My dilemma of changing to a water cooled spindle just for noise abatement has ended. I have my SO3 in a cabinet and did some changes and checked on progress:
Background noise was 18 - 19 DB
Makita running with cabinet doors open about 75 DB
Makita running with doors closed about 70 DB
Then I took fiber board or Homasote or whatever you call it and added it to the sides and back of the cabinet. With the doors open, it reduced one whole DB ( margin of error). With the doors closed it is now 67 DB. So I gained 3 DB.
I do have a gap between the doors and at the bottom of the doors, so I think fixing that would help.
The real savings were when I put my Bose Quiet Comfort 35 headphones on. Already had them so it was basically no cost.
So, do you think the enclosure was enough of a benefit to make it worth the cost/effort/inconvenience? I also use Bose headphones and thought about adding an enclosure, but those numbers seem lower that what I would have guessed it would do. But, I’m not used to talking in DB, so maybe this is more of a difference than the numbers appear to show?
Have you decoupled the Shapeoko from the cabinet? If not I recommend watching this video:
It is about 3D printers but the same concept also applies to CNCs. If you have not decoupled it, then your Shapeoko is vibrating the cabinet which then acts to amplify certain frequencies of noise.
My Shapeoko is sitting on a 3/4 piece of MDF that is sitting on two layers of EVA foam floor mats that I got from Harbor Freight for like 12 dollars. The MDF adds a bit of weight to the vibrating mass of the Shapeoko. The mass helps to reduce the amplitude of the vibrations. The EVA foam helps to prevent those vibrations from reaching the cabinet. This coupled with making the cabinet air tight went a long way towards quieting the beast.
I do think the cabinet is worthwhile. The most objectionable noise was the screaming of the router. The cabinet seemed to reduce the more annoying sounds. With the doors shut it is almost an acceptable level of sound.
I have not decoupled the SO3 from the cabinet, I will experiment more with that. The measurements I took were of only the router noise and the steppers were not even powered up. I think just taking the router out of the clamp and lay it on a piece of foam so not noise transmission. Hope to try that this weekend.
I also found the router’s dentist drill noise impossible.
Remember that cutting creates a whole new set of noises, most of them at lower and broader frequency range, thus harder to deal with than just the free spinning router.
If you’re going to try isolating, consider making up a thin torsion box and bolting the Shapeoko down to it so you have a rigid structure for the Shapeoko first. Rigid structures tend to vibrate less (subject to tuning) and therefore store less energy and transmit less noise. It also helps if you can trust your spoilboard is actually level, will stay level, and doesn’t flap about when cutting.
I just went downstairs and performed an experiment. The background noise was still in the 18-19 DB range and the router while mounted in the SO3 was still at 74 DB. I took the router out of the SO3 and held it in my hand, I expected the noise level to go down. It remained at 74 DB. It looks like the screeching of the router is not being transmitted much through the physical connected and that decoupling it from the cabinet will not help that noise. I’m sure it would help with the cutting and stepper motor noise, but they don’t seem as objectionable.
I thought about making the cabinet air tight but that would pose a cooling issue.
Whilst I still used my AMB Kress spindle I wore my Westone in ears with the Comply noise isolator tips under my Peltor ear defenders, I still could only take a couple of hours of it…
That’s pretty low db, unless your room is soundproof.
The average human whisper is around 30 db at 3 feet distance.
per each 6 decibels added, the sound pressure is doubled. (or is it 3… i dont remember)
The a-weighted/fast measure in my living room with only the fan on this laptop running I measure 37db.
You might check your db meter.
I’m just using a sound meter on my phone. Figure it is good enough for relative measurements. I do not have a reference. My ancient memory tells me that 3 DB is the smallest difference humans can hear. The measurements were taken in my basement shop with nothing else running and no one else at home. It was pretty quiet.
I have thought about doing baffles on air in and air out into an otherwise sealed cabinet. Would have a low noise muffin fan moving air. That is probably more of a long term project at this point.
