"Manual" multicolor  

RE: "Manual" multicolor

Hi, in my experience, it is no problem to do more colors, if there are not that many filament changes. I did some signs with 4 colors (name tags for consilia-brno.cz, see picture), but the changes were only in 1st layer, so it was totally feasible to do these 3 or 5 changes (I wanted to start with specific color because MK4 mesh probing can leave some filament specks on bed so it was 5 changes for me).

Try to slice what you need in a slicer and see how many changes you end up with. 
In short, I think this manual method is great for signs or a release support layer when needed. It enables the way how to do more colors/materials, without having to hassle with MMU and more complicated filament loading and much more desk space needed for the MMU. 

RE: "Manual" multicolor

This method has been working great for me with one tiny exception. Would love some help on how to solve if anyone knows. 

After the printhead stops, moves up and over to do the manual color change, it will go back to the part and tap where it just finished printing from. Because of the tiny bit of ooze that happens in that moment of contact it will leave a spot of the new color in the previous color. 

So, is there a setting or even some manual code manipulation that can tell the print head to not do that tap and instead just proceed to the first contact point of the next layer?

Any help would be greatly appreciated.

RE: "Manual" multicolor

It would appear that the M600 command is not fully implemented by Prusa
https://reprap.org/wiki/G-code#M600:_Filament_change_pause

As you will see in the link and the image above
there is an additional parameter (N)  which is supposed to prevent exactly this issue... But I never got it to work...
One option  (If you have enough layers available, is to change colour on layer  higher, in this case the printer will still do the beauty spot trick... BUT, the beauty spot will be under the area of the new colour on the next layer so you won't see it

Another option is to add a saccrificial part as an additional part, after the main model, this should result in the beauty spot ending up on the saccrificial part. 
Another option is to enable a purge tower and the spot should end up there. 
and a last minute option, if you have forgotten the other options, 
Lay a sheet of paper over the model when you are changing the filament, let the printer deposit the beauty spot on the paper, then whip it out of the way... and let the printer continue

I hope this helps, 
regards Joan

RE: "Manual" multicolor

Thank you so much for the quick response Joan <3

I have tried two of your recommendations already. The wipe tower and the paper.

The wipe tower for whatever reason didn't seem to help. It still does the tap on the part before going over to the tower. I kept it on anyways cause I am using a dark blue and white and the extra purge helps keep the white brighter.

The paper trick does seem to work but I need to raise the travel height a bit so it releases it easier. I was hoping for a safer solution as the tap spot and the start location it picked were so very close it was hard to time the removal.

I will try the sacrificial part next. If I do that and it works like you say (add it after the main part and it will print second) then that is a fairly easy solve.

Not sure I understand how to implement your first option (color changing on the next layer). Would that be something in the slicer or a manual gcode edit?

Again, thank you so very much for you help and expertise!

RE: "Manual" multicolor

So, is there a setting or even some manual code manipulation that can tell the print head to not do that tap and instead just proceed to the first contact point of the next layer?

I hate this... I had an issue where the last thing that was printed was the inside of an A, then after the colour change, it would go back, and pull the little triangle off the A... Such a pain, in the A.

I tried a purge tower, which exists to stop this right? But it did some weird stuff where it would make a huge blob in one spot. My work around was to insert a generic box, make it 50 x 1 x 0.2 (or whatever layer height you're using), and put it just in front of the model. After it finishes the text, it does this faux purge line, then changes colour. After the change, goes back to the end of the generic box, and then carries on with the next colour.

I also made sure to enable a couple of skirt loops as a way to ensure the pressure was right between colour changes. Let us know how you go.

RE: "Manual" multicolor

I modeled a 10mm cylinder with a 5mm circle of the second color in the middle at the same layer height. Then after I placed the main object, I place the cylinder and arranged it in front of the main object. Apparently the order in which you import the objects and arrangement both affect when they will print. Once that was done the tap happens on the sacrificial object and all is well.

Now I just need to get my flow multiplier dialed better to keep cleaner margins ... but I know how to do that.

Again, thank you all for the help. 🙂

RE: "Manual" multicolor

Hello, 

I'm trying to print some medals with number in the middle of one circle and I would like to change the print when the number is printed. 

I saw your steps, but I don't see or instead where to place it. In the personnalized gcode, I've already some gcode line but where do we have to add the M600 ?
I know than it's an old post here, and hope than someone can see my message and help me. Thanks in advance. 

At the simplest (but you should really read the whole thread) copy your printer definition and save it as ManualMMU so you have a new printer in the list -

then in Printer Settings > General  set the number of extruders you wish to emulate.

In Printer Settings > Custom G-code scroll down to: 'Tool change G-code' and enter  M600 followed by  return keypress.  Save the modified definition.

From now on this definition will enter the change code as required and you design for  it in the same way as for an MMU or a multihead XL.

Cheerio,

RE: "Manual" multicolor

Since Prusaslicer v2.7.4 using virtual extruders for single extruder multicolor is broken for me and I can't see why. I used exactly the same settings, but since v2.7.4 my printer produces these blobs and does rattling noises when unloading the filament.

I experienced this behaviour when I started experimenting with single extruder multicolor, but never had this since I used these settings:

Did Prusa change any parameters we can't see? Is it in the profiles?

I attached a ZIP-file with two projects, one created with v2.7.1 and the other with v.2.7.4, same settings