Z Axis - precision and accuracy

I think we need someone to do the rotation test on just the steppers to eliminate the whole friction throwing the steps off.

 

Here's a stupid question... If you disable the disabling in the firmware and then start a new print, will you be able to adjust the z-axes during the skirt to fine tune?

 

Sorry, I meant reaching into the printer and turning the threaded rods by hand but using the manual arrows in Repetier would work too.

 

http://www.omc-stepperonline.com/ne...rew-nut-unipolar-300mm-t8mm-2mmrev-p-230.html

Donhuevo, i think this one from that site that would be interesting.
8mm thread and antibacklash nut, 2mm/rev. This would give 0.01mm per step.
No couplers though, so need some care in the install to prevent side force etc.

 

I ordered two of these last night...
http://www.omc-stepperonline.com/th...ody-300mm-lead-screw-t635mm-2mmrev-p-225.html

I thought about that other one though. It was the only one w/ 8mm rods and 2mm/rev. I'm actually excited about being coupler-free. That may have come out wrong.

 

Donhuevo, the rods are locked as soon as you start the print. So no adjustments. I found it was good to break me of that habbit anyway.

 

That habit of desperately twiddling rods and hoping the first layer mess will come good? hehe

Cool Donhuevo. Hopefully, Z-axis will dial in well enough (and with the anti-backlash nuts etc) that all the fussing with paper spacers and z tweaking will be reduced or eliminated.

The worst part of prints is always the start. lol.

I'm pretty pleased with my first print today though, my first print after the E3d and LCD upgrade, plus my new vertical rod holders were installed. pretty clean sides, just a basic cylinder, but a good literally 'first' print after alot of mods.


The 'rougher' end view is the bottom.

These are my new CNC machined z rod holders.


Next print is my top mount spool holder.

 

where did you set those smoothed rod holders?

 

Designed them and had them cnc machined from billet in China. Even so, they were expensive. But they are a prototype. If I make more they will be a bit cheaper as they dont need to have so many threaded holes etc.

They are so solid though, the vertical rods feel great.

 

Those are very impressive. You could get by without having a switch mount with the autolevel switches.

 

Ive been meaning to read up on the autolevel improvements.
How do you think it could integrate?

 

Check here: http://forums.robo3dprinter.com/index.php?threads/robo3d-autolevel-via-mike-kelly.2574/

 

This is definitely going to come out wrong but I got good at twiddling. I'm all dialed in before the skirt is up. That sounds even worse but you get what I mean.

 

Thanks ziggy we appreciate the time that you are putting into this issue. I hope the robo team is helping you out.

 

I had a bad coupler out of the box, so yes i replaced one, it was bent so bad that the threaded rod swung around pretty wildly.
What is the implication of having disassembled the rods? Prior to my major list of upgrades (and before i removed the bad coupler) my z ribbing was 10x more awful.

Somewhere to pay a bit of attention during the teardown, the holes in the base plate for the z-rod nema motor screws are wayyyy oversised, like almost m4 clearance hole for an m3 screw. Presuming that the cnc cut base plate of our printer is infact 'true to drawing', (which i'll be bold enough to assume) and the x carriage is assembled accurately from molded and accurately cut parts.....
I think bad motor alignment is a major issue, especially since the assembly quality from the factory was a little dubious.

I want to find some thin wall plastic tube/straw and 'shim-out' the nema motor screws so they are centered and concentric. If you look at the bottom of my printer you can see that the nemas are a few degrees out of square.

Nice work on the testing.

I'm going to go twiddle some x-rod right now!