocking 2.85.

I do love cura though and don't want to use their (crappy, sorry) cloud software.

 

I've updated the printer settings to indicate it has a 1.75mm extruder, but I'm still experiencing massive underextrusion. Have to ramp up the material flow to 245% to get a good result.

Now, seeing that 2.85mm is about 2.65x the volume per height than 1.75mm, I'm suspecting that it is somehow still feeding as if it was 2.85mm and there is another setting somewhere that I have to update (e-steps perhaps?). Anyone who can help me out?

 

Thanks!

[Torgeir 146]

Hi Blizz,

 

Right you are..

 

265 % more E step. Your UM2+ use E369: So your new setting will be 369*2.65=977.85 ~ 978

New E step is 978.

 

Send this string to you printer:

 

M92 E978 (CR return)

M500 (CR return)

 

Printer will respond "stored"

 

That's all.

Good luck.

 

Torgeir

 

 

 

 

 

 

 

 

 

 

 

 

 

[Blizz 53]

Thanks, was pretty much the expected answer. I'll modify the setting and try again.

 

[3D_Dragoon 0]

I've got an S5 and just picked up the Mosaic 1.75mm conversion as well. I've never had to "send a string" to my printer before. Can you elaborate on how this is done for us newbs? I'm currently running the newest version of Cura on Mac OS. Is there just settings I can change in Cura or does this change have to be done via code?

[Torgeir 146]

Hi 3D_Dragoon,

 

Welcome in here.

 

Do not worry about this, as this is about an UM2+ that is converted from using 2.85 mm filament to 1.75 mm filament.

On your new UM S5 you will be using 2.85 mm filaments, so no such change is needed for you.

 

It is possible to make change in firmware, the program that is controlling the microprocesor.

It is possible to change a number parameter that is stored in flash memory.

By the way, this is not things to be changed often, normally only when we do some sort of modification, or hack as some name it..  🙂

 

Good luck.

 

Thanks

 

Torgeir

Edited April 17, 2020 by Torgeir
More info.

[Blizz 53]

@Torgeir he did mention he bought the conversion kit as well.

 

It's pretty easy, a .gcode file is just a text file, so all you need to do is create a new file, add the 2 lines and save as a .gcode:

 

M92 E978
M500

But you have to figure out what the normal e-step is so that you can adjust the number, 978 probably won't be the right one for you.

When done, just save it to your SD card (or however you get your files in the printer) and run it. It'll take a couple seconds and it's set.

 

Alternatively, just connect it via USB and you can send commands via the monitoring tab in cura. Sent the M92 command first and then M500 (as mentioned in the first reply)

 

I've removed the kit since then, not too happy about it, which is a shame.

On my UM2 the strand bends in the feeder and is just pushed in there.

Don't know if anything changed for the S5

Edited April 17, 2020 by Blizz

[Torgeir 146]

Hi Blizz,

 

I'm sorry i missed this, but what is this kit like?

 

I've removed the kit since then, not too happy about it, which is a shame.

On my UM2 the strand bends in the feeder and is just pushed in there.

 

Do you have a picture of this?

 

Thanks

 

Torgeir.

 

 

[Blizz 53]

It's basically a new bowden tube, a different lever for the feeder and an insert for the nozzle. In my UM2 feeder there is a bit of room between the knurled wheel/roller and the output to the bowden. The filament just "kinks" due to the higher speed and is fed within the feeder until everything jams. Guess that's one of the main reasons feeder/bowden type printers use 2.85mm 1.75 is more suited for direct drive.

 

I also really don't like that insert in the nozzle, it needs to sit perfectly or it gets pulled out during retraction. It would've been better if the kit was developed with a 1.75mm nozzle instead. I suspect that would make it more technical to install as ultimaker is more focussed on "just work" and less "tinker" and replacing a nozzle and recalibrating the bed is a bit more complex. No idea... That or a higher profit margin 🙂

 

[Torgeir 146]

Thanks for this explanation. I wanted to do the same and also got a 1.75 mm nozzle, but did not think about the upper space in the feeder. I'm also using the original feeder, but modified it with belt gear 1:2 and I have also installed a release handle.

I can put the filament in to start position, or feed it all the way to the extruder by hand.

 

🙂

 

[Blizz 53]

1 minute ago, Torgeir said:

I can put the filament in to start position, or feed it all the way to the extruder by hand.

Just to be sure: I didn't mean that it happens during filament loading (I always load it by hand up to the nozzle), it happens during printing

[Torgeir 146]

Aha, forgot -you have an UM2+ I've an UM2 with the old feeder..

 

Thanks.

[Blizz 53]

Feeder wise you'll probably have exactly the same issues. Mine was originally an UM2 but I upgraded it and can't remember that space not being there.