Low quality printed text  

RE: Low quality printed text

Hi Georgie, 
I Can't find your 3mf file  the link takes me to Printables  but I Can't find the file... 
Could you Zip Compress it, and attach it here? 

When I started using Manual MMU I was under the impression that the Purge tower was not appropriate. 

Now, I believe it is useable. 

are you printing the panel face down? 
Are you using virtual extruder 1 for the black and virtual extruder 2 for the blue? 
Are you using Arachne perimeter generator? 

It looks like you may be getting a bit of stringing and a bit of elephants foot and possibly arachne is changing the shape of the characters... 
If you are using Arachne, try classic perimeter generator

Try Blue in virtual extruder 1, so that it claims it's space on the build plate before the black in extruder 2
Keep the temperatures low enough to prevent stringing. 
Try again

Regards Joan

RE: Low quality printed text

Hi Joan,

Thank you for replying so quickly !

How can I attach a zip file here? I did it using the Add Media button, but I see I was wrong. I have spent half an hour looking for an Attach button... 🙁  I feel stupid.

Are you printing the panel face down?

Yes, the text is facing the heating bed.

Are you using virtual extruder 1 for the black and virtual extruder 2 for the blue?

Extruder 1 for the shape box (black) and extruder 2 for the text (white)

Are you using Arachne perimeter generator?

Yes, perimeter generator is set to Arachne.

It looks like you may be getting a bit of stringing and a bit of elephants foot and possibly arachne is changing the shape of the characters... If you are using Arachne, try classic perimeter generator.

OK, I will !

Try Blue in virtual extruder 1, so that it claims it's space on the build plate before the black in extruder 2.

Oooooh! This is a very good idea ! I will invert extruders.

Keep the temperatures low enough to prevent stringing.

OK. I will set the nozzle temp 5°C lower.

Try again

Thank you so much Joan for these instructions. I am still a beginner in the 3D printing domain and I am learning a lot.

Regards,

Georges

RE: Low quality printed text

Hi Georges, 
'Attach file' is at the bottom left corner of the text input box, just outside the dialogue box. 

Good luck with your tests

Joan

RE: Low quality printed text

Hi Joan,

How could I miss it !? 🙄   I will test your suggestions today and I will let you know. Thanks again !

Georges

RE: Low quality printed text

I am excellent at missing the most obvious... so I understand. no need to appologise

regards Joan

RE: Low quality printed text

Hi Joan,

Here is what I get from your recommendations. That's better, but white letters are not so... white. Do you think increasing the depth of the text modifier could improve whiteness? I have attached the zipped project file. There was a short extrusion of black PLA after filament change, above the 'L' letter, just before the nozzle moved to the wipe tower. It's very difficult to catch this small amount of filament before it gets colder, not to mention the risk to remove text by pulling the excess of melted black filament. Should users perform such actions to get a perfect result? If yes, I wonder how one can rely on the MMU device...

Regards,

Georges

RE:

Hi Georges. 
different white filaments have different opacity. 
Prusa Signal white, is a good strong white, many others are more sort of watery, 
additional layers behind light colours can help immensely but it always leads to more colour changes, which can be a pain with Manual MMU. 
Did you clean the nozzle before you started? 

is it possible that you are over extruding a little?

Here is a reply I Typed recently, It may help...

Managing the waste pile and filament change is a bit of a pain, manually
https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-hardware-firmware-and-software-help/large-blob-on-wipe-tower/#post-698679

The MMU3 finishes a section of say Blue Lettering. Then moves to the Purge Block, 
Wipes the extruders nozzle, then re shapes the filament tip, before withdrawing it. 
it then loads the next filament and wipes the mixed filament un the purge block, until it hopes the colours have changed, at which time, the printer returns to the print

this was Manual MMU, and I got a blot behind the white over the 'i'
the whole card was 0.8mm thick

Joan

RE:

When you change to the black, gently hook the expelled filament over your finger and press ok for correct filament load. Some more filament will extrude so wait till the head starts to move and follow toward the print. Hold on as late as possible before pulling the filament away to ensure you don’t leave any soft filament at the nozzle. 
An extra layer of text will improve its opacity. 

Minimise elephant foot compensation. 

RE: Low quality printed text

Hi Joan,

I'm going to order one PETG Signal White spool.

additional layers behind light colours can help immensely but it always leads to more colour changes

I will run my next test with a 0.8mm depth for the text modifier.

Did you clean the nozzle before you started?

No, I didn't. I'm using a silicon sock to protect the hot end. I'm going to clean this sock.

is it possible that you are over extruding a little?

Maybe... I don't know.

Large blob on wipe tower...

I have parsed the firmware source code on Github. M600 N is not supported by the MK4 firmware.

I now do the colour change one layer higher than normal, so that the touchdown position for the beauty spot, is under the print area of the new colour

Ooooh ! Nice trick ! This is implemented in PrusaSlicer 2.7.2-alpha2 !  https://github.com/prusa3d/PrusaSlicer/releases    Look at Color change (M600) improvements

Thank you for your help, Joan !

Georges

RE: Low quality printed text

Hi John,

An extra layer of text will improve its opacity

I will do this for sure.

Minimise elephant foot compensation.

I have to study the meaning of this... 😉 

Thank you for your help !

RE: Low quality printed text

Elephants foot compensation makes the first layer outline smaller than the others to allow for it spreading under heated pressure, as I understand. Anyway the text might suffer if the adjustment makes the text smaller.