M2 Dual extruder rotates in the belt mount (in the z-plane)

[chuck]

hi all,
upgraded at the weekend from the V3B. two problems, one critical:

1. (not critical) the printed part that fits around the two extruder motor wires doesn't fit very well at all over the motors
2. (critical) after a couple of prints, the whole dual print head seems to rotate about the mount on the belt, so that the filament doesn't feed cleanly into the extruder (to date i am only using the left extruder). if i grip the assembly i can actually twist it back into position. but this is not good.

for 2. - is there any way i can tighten the assembly so that it doesn't rotate without disassembling it from the belt mount? surely someone has thought of this...

fingers crossed someone can help. i prefer otherwise the v4 infinitely to its predecessors, it is much better in respect of adjustment of the extruder height.

Chuck!

[Jules]

If it's rotating at all, you don't have something seated or tightened correctly.

An area where i first had trouble when I assembled it was getting the filament drives to fit flush against the motors. They have to completely surround the little raised metal face on the motors and sit tightly against the main body of the motors. But in order to make that happen, I had to go back to the step for the Mounting Plate Assembly on Page three and start over from there. You have to press that plate all the way back against the frame before tightening the screws, to make sure you have the holes aligned correctly.

(Obviously you don't need to do the whole re-wiring part, just realign the motors.) If that's not the problem, post a couple of close up shots of the area in question. It's the only thing i can think of that might shift, if it's not seated correctly.

[chuck]

Jules,
thanks for this really thorough advice. i thought i had a different problem to the one you tried to help me with (it was rotating in the x plane) but your explanation helped me to take a different look at how the heads were screwed in, and led me to the discovery that the bolt down between the motors was as fault. this was (i hope ) all i needed, as the extruders are now much more robust, and i did not even need to take anything apart, as the screwdriver gets right in there to tighten it up.

thanks a lot though, you are providing some dynamite support for us here!
Charles

[Jules]

Fantastic! (If i've gotta be wrong, at least it's in a helpful way. )