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-   -   Drive tension spring too tight? (http://www.mechmate.com/forums/showthread.php?t=3580)

smreish Wed 16 November 2011 19:11

Drive tension spring too tight?
 
Recently a thread discussed using rubber bands, zip ties or what ever else to tension the MechMate drive motors to the rack. This had me think that "what if it's too tight" ? What if the motors have too much direct tooth pressure and not enough movement within the engagement to "find a comfortable mesh".

I visited a machine locally that had begun to show signs of chatter and restriction of movement on the x/y change during curve and circle cutting. This is usually the sign of the everything beginning to loosen up. A grub screw, a bearing hold-down, a motor pivot shaft - something. This machine was what appeared perfect.

What I found was the machine, over time, actually tightened up some, and was restricting the gentle (built in the design) anti-backlash performance of the machine. What we found was that the too tight spring, the slightly tight adjustment bolt/nut on the swing plate and the slightly to snug motor pivot point caused the machine to make noise, shutter on transition and expose inaccuracies.

Moral of the story....sometimes loose is good.

Kobus_Joubert Wed 16 November 2011 22:49

Like a happy tappet on a V-8 :D

sailfl Sat 19 November 2011 04:39

It was my machine and the difference in springs and removing the plastic washers helped in the performance of my machine.

Thanks again Sean.

IamDave Mon 05 March 2018 12:42

I think I just experienced this. Springs to tight cause chattering and racking.

ifffff Fri 09 March 2018 13:20

Well.... intresting. I have on my MM drive tension springs taken from car drum brake pads. And for installing installing them i need lock pliers and lots of force. And i changed weaker springs for them because of chattering...

IamDave Fri 09 March 2018 17:29

I loosened my springs and it helped greatly with the racking problem. My speed setting was way to high as well. Now it moves smoothly.


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