For me a simple rheostat speed control helped a lot with the noise. The shop vac is still pretty loud though
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If that’s the case I think I’d rather build an enclosure for the vac than for the MPCNC. Things I need to decide on soon as my parts bundle is ‘out for delivery today’ and FedEx is due with a spool of filament and I can finish printing parts.
You can’t cancel noise at the source like in headphones that cancel noise at your ears, it just isn’t possible. Weight would not be an issue as you just need about 6 layers of cotton towels sandwiched between 3mm of ply.
I thought I’d read something in the past of noise being cancelled in either an aircraft cabin or auto through a speaker system. It may have been something Lotus Engineering was working on.
In enclosure walls or?
Nope, not possible; there was a scam product on kickstarter that claimed to be able to do it and guess what everybody was very disappointed. You can only cancel noise at one point in space by generating the negative sound wave at that point.
Not the enclosure, a redesigned dust shoe maybe not ply but 3D printed in two parts
I don’t remember all the facts but I’m talking about something I read a good 35-40 years before kickstarter was even an idea. Perhaps it never panned out but the plan was to measure ambient sound in the interior and generate an exact opposite signal. If not Lotus it was likely some other legitimate automotive company as that was of big interest to me at the time.
It has always been the killer tech to be able to pull off, sound cancelling headphones being the exception because of the controlled space (your ear canal). To pull it off you would have to generate a negative wave at every point in space, as sound travels at a relatively slow speed you would have to have an infinite number of speakers at every point the sound can travel to. Aircraft just have very good sound insulation built into the structure but sit at the back and noise levels go up by quite a bit.
So back to towels we go.
You would need the negative to be sourced at the same location as the noise. If it is off to one side, there will be areas where it is doubled and not cancelled out.
I use hearing protection. The vac is probably the loudest part in my set up.
A number of people have shared that thought. I think a vac enclosure may go on the list ahead of an MPCNC enclosure. I wore foam ear plugs for years while motorcycle riding and wouldn’t mind them while using a machine but I’d like to quiet things as much as possible to keep on good terms with the neighbors.
What bits are you using Jeff? My 6mm 2 flute straight cuts scream yet the 9mm is a lot better, the 3mm single flute is okay but not as bad as the 6mm. I use the larger bits for speed.
My router screams, but I’m using a dewalt again. The cheap chinese spindles are just that, cheap.
There is a huge rpm difference there… I assume dewalt has about 30.000rpm and my Chinese 500W has 15.000.
The bit itself has an recommended max rpm but when I was in school I learned machining and such and you are very careful calculating RPM for your work be it milling or using a lathe.
I have no doubt same can be applied here even if we do work in softer materials.
RIght, but there’s still the trade off of the chinese spindles having a metric ass ton of stick out. I can take bigger(deeper) cuts with the dewalt than the CN spindle because of this.
In principle I like the idea of enclosing just the router, instead of the whole machine.
However, if you enclose the whole router, heat is going to be an issue. Enclosing just the end mill may help with the screaming sound of cutting, but my router itself is uncomfortably loud, even at lower RPMs (like 20k), even when it’s not cutting anything.
Also, any air gaps are going to leak a lot of noise. If you only make slotting through cuts or carvings in flat stock it may work out, but a pocket will let out a lot of noise for example.
As for the noise of the vacuum, I think there is an easy solution. If you use a good cyclone, then I think you can use a normal vacuum cleaner. Those can be far quieter than shop vacs.
Noise cancelling in an enclosed area is possible, but you have to be in a controlled environment. My truck has noise cancelling. There’s microphones in the headliner of the truck that picks up the sounds near your head. It then cancels out the engine and road noise and plays it out the speakers. I haven’t tested in any scientific fashion to prove it, but I think they partially disable it when you floor the gas pedal because the engine suddenly gets much louder.
Out of all the options mentioned in this post, enclosing the entire MPCNC is probably the easiest thing to do. Enclosing the shop vac would help with the other half of the noise producing items.
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I have only used 1/8" (3.175mm) bits.
I wonder – would it be harmful to put the vacuum on a speed control? It shouldn’t need max power to remove some chips/sawdust.
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As long as it runs fast enough to cool the motor it should be alright.
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Had one overheat once but the plastic tarp was to blame I’ve never run my shop vac long on the speed control but it did reduce the noise. The noise was secondary to not wanting golden retriever hair in a cloud turned it down and rolled it to the door worked fairly well I hate the spring and blown coats