Flashforge Creator Dual / Pro How to fix Dual Extruders dragging across prints.

[FrankV]

This thread is an interesting read but I get slight scraping from either extruder when the other is printing. This suggested a different cause than head and bed levelling. First thing I found was that too much plastic was being extruded - printing a cube with 100% infill delivered a domed top. Having sorted this the problem is less severe but still there. Even the same head will scrape its own layer if it happens to go back over it before the next layer starts. Could it be that I am not setting enough gap between the heads and the platform during levelling, so the plastic is squeezing up around the nozzle? I use a sheet of 80gsm paper, 0.1mm thick, adjusting so the paper just drags but without folding up when pushed. Both nozzles seem to excerpt the same drag once the bed is levelled.

Any suggestions would be appreciated.

In an ideal world, the head should be able to be retracted vertically by a small amount when not in use. Thinking about reducing the heavy head mass by switching to a Bowden cable solution, perhaps I can think of a clever way to incorporate a small up/down mechanism. Even wondering if having a sprung head with 0.5mm restricted travel and using the extruder pressure to force the head down could work - probably create more problems somehow!