Z axis Belt - Tension (am I doing this right?)

[edh]

Hey All,

Started assembling my CNC yesterday, and got through all the main assemblies - mostly OK. I was missing some hardware (m5 x16mm) but a trip to home depot fixed that.

I'm now putting my Z plate on, and have several issues / concerns. I would love to hear thoughts and suggestions.

1. I have a lot of slack in the belt, it is loose enough that it twists and seems like it wall fall off the idler bearing in use. This is with the motor and tensioner as "tight" as they go.

2. I had to install the fixed gear on the z plate backwards (set screws closest to plate) from what the diagram shows, otherwise there was just to much of an angle between the motor, fixed gear, and bearings. I tried moving the pully on the motor up and down to align it better, but the bearings at the bottom were still at an angle. Inverting the fixed gear from the diagram seems to line things up nicely, but I'm concerned about this.

Below are some pics, please let me know if you need anything else. Hoping to finish the machine up today, but don't want to proceed until I sort this out.

Thanks!

Is this Right?
https://www.dropbox.com/s/6gt6gl6zxtuf9 ... 0.jpg?dl=0

Here is the slack (there is no force on the screwdriver, just using it to show the belt slack)
https://www.dropbox.com/s/iacs968zdmjra ... 9.jpg?dl=0

[WillAdams]

Since the belt doesn’t move at the attachment point to the spindle carriage, one could in theory tighten that adjustment point so that the belt is trapped — try that?

If that doesn’t help, you probably have the wrong belt — I think GT2 may be used in some automotive applications — but contact support@carbide3d.com and they’ll set you (and me?) straight and set this right.

[edh]

Hey Will -

Thanks for the quick response. Trapping the belt might work, but it seems unfortunate to have to do that on a brand new machine / belt. The part# on my belt is 524-2GT-6 - I'm wondering if I have the right one?

The Z-axis pulley is supposed to be reversed from the other motors.

I believe this is for the X-axis pulley, not the Z.

Either way, I'm not referring to pulley on any of the motors. I inverted the fixed pulley (part #6 on Assembly 4 - Z-axis carriage plate) to get the alignment better.

Thanks again, Will.

[WillAdams]

Belt should be correct:

23 1 S3074 GT2 Profile - 524mm Endless Belting

Hard to see how it could be out of spec --- something wrong w/ the plate?

Try adjusting the other parts --- loosen them so that they pull the belt more and tighten them?

[DannyBoyNYC]

edh - were you able to resolve this? I am experiencing a similar issue.

[edh]

edh - were you able to resolve this? I am experiencing a similar issue.

Hey Danny -

Still no luck. I also found out my Z motor was bad (it only turns in one direction) - so I'm not sure if that has anything to do with the issue or not (seems unlikely).

At this point I'm waiting on a new belt and motor from Shapeoko - I'll update here when I get them. (In fact I'm going to go ask for a tracking number now).

-Ed

[LTEPM]

Maybe @Edward or @WillAdams can chime in here, I could not tighten the Z axis belt when I had it on the static pulley engaged with the teeth. I moved the belt to the collar (smooth) and was able to tension the belt properly. It also is inline with the other pulley, bearing, and tracks well.

[WillAdams]

I'm not getting what you're saying at all --- could you post a photo or a diagram?

I'm thinking that I'm going to have to draw up at least the Z-axis in order to wrap my mind around it --- I'm just not getting it.

[muskett50]

I am also experiencing this problem with a very slack belt. on the z axis. The belt i have is 524-2GT-6 . Has anyone come up with a solution for this?

Thank you
Muskett50

[WillAdams]

I am also experiencing this problem with a very slack belt. on the z axis. The belt i have is 524-2GT-6 . Has anyone come up with a solution for this?

If you still have difficulties, contact support@carbide3d.com.