Cross layer gradient

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Plantdood
Posts: 2
Joined: Tue Jul 21, 2020 10:26 pm

Cross layer gradient

Post by Plantdood » Mon Aug 03, 2020 5:14 am

Hi all,

Ok so the color mixer software isn't working for me but I think that might be an issues with the way the new version of Simplify3D works when it creates the G-code, not sure yet but either way I can't use it, so I have been using the mixer setting on the LCD.
Now I'm not sure this is supposed to be even possible but I'm getting Cross layer gradient, one side of the print is grey and the other is black, all in one layer and it doesn't matter the size of the part.
I don't even want a gradient, I just want to mix black and white PLA to get a version of grey.
I dropped $180 on Simplify3D so I'll have to work around it since it has no gradient mixing options and hopefully I can get the mixer software to work but WTF is going on with the mixing?
The printer works great beyond that, the dimensional accuracy is spot on and when using a single filament the finish at 0.1 is amazing, no need for sanding or chemical smoothing.
Everything is wired up correctly, E0 on the right, E1 on the left, run out detectors don't work though, have the newer or cheaper non ball mount ones, they just don't work.
It has been doing it from day on though, as you can see on the Geeetech test print dog it tries to start out lighter at the bottom and darken as it goes up but the dogs chest ends up being light while it's back is completely black and than as it gets to the head the gradient levels out to completely black.

Like I said I'm not sure this is currently supposed to be possible on a mixing extruder, getting a gradient in the X or Y axis.
Should I just give up and donate this thing to science? Are we entering a new frontier here?
Anyone got any tips on making the mixing software work with the latest Simplify3D?

Cheers.
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BadShep
Posts: 2
Joined: Wed Apr 01, 2020 4:52 am

Re: Cross layer gradient

Post by BadShep » Tue Aug 04, 2020 7:38 pm

I bought this printer on the similar assumption as you, where if I use cyan, magenta and yellow filament I can get any color. Unfortunately that isn't the case due to the design of the nozzle. The t(m) series printers are good for 3(2) individual colors and doing transitions over layers similar to what you are seeing. They are not good at mixing certain colors to get a new one like you wanted. This is due to the toothpaste effect. What you are seeing is known as the toothpaste effect where the plastics stay on the side of the nozzle they were fed into and don't actually mix together. If you look the black side of the print will be nearest to where the black filament is fed in to the nozzle and the white side is nearest to where the white feeds in. There is one thing you can do to mitigate this, however it won't completely disappear in this printer due to the nozzle design.

1. Use transparent filament ie transparent color pla or transparent color PETG (https://www.amazon.com/YOYI-Filament-Di ... 896&sr=8-3). There are several options available online. Due to being partially see through the filament in the back is more visible and looks like it is the proper mixed color.

If you want to replace the print head, then getting a nozzle with a much smaller mixing chamber will increase the mixing, or getting a nozzle that is actively mixed will do what you want. I do not know of any active mixing nozzles on the market. Try using transparent petg and see what you think.

Plantdood
Posts: 2
Joined: Tue Jul 21, 2020 10:26 pm

Re: Cross layer gradient

Post by Plantdood » Fri Aug 07, 2020 6:14 am

Ah yes thanks BadShep, a toothpaste effect makes sense, thought it might have been my cheap PLA but didn't matter which one I used, never tried mixing with my TPU, would probably have a similar outcome to the PETG mixing.
Bummer :( nothing a bit of airbrushing won't fix I guess.
Cheers.

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