Rubberband against rattling Traxxas rod ends

We had a discussion about reducing slack in Traxxas driven effectors. Can't remember the headline...

Now with my new delta, I was able to test my idea ( based on Nebbians? suggestion ).

It works pretty well, even the deviation shown after a RRF auto bed leveling is much lower. ( was 0.04ish, now 0.014 )
Surprisingly the rubbers don't move much on the rods, but I'll print some clamping stuff to fix the rubber in position.
The keyring acts as a filament guide and can be modified to host a filament cleaning cloth, too.

Only issue was the stepper current: I had to raise it a bit,, but TBH it was pretty low in the beginning.

-Olaf

I have the extruder drive mounted just under half way up one of the towers. When I was using Traxxas rod ends on my delta, I observed that the sideways force exerted by the Bowden tube changes direction depending in XY position, causing the play in some of the joints to be taken up in opposite directions. I did two things to counter this:

1. Rotated the rods end-to-end where necessary to get all the loose joints at the effector end, and then added springs across each pair of rods near the effector to take up the free play. I used zip ties to prevent the springs sliding up the rods..

2. Added a piece of elastic from the Bowden tube to the top frame, to help take its weight and reduce the sideways force.

These changes reduces the calibration deviation by about half. Much of the remainder turned out to be caused by having the wrong number of washers between one of the wheels and the carriage, which caused the carriage to be twisted slightly about the Z axis.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Simple and effective, I like it! It also locates the filament nicely.


The only problem I've found with rubber bands is that they perish after a few months due to UV light. I've moved to springs on my flying extruders for this reason.

I think the topic you seek is this one:
[forums.reprap.org]

Edited 1 time(s). Last edit at 08/04/2016 04:04AM by nebbian.

I'm using springs too: [www.thingiverse.com]
Rubber bands break every few weeks.

Thanks Nebbian for pointing me to the old thread.
You are right about the rubber vs. springs issue, but I found the right springs are harder to find and the ballpen springs I initially had in mind wouldn't fit the bill.

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roboprint
I'm using springs too: [www.thingiverse.com]
Rubber bands break every few weeks.

Those clips look tiny and might brake too eventually. Did you consider placing them at mid rod height? Or do you have two springs at top/bottom of the rods?
I'd probably design a closed clip or use a tie rap instead. ( ugly )

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o_lampe
Those clips look tiny and might brake too eventually. Did you consider placing them at mid rod height?

This is my own design, working great for about one year on my Kossel Mini. Printed using ABS (PLA will break after few hours). Very small and light. As for position near effector - I moved weakest traxxas ends to effector side, so it's enough for me.