When printing in clone mode one object shows a z-wobble like effect a lot more than the other. Any idea why this can happen?
http://b.bonkers.de/?p=252
What’s your extruder temp doing? Temperature swings due to bad PID tuning can do this.
Temperature is very stable that is not the problem. So far it seems i made a mistake when reassembling the machine a couple of days ago.
@Nathan_Walkner with dual x carriage you can use clone mode to print two identical objects in one go
@Nathan_Walkner The z rod is very straight and under pulling load. It seems the lower left bearing wasn’t correctly aligned, after realigning it the result is much better, but not perfect yet.
I replaced my Z Nut holder with one made from Ninjaflex. There is definitly no chance any slight sideway movement of the rod can be transfered to the printhead now.
When i saw that the wobble still showed (right side of the image) i tried to push the X bridge in a way a bend rod would do, only MUCH harder. As you can see it shows in the print, but the interesting part is that the wobble is still overlayed. I am out of ideas right now 
https://drive.google.com/file/d/0By5RP0qeDY-5RXZfWmRBeWFmaHM/view?usp=sharing
Sher
It seems that the white material is much more susceptible to whatever happens. I printed two identical pillars with the same gcode, same extruder etc. th eonly difference was the material. Lo and behold, the blue part does show the effect but the surface was much smoother than on the white one.
Hi. I have the same experiance as Björn. Use the same type of plastic from the same vendor. One color prints perfectly, another color shows a more bad result. Must be the color chemicals added to the plastic.
@Torben_Vandborg For me the problem is that i have no idea why it is so regular. The latest proposed cause is that the nut i use is somehow malformed so i don’t get even movement.
I don’t know the source yet, but i do indeed get uneven Movement along Z
http://b.bonkers.de/wp-content/uploads/2016/02/Zdiffperstep.png