Do i need to calibrate Z axis ?

Anyone in this thread that has experienced this ribbing issue, please respond to the poll Tessaract posted: http://forums.robo3dprinter.com/index.php?threads/waviness-or-not-that-is-the-question.2490/

 

I think that waves across the sides that are in the same pattern are Z issues with calculation of steps. I dont know how to fix that.
But the corners is not the X or Y issues, its the smooth rods on the X that are not exactly 8mm so it allows the extruder to wobble and make noise as it rattles.
Extruder's pivot point as at the back where its attached to the belt, so back side is always perfect and front is always wobbly on corners.
Acceleration does help, but it does not fix. It make sit wobble even more but then it does not stay long enough at the corners to make it more apparent.
When acceleration is low, as the extruder aproaches the turn, it slows down and speeds up after the turn.
It causes extra filament being extruded simply by gravity and the nature of PLA (not so much ABS). If you tweak acceleration to go faster (3500 default or faster) nozzle will go around the corner faster but it will also wobble harder when taking a turn.

Thats all i learned days of observation.

Now the question is:
Where do i get 8mm smooth rods (exactly 8mm)
and how to get that Z steps calculation correct (to fix constant waves on all sides) and not mess up the height of the model.


Thanks !

 

I have these:
http://store.makerstoolworks.com/motion/precision-linear-shafting-8-mm-x-445-mm-set-of-2/

These guys also have various sizes in their store. I have gotten other parts from them and they ship fast.
http://www.ebay.com/itm/8mm-x-1-met...Rostock-Prusa-3D-printer-CNC-O1-/331047793540

 

Ziggy found that the largest contributions to Z ribbing are the stepper/rod couplers and stepper disable. See his document on Z ribbing for the suggested solutions. The coupler fix is simple and only requires a 3mm bike ball bearing. Also if one of your threaded rods is obviously bent or a coupler is bent you need to swap them out.

Unless you change your threaded rod pitch you don't want to change the Z steps constant in Marlin.

 

How long do they need to be, 445mm or what ? Caz thats what one sells and another sells 1 meter of that that wold need to be cut.

 

You should be able to cut them with a hack saw or a grinder. Just be careful how you clamp them so they don't get scratched. Now I have not cut my chromed rods yet but I have cut other types with no difficulty.

 

After i upgraded my bed with my own (highly modified Y-Upgrade Printable kit) i noticed that waves went away.
See my thingiverse link below for this upgrade.
Woo-Hoo !


I'll need to tighten my X belt after year of printing to make it even better.

 

Tony, did you do the firmware modes for holding the Z steppers that Ziggy outlined? How about the 3mm ball bearings in the couplers?

Those side walls look great!

 

I did everything. I did the firmware trick and inserted a ball bearing into at the bottom of the Z rod just like in the instructions (some topic i read here somewhere) but none of that had even a slightest effect.
It was the bed on rails, dont know why.
Once i upgraded to smoothrods, not only it fixed the problem, but my design gave me 270mm on Y instead of 255mm
I could push it above 280 but i would need metal bearing housing and perhaps 3rd bearing on each side for more stability.
The more build area i create the less stable it became because of plastic nature of business. If it was metal it would be awesome.
Maybe 1 2 times longer bearing ? I would be able to get close to 300mm on that bed