6040 finally packed in!

[KevinC]

I have been running the eBay 6040 for 4 months now and it has finally developed a major problem.

My x-axis is jamming up when it gets near the middle of the axis. It causes the whole gantry to jump as it passes across this area and results in a jagged finish on the work piece which is unusable.
It only happens when travelling in one direction - pulling towards the stepper (as opposed to pushing away).
It seems to happen at slightly different points along the axis each time I try to recreate the problem so hopefully it's fixable.
I would guess that it has got dust inside the bearing. I may have caused this by applying spray grease to the ball screw several weeks ago.
I am tempted to strip it down and clean everything but this will be a big job that is a bit out of my league.
Any advice would be greatly appreciated.

Thanks,
Kevin.

[mekanik]

Hi Kevin
Sorry to hear about you problem.
Try spraying with WD40 and running the gantry back & forward full travel, clean ballscrew exterior and repeat, with a bit of luck that might clear the grease and associated dirt, don't have a machine myself so not sure if it's supposed to be oiled or greased.
Hopefully someone with more experience will be along with some more info
Regards
Mike

[KevinC]

Hi mekanik,
Thanks for your advice.

I have just discovered a broken bush on the x-axis.

This is obviously the cause of my problems.

I am very happy that this is a simple fix. The thought of stripping this down is a daunting one!

I can't wait to get my new machine from Dean - JazzCNC! It looks like a fantastic machine!

Thanks again,
Kevin.

[KevinC]

Here is the broken part. I thought it was called a bush but I'm having no luck finding it on eBay when I search for 'CNC bush' which leads me to believe that it's not a bush! Lol
Any idea what it's proper name is?

Buy right or buy twice as they say!

[mekanik]

Hi Kevin
Glad you found the problem.
What your looking for is a flexible coupling.
http://www.ebay.co.uk/itm/Flexible-S...item4aee96e3d9
Dean's Machine will be a cracker.
Regards
Mike

[KevinC]

Thanks again Mike,

Would these work the same as mine?

I notice they don't have the slit/hinge running along the width like mine.

Let me know if you ever need something cut Mike, I owe you one!

Cheers,
Kevin.

[mekanik]

Hi Kevin
That's a very kind offer.
The coupling in the link locates and is locked with a grub screw, yours just has a different clamping arrangement so it will be fine.
Your coupling will have sheared for a reason, what you need to do is check that the gantry isn't binding for a start, but i would suspect it's probably a slight misalignment of the motor and ballscrew shafts causing the coupling to flex on each rotation and eventually metal fatigue results in a break.
While your waiting for your coupling try and align the two shafts as best you can, if possible shim the motor to suite.
Good luck
Mike
PS
or what Lee said

[Lee Roberts]

They should be fine as a direct replacement, however I see allot of this flexable type brake in this way, so I would advise going with a "lovejoy" or even better an "Oldham" type coupling.

.Me

[KevinC]

Thanks Lee,

I just purchased the flexible type recommended by Mike.

I will have a closer look at the Lovejoy & Oldham couplings now.

I can't wait to see the back of this 6040 toy!

The Dean-Machine will be a most welcome upgrade!

[KevinC]

Thanks again Mike,

That makes sense.

I will try to get them aligned as best I can but I honestly wouldn't know how to go about this.

I guess I'd need one of those gismos for super fine measurements. I don't have one but I've seen them used in a few youtube videos.

Kevin.