Dual Extruder for Pla

Hi everyone

I wanted to print a model in two color, I have a dual bowden mechanism and I'm printing with PLA.
I can print with each nozzle separately without any problem but when I want to use the dual extrusion, I have no success.
The problem is when the second nozzle starts to print, for some layers it won't print perfectly, I mean it won't fill the layers, but after a while, it will extrude normally.
Has anyone printed with dual nozzle perfectly with PLA?

Do you prime both nozzles before starting to print? One of the things that caught me out is that at the end of the print the idle nozzle is retracted by (in my case) 10mm, and my default skirt setting wasn't enough to compensate. Now I try and remember to bring both nozzles to the ready to print stage before each print.

If the problem happens on every nozzle change it's likely that you are losing too much filament to ooze. PLA can have quite low viscosity at higher temperatures so it leaks out of the idle nozzle quite fast. Slic3r (and probably others) have a setting for lowering the temperature of the idle nozzle to try and cut down on the amount of ooze. The bigger the temperature change you use the less ooze you should get, but the longer it takes to re-heat when you switch nozzles.

The use of a waste tower is the best practice when you are printing with dual nozzle. The tower will keep the nozzles clean and ready to print on any layer.

My problem seems to be like this:
When the second nozzle starts, the pla will flow from the nozzle because it's in liquid form. So I think the nozzle becomes empty for a while till the extruder extrudes enough filament to fill the gap?
So I think lowering the idle nozzle temp, is a good option, I'm using cura, Is there an option like this?

Quote
3ddreams
So I think lowering the idle nozzle temp, is a good option, I'm using cura, Is there an option like this?

Not that I can see, but Cura does have the wipe and prime tower. Hoepfully the 'prime' part of that will fix your problem.

I haven't tried it. I should try it. Thank you.

Edited 1 time(s). Last edit at 05/19/2016 01:43PM by 3ddreams.