I am trying to use a 3D850 PLA filament which is supposed to work without any issues with any PLA printer. As a printer, I use Dagoma NEVA which is supposed to work with any PLA filament. I can print with the filament without any issue, but I encounter a problem when I need to swap the filament. Somehow 3D850 sticks within the nozzle and even when it's heated I have to push really hard with another filament to push the current filament out (usually when the nozzle is heated up I can just easily push a filament inside for it to come out of the nozzle).
Is there any special behavior of 3D850 that may cause it to stick inside of the nozzle?
My guess is that particular brand of PLA is changing state inside the nozzle as it cools. Quoting from the manufacturer's page,
Materio3D PLA uses the NatureWorks Ingeo 3D850 polymer, specially engineered for 3D printing. It is tougher and stronger than standard PLA and can be annealed for improved heat resistance and toughness!
If the residual material in the nozzle cools slowly enough (at the end of a print) to anneal, then by design it won't re-melt at the same temperature as the raw filament material. I would recommend changing your gcode so that the extruder hotend is held at temperature after a print completes, and making sure to clear the nozzle with an alternate type of filament before allowing the nozzle to cool.
quoting from another page,
To achieve a heat treat on a printed part, submerge in water (or bake in oven) at 200F for up to 30 minutes.
notice that's Fahrenheit, well below extruder temperatures.