CNC Enclosure - Soundproof and Dustproof

I wanted to buy a CNC Router for quite some time, but unfortunately I never was able to afford one, nor I had the space to put it. At least the first problem wasn't holding me back anymore, but living in a one room apartment without a workshop still was a concern. After doing some research, I realized that I should be able to enclose it in a way, that all the noise and dust should stay within the enclosure. With the first covid lockdown being around the corner at that time, I decided this would be a good time to start the project of buying and enclosing a CNC.

The most important points obviously were to keep all the dust within the enclosure and make sure it is quiet enough to run it in an apartment. I also wanted to keep it as small as possible and try to blend it into the room, so it still remains liveable and won't look like I am living in a workshop.

After a few iterations, this is the design I came up with.

A frame made of squared timber, with 18mm MDF covering everything to create a really rigid frame. Between the timber there is enough space to add some 20mm thick foam, to help absorbing some of the sound. In the front door, there is a cutout for a window. The window is made of two 8mm thick polycarbonate sheets with air in between them, which allows me to look inside, while still keeping most of the noise inside.

Next to the CNC I left some space to eventually add a small dust extraction system.

With the design being finalized, I went and bought all the materials - just days before all the hardware stores shut down during the first lockdown.

Living in a one room apartment also means that I had to build the enclosure inside. Luckily I bought the MDF already cut to the right size, so there wasn't that much woodworking left, besides cutting the timber and cutting some holes in the MDF. Everything is both glued and screwed together, for maximum rigidity.

With the frame being finished, I added some light gray felt to the outside. This helps blend the enclosure into the apartment without looking like a huge wooden box. Besides its height, you could think it is just a storage box which also doubles as a bench to sit on it. The felt might even help a little bit with sound dampening as well.

On the bottom I added 9 small rubber feat, However I later on added some of the high density foam under the enclosure to decouple it from the floor and therefor prevent resonances from travelling into the ground. Which was way more effective than these tiny rubber feet.

Now for the sound isolation, I added the 20mm thick, really heavy, dense foam. This was the highest density foam I could find which should help with sound isolation. Besides the foam, I also added some alubutyl, which I still had leftover from upgrading the audio system in my car. If it is really necessary? I don't know, but I don't think it will do any harm.

To see what is going on inside, I added some really bright, high CRI LED strips on the inside, both on the front and on the back, angled towards the CNC.

To keep the noise contained within the enclosure it is really important to keep the enclosure sealed and have as few openings as possible.

For the front door I used some closed cell foam combined with latches that pull the door closed. The window is made of two 8mm thick layers of polycarbonate with an air gap in between and also some closed cell foam to make it as airtight as possible.

Overall I am really impressed with the result. At that time I placed a speaker inside the enclosure, put in on high volume and after closing the door you could barely hear it.

With all the foam being exposed and making cleaning difficult, I decided to add another thin 3mm piece of white coated MDF to the walls. This brightens up everything inside and also makes cleaning a lot easier. To prevent vibrations to travel directly from the CNC to the frame, I cut these MDF pieces smaller than the foam pieces and just glued them onto the foam, which decouples the CNC from the frame. The gaps between the MDF and the frame where just filled with some acrylic.

For dust extraction I added a tiny vacuum cleaner inside the enclosure. The place was very tight, and it only fits with some minor modifications to the casing of the vacuum and if it is positioned at a slight angle. Therefor I added a 3D printed piece on the floor which helps to align the vacuum cleaner properly.

Having the vacuum inside the enclosure is not an ideal solution, but it seemed like the best solution for this setup. If I would have placed it outside, there would be a lot of noise by the vacuum cleaner and it could not work properly, since the enclosure is mostly airtight, it would just try to pull a vacuum on the inside. But having it inside, also means that it heats up the air inside quickly. So it can not run for a prolonged time, I only turn it on occasionally. Being so small the bin also fills up quickly. Still, for cutting MDF etc. it is really nice to have some sort of dust extraction.

At first I was also concerned with having an electric motor inside a closed chamber with all the dust in the air, but after watching it and seeing the little amount of dust that's actually in the air, I don't think this will be a problem.

The dust extraction has its own 230V outlet which is controlled by the CNC controller.

Overall the enclosure works much better than I originally expected. While you can still hear the machine and hear when something isn't sounding right, it is really quiet and you can just sit next to it.

The door slightly limits the travel on the y-axis, but this is a compromise I was willing to make, to keep the enclosure as small as possible. If I ever need the full depth, I can still open the door and use the entire work area.

The gray felt on the outside and the white MDF on the inside give it a clean aesthetic, while still being functional and easy to clean.

With the depth of the enclosure, I am giving up on some travel on the Y-Axis, since the spindle will hit the window if it is at the very front. But this was a sacrifice to keep the enclosure as compact as possible. If I really need the additional Y-travel, I can still open the door a bit to regain it.

I am really happy with the outcome and it is great to be able to even tackle some more complex projects, even without having a proper workshop.