Nozzle scratches on bed/printed layers-.-

Hi,

I recently build myself a Delta Printer (i already haven ultimaker, was just curious to have another) which is printing almost fine, test cubes come out in right dimensions, z height is even all over the printing surface.

there's just one problem left that i couldn't solve: when the nozzle is leveled over the print surface with .1mm height (using a piece of paper) and then moves, i can hear the tip of the nozzle scratch on the printing surface. when the move is finished the paper test shows me that z height is still the same, the problem just occurs while moving. this causes the nozzle to scratch over the printed object, sometimes ruining the first layer, and over time "collecting" print material at the tip of the nozzle, whichs drips off when too much and causing an ugly "burned-looking" drop. sometimes the drop gets pushed away by the passing nozzle, sometimes the nozzle crashes into it an corruptes the next printing moves.

this behavour continues over the whole print, also at higher z values. height of finished prints is correct, so my steps/mm should be right. reducind material extrusion doesnt solve the problem, just causes "unconnected" lines when reduced too far, and the scratching problem remains.....

Still couldnt find a solution to this, after hours of trying i ended up that it must be something with the 3 carriages. something about their movement timing....? But no idea how to influence this.

So my question is: has anyone of you experienced such a thing or an idea what it could cause/solve?



Thanks,

eagreen