Do i need to calibrate Z axis ?

I get this CONSTANTLY repeating waive pattern going up in Z axis.
This is about 8mm height so far but i would see it everywhere as if every X number of Z motors turn, something is changed.
Perhaps something is averaged out causing this to fluctuate ?

 

Another angle shows just that.
Its as if change takes place gradually and then goes back to normal and repeats.

 

Looks like z ribbing caused by the imperial rods, you can switch to metric rods or change your layer height. To one of these. 0.3mm layer height to 0.3034mm, 0.2mm layer height to 0.2046mm
Or if you want a different layer height you can use this calculator http://calculator.josefprusa.cz/ (scroll down) Select 5/16ths rod.

 

Can you point me to the correct rods on ebay ?
Thanks for detailed info and values.

 

You need M8 rods, there is a thread around here with more information.

 

You dont need them. You can get perfect prints with the rods you have. That's 100% without a doubt not your problem.

Belts too loose? Too tight? Incorrect values in repetier?

Btw its not problem with z axis even..its x and or y. The z axis looks right on the money.

 

The ribbing is in both X and Y direction, and it's constant, so chances are it's not belts.

 

Looks like belts to me. Belts are going to be constant and repeating.

Metric and imperial rods control up and down....not left, right, front back. If it was rods...only layer height would be the problem.

Using repetier? Robo version?

 

Here's some more info on z ribbing and what it looks like. On page 31 http://issuu.com/garyhodgson/docs/reprapmagazine_issue_1

 

That's apples to oranges. Tony is printing a straight up wall...not an egg. Z layer will not make a wall not straight...its not possible. Z layer will get funky on an egg shaped object...two totally different things. This is an x/y axis issue.

You can easily see z axis is correct by the uniform layers.

 

Ok what do i do to identify Z or XY issue ?
?

 

If its z...its a height issue. Print a cube. If the walls are wavy...its xy. If they are straight...print an egg. If its wavy and box wasnt its the z.

 

Try the belts first. It is a no hassle thing to use some plastic cable ties to add a bit of tension to the x belt and then take up a notch or two on the y. You don't want them so tight that it strains the stepper motors, but the belts should have some tension on them. Mine needed adjusting because of banding just as your pics show. Actually I did them both, then removed the x tensioner and just took two teeth up on the y which did indeed solve my particular problem.

 

In the middle of big print. Will do print tests and post.
Belt has metal tensioner.
Y is kinda loose but i see this problem all the way around as if layers slowly start to get mushed into the model more and more and more, and then back to normal and repeat.
If it was X or Y, it would be visible only in X or Y or both, not 360 degrees. thats just my thought.

 

My belts sound like a guitar string when plucked...but still move freely and not pulling motor shaft in.

Loose set screws will also do weird stuff like that too. If you haven't done anything weird in repetier...its the belts most likely.

 

Tony, your earlier prints were fine so this just started happening right?

 

no. always like that.
It goes to the left at the top because its modeled like that, but bottom must be straight..
Printing at 0.3

 

Front right side is nearly perfect.
Mostly mess is toward the back.


This image is at very slow print speed.
Checks out with 10.10 to 10.20mm
Height at 9.93 to 9.95 so i would need to adjust by z end stop to press earlier to make 1st layer more accurate.

 

I solved my z ribbing issues by adjusting my steps per mm value to a non-decimal value which rounds to the nearest half-step x 16 microsteps.​

​

I'm using 2264 microsteps per mm or 141.5 steps. The firmware takes microsteps, so use 2264 in the firmware and reflash.​

Once you flash the firmware this way, just use standard .1/.2/.3 layer heights instead of the funky ones that people have posted in the other threads that supposedly "compensate" for the imperial rounding issues.

 

easiest way to find out: print with another layer height. If its still the same: x,y belt or whatever problem
if its gone or different pattern: layer height.

then you can:
- take M8 rods
- changer layer height (http://calculator.josefprusa.cz/ for calculation scroll down and choose the imperial rod rod)
- change steps in the firmware as bob64 suggest.

to find out whats the problem, change the layer height, after that you can decide what's your favorite solution