Belt wear/damage


#1

All,
I want to add this post in hopes that it helps up-and-coming FarmBot-its avoid a pitfall I think I fell into…
In the early days of setup, I think that I installed and tested the belts in a manner that led to some damage that is having impact to this day.
The story:
Soon after installing the FarmBot, I was eager to “kick the tires”. I fired up the robot and was soon sending commands to “move here”, “move there”, “move everywhere”. At this point I observed that FarmBot was having problems. It would stall, skip, make funny clicking noises, not do what I had told it to do.
After much observation, conversation, adjustment, tweaks and a bit of grease (both white lithium & elbow) I was able to get the FarmBot to move as instructed. However, in the early days, with all the slipping, the X-axis drive belts took some damage. (see vid clip at:

Just in case the link does not work in the forum, try cut-n-pasting this:
https://www.dropbox.com/s/1vonnunnxxmm8ez/IMG_1563.MOV?dl=0”

I was able to do a short-term fix by moving the damaged portions to the far end (from “FarmBot Home”), thereby allowing us to seed & water the front 3/4ths of the planter bed.
I believe the only true fix at this point is to replace the belts… :frowning:
If I had to do it again, I would be VERY careful of applying tension, strain, and torque to the drive belt system until I fully understood (and appreciated) the physics and dynamics of the drive system. I would start with everything looser & better aligned. I would only perform very short tests. (I had a few “just let the motors run and see if it “powers on through”” moments that I really regret).
I hope this post saves at least one, if not more, folks from the same experience (a $140 lesson - the cost of two new X-axis belts)


#2

Hey @Intelbotfarmer, thanks for the detailed write up and video. I’ve never seen any belts chewed up like that. It is hard to tell from the video, but did you apply some type of grease or lubricant to the belts? If so, that may have reacted with the belt material and caused it to start degrading rapidly.

Adding a reasonable amount of tension to the belts should have had such adverse effects. The worst that happens that I’ve seen from too much tension is the motor will simply not want to rotate. It would just just buzz in place.

If anyone is considering it: do not apply lubricant of any kind to the belts or pulleys. Not only could it possibly react poorly with the belt material, causing rapid failure, but it is unlikely to solve any movement issues. In fact, I could see it causing more issues, where the belt teeth slip in the pulley’s teeth due to a lack of friction. I’m going to add a warning note about this into the official documentation.


#3

Thanks!
No, I did not apply any type of lubricant to the belts at all - I get why that would be bad.
I think what happened is a combination of too much tension and mis-aligned rails. This caused the belt to ride to the side of the V-wheel and get pinched between the wheel and rail.
I am ordering new belts now, lesson learned.


#4

And V-wheels too tight…
I think I created the perfect storm…


#5

I might sugest that in your add, maybe include some pre-power on verification.
Something like:

  1. Once the structure is assembled, move it slowly down the length of the tracks.
    a) Have a friend help by moving the opposite side at the same time.
    b) Observe the following locations:
    i) Each pully - Does the belt stay centered? Is it too loose or too tight? Is there a small gap between the pully and the housing?
    ii) At the location where the belts transition from the gantry supports to the tracks - Is the belt centered on the V-Wheels? Is the belt touching the tracks?
    iii) Observe the belt - Does the belt lay centered in the track for the entire length of the rail?
    c) Look down the length of the rail - Is the rail perfectly straight? (Up & down, left & right) shimm if needed.
    d) With your friend, slowly move the structure. If you encounter (feel) any resistance, stop and investigate. Do not go on until you understand and resolve the resistance. (Shimm, adjust V-Wheels, adjust belt tension, lightly sand track section trasitions until they feel smooth, remove dead slug, etc…)

Hope that helps!