Printing quality with UM3 Extented - Dual Color

[Welveryn 2]

Dear all,

 

I had the chance to fix an UM3 and get it for free. After printing some pieces with one extruder with good quality (see grey 3D benchy); I was interesting in printing with the second nozzle!

 

From my point of view, the rest of 2 years old PVA was not usable because, it always do some "cracks" noise when printing and very poor quality.

Also I was interesting in printing with the second nozzle, with an Printcore AA 0.4; So I installed it, etc.

 

For the test I chose the 3D benchy bi-color. I merged the model, etc...

 

And what was my surprise when it has finished the print process...I admit that the result is so bad...

 

I am really new, it's my first time with bi-color. I assume that I don't really know what I am doing wrong.

 

The printer is newly on a desk as you can see in the picture, is it possible to lead more vibration ?

The slicer does not perform a good job because of my unexperience ? 

Something went wrong with the rear spring ? (never changed it since 2017)

Other ideas coming from expert ? 

 

If you have any questions, remarks, etc, please feel free to ask ! I would like to take all advices.

 

Thanks in advance for your answers.