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raphi
(@raphi)
Trusted Member
Strange color problem

So I printed for 18h the part below and thought it will look very nicely once it's done. Which it does at a first quick glance but when you look closer you notice strange things:

The base is brown, the rest was printed with semi-transparent natural colored PLA. The brown seems to bleed into the natural PLA for quite a long while, while it is printing both colors (the bottom 5mm) but also after it stopped printing brown.

What's even more strange is the color change in the natural colored PLA later on. The left side of the shield appears to be much denser printed, the same is true for the pillar which is clearer above the height of the shield, there's a noticeable line in the pillar. The denser part of the shield seems to correspond to the pillar, my wife says it looks like the shadow of the pillar (which it is not ;)).

Does anyone have an explaination for this and maybe also a solution? I'd think that I could fix the color bleeding into the other by tuning the tower to print longer in one filament, but I don't know how to do this in Slic3r. And what can I do about the apparent color change in the same filament after printing two parts with the same color?

I suspect two possible reasons: this was printed with EasyFil which has a range of 180(!) to 220 and I printed with 195, was this maybe a to high temp setting? The other suspect I almost dare not ask, but could it be because of the Steel nozzle (TwinXClad micro-swiss)? Though I don't see how the noozle would explain the shift in the same filament.

Any help is much appreciated 😉

Napsal : 17/11/2017 8:12 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: Strange color problem

Rafael

You really could not have chosen worse colours to print together...

If you are slicing with Slic3r, you will need a huge purge tower and print at larger layer heights.

You could always try with KISS and variable purging...

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Napsal : 17/11/2017 9:25 pm
raphi
(@raphi)
Trusted Member
Topic starter answered:
Re: Strange color problem


You really could not have chosen worse colours to print together...

yeah I know but It looked so cool in my imagination 😀

I found the tower settings in slic3r and will toy around with them, but I won't print multicolor with the natural filament for the moment.

About the change in white filament, I think it has todo with the retraction when the printer moves from one part to the other which later it does not have to do anymore. So as long as two parts are printed the filament will cool a bit between each layer and won't cool anymore when it only has to print the pillar. Could this explain this?

Napsal : 17/11/2017 9:31 pm
louis.t2
(@louis-t2)
Active Member
Re: Strange color problem



You really could not have chosen worse colours to print together...

yeah I know but It looked so cool in my imagination 😀

I found the tower settings in slic3r and will toy around with them, but I won't print multicolor with the natural filament for the moment.

About the change in white filament, I think it has todo with the retraction when the printer moves from one part to the other which later it does not have to do anymore. So as long as two parts are printed the filament will cool a bit between each layer and won't cool anymore when it only has to print the pillar. Could this explain this?

I believe the slight change in colour on the natural PLA is the same of which occurs on transparent filament.
When printing with transparent filament on lets say, a tower, if the tool head has to move to another object it will allow it to cool that layer before the next causing heavier "frosting". Whereas printing it alone prevents this, creating a clearer final piece. This looks the same due to it becoming clearer after the other piece finished.

Hope this helps

Napsal : 18/11/2017 12:38 am
raphi
(@raphi)
Trusted Member
Topic starter answered:
Re: Strange color problem

Much more important than any settings is to design the model with multicolor in mind in the first place. I created a different model this time, again with the clear PLA, black, red, and blue and there's no color bleeding:

The solution was easy enough, I used to sink text by 2-4 layer into the surface on other models or all the way through to the bottom but this time I printed the text on the clear PLA instead of into it, red or blue were never on the same layer as the clear PLA (black is not a problem with clear). Has the additional advantage that no surface shells are created and the prusa handled the delicate text quite well I think, even with a steel nozzle at 0.15mm.

The backside looks like this:

So whenever you are printing something where you see the color only on the surface, print it only on the surface and keep the part beneath it in the same color, also saves a lot of printing time.

happy printing 😉
raphael

Napsal : 28/11/2017 9:04 pm
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