Unidentified "grinding" noise - SO3 XXL Zplus

CNC Machines Shapeoko
1

Hi All,

I’ve owned a SO3 XXL for almost a year now, and suddenly it started to make a grinding noise in specific situations.
Initially I thought it was some kind of damage on the bearings on the makita router.
Then I realized its specific to a range of rpm on the router (somewhere between 16 to 20k rpm),
and that made me think that might be some lose part on the z plus carriage of the shapeoko vibrating to a specific rpm of the makita.

My line of thought was that if it was the bearings it would make the noise all the time and with increased speeds would be worst. I then removed the bit out of the router and the noise stopped, no matter the rpm, there is no noise. Also, if i remove the router from the shapeoko “clamp” it makes no noise, with or without bit attached, and no matter the rpm. That turned me to the shapeoko carriage again. Disassembled the part that holds the router and checked for any lose screws in all the parts that are accessible without disassembling the entire carriage. Found nothing worth mentioning and assembled the whole thing.

Then i noticed that if I hold the Z lead screw motor while the router is making the noise, that it stops the noise, and by holding i mean just gently wrap my hand around it, don’t need to apply a lot of pressure/strength. That confused me a lot, but i was in the middle of cutting a guitar neck and i dint want to trash the blank,so I decided to shift the rpm out of the spot where it makes the noise and finish cut. I changed bits 3 times during the process from 1/8" bit to 1/4" and nothing weird happened, it went through the cuts with no noise or any issues.

The last operation on this side was the indexing holes for the flip, and it had to cut 30mm of maple and 10mm of MDF, and it went normally through the maple but when it go to the mdf (Z axis went to the most negative position of all of the cuts) it started making the same noise but in a way that i thought i was somehow cutting through the washers that hold my waste board. Was not that, so it made me believe that the Z axis being the lower it has ever been had something to do with the issue.
Also when it first started doing the noise i noticed if i moved the Z axis (router running) down and the
volume of the noise increased.

I’m absolutely lost now, as i don’t know what else can I do to understand if it is the router or something in the shapeoko.

Here’s a video of the noise it does and it stopping when i shift the rpm on the router or wrap my hand around the z motor (Noise warning).

VID_20210527_164756.mp4 on Vimeo

Hope someone can provide any kind of help.

Sorry for the wall of text.

Thank you.

Hugo.

2

Hi Hugo,

From what you describe + that video, I tend to think it’s the router.
If you fast-jog the machine around with the router turned off, do you hear any suspicious mechanical noise?
Roughly how many hours of use do you think you have on it ?

If its bearings start to go bad (which is not unheard of as it ages, but one year is still a short time), you can get subtle new modes of vibration, and then this small extra vibration can make whatever the router is mounted on resonate. The thing with resonance is that it has frequencies where the effect is amplified, and other frequencies where the effects are dampened. By removing the router from the mount, putting your hand on it, putting your hand on the motor, you add some level of damping to the overall assembly, which can be enough to make the offending vibration frequency disappear (and the noise with it). Same with changing the RPM, it alters the frequency of vibration, which is enough to make the noise appear or disappear (similarly for chatter, sometimes just changing the RPM slightly will make it disappear). And it’s not a simple as “more RPM, more vibration”, quite the opposite sometimes.

You may contact support@carbide3d.com about this problem, in case they have additional guidance.

Also, check the brushes in the router (removing the black caps at the top of the router), they may be all worn out after a year of use, and this could add to the problem is the electrical connection to the rotor is not consistent over time.

1 Like
3

Hi Julien,

No noise at all if the router is off.
Although i have it for a year I haven’t used it that much as I’m in the design/prototyping part of it.
I’d say like 20 - 30 hours max.
The router is still under warranty, but I see myself having a hard time explaining this to the shop as
it doesn’t make any noise when its not attached to the CNC.

I’ll check the brushes and will give it a go at trying to get the brand to check it.

Thanks for your reply.

4

Just an a thought, I remember having a DC motor driving a hydraulic pump that made a noise similar to the noise in your video, it turned out to be a sticking brush. Carbon dust from the brush had worked its way down between the brush and the brush holder causing the brush to stick in the holder and not make solid contact with the commutator bars on the armature. As a result motor rpm fluctuated rapidly causing a vibration in the sheet metal enclosure. Eventually the motor just stopped running and the problem was found.

Do you think the router rpm is steady and smooth?

Also, does holding the router in any other position, vertically, horizontally, upside down, cause the router to vibrate at those specified RPM’s?

1 Like
5

Hi Ed,

yes the rpm part is stable, and smooth.
Regarding the position, as soon as i take it of the shapeoko it stops doing weird noises.
I tried everything but upside down and no noises.
To me, the weird part is that when its mounted on the shapeoko, the lower the Z carriage is, the worst the noise is.
Regarding the router brushes, i have checked both and there’s still a lot of material left (according to the manual). I just hope that its the router (left it at the shop so the warranty guys take a look at it.), because if its the Shapeoko i have no idea where to look at…

Maybe i need to get my shapeoko a spindler conversion ( if that’s possible at all).

Thank you.

6

I suppose if you were fortunate enough to have a spare router to swap, you could decipher whether it follows the router or the machine.

1 Like
7

Hi Brian,

no, i had nothing I could swap it with.
I almost bought a new one just for test sake, but then reality hits and I don’t have money to waste.
Got to wait for the warranty…

8

that’s a bearing noise in that router…
bad or slipping bearing

9

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.