Printing problems caused by the Z axis shaft connector
#1
I have Tevo Tornado for 3 months. All my prints has ugly horizontal lines.
I tried everyting (slicer programs, extruder settings, filaments) but nothing helped.
The problem was the Z axis connector next to the Z axis motor. Tevo missed the lower axial support bearing and this connector has to support all the axial forces. This type of axial connectors has a spring effect and the Z lead screw can move up and down a few millimeters.
This is a basic mistake in the design.
It has two solutions:
- the first - what i tried - is very homemade but fast:
Use some "Glass fibre reinforced self-adhesive tape"
It solved the problem in seconds, no more lines and bumps.
- the final solution is to add an axial bearing to this shaft which should have been factory-ready...

On the pictures the black prints are before, the yellow is after my little modification, check the difference.


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#2
Hiya,
just stumbled upon this problem too.
Cant imagine it helps if you just wrap some tape around the shaft clutch ?
Or did i miss something.

I thought about a pressure plate on top of the spindle. Which may eliminate the backlash.
Where to put a bearing ? under the shaft connector (clutch) im confused.

thx for ur effort
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#3
(03-07-2018, 10:19 AM)PepeD. Wrote: Hiya,
just stumbled upon this problem too.
Cant imagine it helps if you just wrap some tape around the shaft clutch ?
Or did i miss something.

I thought about a pressure plate on top of the spindle. Which may eliminate the backlash.
Where to put a bearing ? under the shaft connector (clutch) im confused.

thx for ur effort

The tape is not the perfect solution, just a try. It just helped to identify the problem but not perfect.

The pressure plate is a good idea.
On the lower end of the spindle is not enough room for a correct bearing and its housing. The upper end is better (however the perfect solution is to place bearings at both side). I just looking for a bearing for this, that is what i found:

KFL08 It has two grub screw to fix the shaft and and it may has enought support for the axial forces.
Another useful thing what i found: Spring Loaded Nut

This would be an easy solution. I'll try it and will write my experience here.
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#4
yea, just found out the clutch wasn´t solid..explains the backlash Wink

i wrap some tape now for a start.

Have you already adjusted the stepper motor voltage ? ..makes a huge difference in layer smoothness too.
https://www.youtube.com/watch?time_conti...kjwOxDSCiQ

take a look..its worth doing it Wink

cheers
PP
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#5
Did you see this solution to your problem:
https://www.thingiverse.com/thing:2827664
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