Reducing noise and dustJune 24, 2018 Maker
As my 3020 CNC is inside in my home, I prefer it to run as quietly and as clean as possible. That’s why I’ve built an enclosure large enough to fit in both the CNC and a small vacuum cleaner.
The enclosure is made out of 18 mm MDF panels because they’re relatively cheap. After the build, I did read that MDF isn’t the best choice of materials for soundproofing, but I still do not know how big a difference it actually makes. I padded the interior using 20 mm thick soundproofing mats, and used a single large 10 mm polycarbonate panel as a door. There are also soundproofing mats underneath and behind the enclosure.
The enclosure does a decent job of limiting noise from both the CNC and the vac, probably reducing it by 15 dB or so. It is, however, better at filtering out airborne high-frequency noise than low-frequency vibrations passed on directly to the enclosure. So listening from outside the room the enclosure is in, you can still hear a slight low-pitched hum when actively milling.
The vibrations can probably be further reduced by increasing the thickness and density of the foam mats on the bottom. Still, the current setup is already so useful that I haven’t felt the need to invest in this. Also, the large 10 mm polycarbonate door seems to resonate a bit, so that will probably be another limiting factor in noise reduction anyway.
To easily get the necessary cables in and out of the enclosure without having to worry about sound or dust, I drilled a single 44 mm hole in the back, ran the wires and connectors through, and stuffed it back up again with a piece of cloth. Simple and effective. For lighting, I mounted two parallel LED strips running over the full width of the enclosure’s ceiling. That way, the tip of the end mill and the work is never in shadow. Lastly, I added a simple webcam to the side of the enclosure, allowing me to keep an eye on things when I’m not in the room.
To keep things clean, I’m using a small ash vacuum cleaner. To get the vac’s nozzle close to the mill’s tip, I’m using a relatively thin plastic tube as a hose that I tie-ripped to the spindle. To connect the hose to the vacuum cleaner, I simply made an adapter out of MDF, and used a nail in each side so that it would connect to the threading on the vac’s side. The hose gets the job done, but its small diameter does noticeably reduce the vac’s suction power.
Having the vacuum cleaner inside the CNC enclosure as well helps with reducing the overall noise and minimizes the length of the hose, but can also cause heat to build up. Because the vacuum cleaner originally could only run at 600W, this quickly became a problem. So I hacked the vacuum cleaner and mounted a cheap Chinese 5000W SCR-based dimmer on top that I bought on AliExpress. Now that that’s installed, I can run the vac at 250W or so, giving me enough power to suck up most of the sawdust while preventing the enclosure to get hot (although it still does warm up inside a bit).
To turn the vacuum cleaner on and off, I added a 5V relay and a socket to my control box, and hooked it up to the flood signal on the CNC USB Controller board. That way, the vac is conventiently controlled through the CNC software.
Overall, I’m fairly content with the whole enclosure and vac solution. It’s silent, tidy and clean enough for my purposes, and large enough to keep the temperature from rising too much. If, however, I ever want an even more silent solution, I would probably start by adding more foam and make a padded wooden front door containing a noticeably smaller polycarbonate window.