So here’s the problem:
I’m sharing a single-room apartment with my MPCNC - so sound and dust are a mayor concern for me. So I have to build an enclosure. Until now I have come up with three different options regarding the soundproofing but I am unsure which to chose.
Regardless of the option the enclosure will have a double-glassed window out of some sort of so sort of translucent plastic.
Option 1:
Building the Box out of 18mm MDF
Option 2:
Sandwiching acoustic dampening material (like rock wool) with 3mm MDF on both sides
Option 3:
Same as Option 2, but with an additional layer of a bitumen-plate (as used for rooftops)
From what I’ve gathered, soundproofing of high frequencies is mainly achieved by high mass.
Any ideas/suggestions?
I made an enclosure for my 3D printer of 18mm MDF. The main purpose was to have a heated chamber for printing ABS. I have a Prusa i3 MK3S which is really silent. But in the enclosure it actually makes more noise. I put eggshell foam on the insides, didn’t really make a difference. The enclosure works like a guitar in a sense: the box amplifies the sound. It does not dampen the noise at all.
For my MPCNC, I made a soundproofing enclosure with 45mm rockwool sandwiched between 8mm MDF. It works very well! I tried to measure the decibel difference with my phone, but it’s very unreliable. Without the enclosure, I think it’s too loud to stay near the machine for more than a few minutes. Inside the enclosure, it’s fine.
Some pointers though:
A vacuum is also pretty loud. I built the enclosure, found out I wanted a vacuum, and then built an enclosure for the vacuum… lots of work.
If you get a router that has speed control, you can maybe run it at lower speed. That will help a lot with the noise level.
An enclosure for a decent size MPCNC (mine is 100cm x 75cm) gets pretty big and heavy! I put it on wheels, and keep it under my workbench. I don’t think I would want it taking up all that space in a single room apartment.
I also planned to have a window, but in the end I did not do that. You really do not want big holes in your enclosure. If I lift the lid just a bit, that already lets out a lot of the noise. I’m afraid that window will also leak so much noise that the enclosure just doesn’t work well. I haven’t tried it though. Instead, I put a Raspberry PI with a camera inside. When I start a job, I just lift the lid to see if all goes well at first, and then monitor it on the camera from there. I also put a light bulb inside of course.
Regarding dust btw, I got a vacuum with an optional filter bag. But even so, there is a very fine layer of dust everywhere in my garage now after cutting some MDF on my MPCNC. If you don’t want dust everywhere, you probably do not want to use a vacuum, but you’d want to try to keep all the dust inside the enclosure. Or vent outside of course.
You can do a window with 2 thin layers of plexi and an air gap inbetween and it’ll work a lot better than a single pane. Not as well as the rest of the box though.
As for the spindle, I’ve got a 800 W, water cooled, vfd controlled spindle - so at least that part will be quiet.
Dust collection wise my plan was to seal the enclosure so I will only have to vacuum once the program is done. I’m thinking about using a aquarium air pump to blow away chips - should be much more quiet than a vacuum.
So the only sound I have to dampen, is the endmill cutting the material.
Regarding the window however, I definitely want one. I was planning on using the method @EdNiedziejko mentioned, two thin layers, air-gapped. I will keep them small, but I definitely want a window.
As for the space: Yeah. Sometimes you just have to compromise. And unfortunately I don’t have access to a garage/shed/basement anywhere near me - So, MPCNC in the living room it is
I am interested in trying a few things with the shop vac… Running the output air into a lined box for one, since that seems to be where the majority of the noise is coming from. I haven’t seen anyone do it yet but maybe having the vacuum exhaust blow in one side of the enclosure while the intake sucks from the other side would work. It might eliminate the need for a dust boot.
I saw something like that on a bobs cnc. Instead of the vac exhaust it was fresh air, but the whole enclosure was caulked and sealed, so the inlet tube (on a hosr and everything) sucked in a bunch of air directed right at the mill to blow chips away. The exhaust coming out of the shop bag can get pretty warm, though. The water cooling on the spindle might need to be pretty good, other tools like the dewalt might not like it, and I think the shop vac would definitely get angry.
This is what happens to a plastic bucket with chips spinning around in it for 20ish hours straight. It was in the mid 60sF that day. The plumbing path for that was air sucked in through the dust shoe on the dewalt, to the cyclone, to the vac behind the bucket. The chips take the heat away from whatever you were cutting, the heat has to go somewhere, most just radiates into the airstream, but the dust collected is still warm. If you enclose a vac, it has to have some kind of cooling air for the motor, they get stupid hot real fast in a small insulated box.
The biggest problem with the vacuums air inlet in my opinion is, that restricting the airflow in any way will put more load on the motor.
I’ve been thinking about the video @mordiev posted. But instead of going with towels, I thought about maybe lining the inside of my enclosure with cheap carpet - then I would have a combination of soft material to absorb the sound and the heavy enclosure (still thinking about sandwiching in a layer of bitumen) to dampen vibrations. I’m hoping that will be enough to bring down the level of the cutter to a acceptable level inside an apartment
