Changing an UM2 from 12.5 micron to 6.25 micron resolution on (X & Y) axes.

[Torgeir 228]

Hi Folks,

 

So why this kind of modification you may ask?.. Well, most of my objects is small mechanical parts (95-97)%! In fact could be printed on an UM2 Go, the most accurate printer made by UM, (IMO). As I wanted to have some improved finish, this had to be tested. This modification was easy as the pulleyes on both (X & Y) stepper motors had to be changed from 20 tooth 16 tooth and the pulleyes on the two 8 mm axis is changed from 20 tooth to 32 tooth. So instead of 1:1, it is now changed to 1:2. I’ve made (printed) a new stepper adapter in order to use the same belt as before.

 

 

I’ve also made a change to the Z-axe setting from 8 step to 16 step (installed a link). However, this latter one is not the one to take easy -as it will influence your filament flow demand and a few other parameter as well. After this change (16 step) you cannot see the horizontal lines when printing high resolution with bare eyes. I’ll probably go back to 8 step as Cura do not handle such a modification just like that..

 

 

So how was the effect this modification, this is good for small details in the printed object as long as you use 0.25 mm nozzle, but not so much noticeable when using 0.4 mm nozzle.

Also, the surface of the object is smoother..

 

Note: The firmware has to be set using G code in order to set proper status of the printer.

 

Minus, stepper motor makes more noise, so I'll guess implementing the silentStepStic module will fix that..   Probably my next topic, if time allow..

 

Ok. Here's some pictures:

 

X-axe stepper before modification.

 

X-axe stepper after modification. (Note the adapter plate)

 

Y-axe stepper before modification.

 

 

Y-axe stepper after modification.

 

 

Z-axe 8/16 step connector, where a link must be installed to have 16 step mode.

 

 

Thanks

 

Torgeir

 

Edited February 15, 2020 by Torgeir
Text edited.

[tinkergnome 926]

5 hours ago, Torgeir said:

I’ve also made a change to the Z-axe setting from 8 step to 16 step (installed a link). However, this latter one is not the one to take easy -as it will influence your filament flow demand and a few other parameter as well. After this change (16 step) you cannot see the horizontal lines when printing high resolution with bare eyes. I’ll probably go back to 8 step as Cura do not handle such a modification just like that..

 

Hi @Torgeir,

that's not because you changed the micro-stepping mode, but because you print with very very thin layers?

Or do i got it wrong? Can you explain it a bit more? What's the real issue that you're talking about here? What has material flow and Cura to do with the micro-stepping?

 

5 hours ago, Torgeir said:

So instead of 1:1, it is now changed to 1:2

 

More questions.... 🙂

Have you tested the maximum achievable speed? Does it still reach 300mm/s travel speed or will this burn the motors down?

Can the poor little mega2560 hold up the pace?

 

[Torgeir 228]

Hi @tinkergnome,

 

No, no micro stepping, just the fact that line height is halved.. When the initial layers is to be printed the feeder start skipping due to high feed for such a tiny layers. So I’ll have to readjust either flow or initial layer height some to avoid this to happened. When pirinting is started I can only adjust the flow on the printer (UM2).

 

 

 

Well, I'll only go to 150 mm/s travel or printing speed as the stepper is at max speed and will start to stall and loose steps if I'll try to go faster.  The mega2560 does fine, but the poor heated stepper drivers is kind of hot..

 

I've tested it up to 250 % increased speed at initial 60 mm/s printing a standing tube in spiralized mode. It made this, but would not do this again. 🙂

 

But if I just keep 60 mm/ s printing, it is fine.

 

 

Thanks

 

Torgeir