Sound Isolation Box Makes Living Room Based CNC Routing Tolerable

CNC Machines can be loud, especially if they are equipped with a high-speed router spindle. Unfortunately, such a loud racket could be a problem for the apartment dwellers out there. Fear Not! [Petteri] has come up with a solution. It’s a sound isolation enclosure for his mini CNC Router that doubles as furniture. It keeps the sound and dust in while pumping out some cool parts….. in his living room.

What may just look like a box with an upholstered top actually had a lot of thought put into the design. The front MDF panel folds down to lay flat on the floor so that the user can kneel on it to access the machine without putting unnecessary stress on the door hinges. The top also is hinged to allow some top-down access or permit a quick peek on the status of a job. All of the internal corners of the box were caulked to be air tight, even a little air passageway would allow sound and dust to escape. Two-centimeter thick sound insulation lines the entire interior of the box and the two access lids have rubber sealing strips to ensure an air tight seal when closed.

With stepper motors, the spindle motor and control electronics all running inside an enclosed box, there is some concern over heat build up. [Petteri] hasn’t had any problems with that so far but he still installed an over-temp power cutoff made from a GFCI outlet and a thermostat temperature switch. This unit will cut the mains power if the temperature gets over 50º C by intentionally tripping the GFCI outlet. None of the internal parts will ignite under 300º C, so there is quite a safety buffer.

Although the isolation box came out pretty good, [Petteri] admits there is room for improvement; when cutting wood or aluminum, the noise level is kind of annoying. If he had to do it again, he would use thicker MDF, 20mm instead of 5mm. However, during general use while cutting plastic, the router is still quieter than his dishwasher.

Video below.

22 thoughts on “Sound Isolation Box Makes Living Room Based CNC Routing Tolerable

    1. Heat is a big issue… If I don’t leave the door and window open in my work area my steppers will spike to 165F! If you lower the current down enough they’ll be fine but then you could have such low torque that stalls will become an expected occurrence.

    2. “With stepper motors, the spindle motor and control electronics all running inside an enclosed box, there is some concern over heat build up. [Petteri] hasn’t had any problems with that so far but he still installed an over-temp power cutoff made from a GFCI outlet and a thermostat temperature switch. This unit will cut the mains power if the temperature gets over 50º C by intentionally tripping the GFCI outlet. None of the internal parts will ignite under 300º C, so there is quite a safety buffer.”

        1. Well it didn’t have trouble with 2 hours of continuous milling at practically the maximum load for the CNC3020. The steppers were around 50-60°C (hot to touch but not burning skin). I measured the air at around 40°C. I usually peek in every 15 mins or so to vacuum out some dust, so that lets out heat quite effectively.

  1. What kind of feet does the box have? I wonder if isolation mounts or spongy rubber feet would lessen the sound further by preventing the floor from acting like a sounding board. Then again – raising the box up would require different hinges for the front panel or feet on that box to even the heights up, breaking the clean aesthetic the box has when closed right now.

  2. Want it deader, just cover it in more carpet foam and build another box around it all.
    Layers if foam and mass alternating is the best way to kill noise. Just like a multi-section filter.

      1. Yep. Long time ago my school built an anechoic chamber for the Audio Video team (or maybe it was the Music Department, can’t recall anymore) by covering the walls with egg cartons. Students were asked to bring the cartons in.

  3. I would be concerned about the motor temperatures too, spindle and stepper. While the ambient temperature may be monitored to not go above 50 C, the spot temperatures on the motors could exceed that significantly especially when you consider that the steppers on the Chinese CNC units are mounted with plastic (albiet decent) couplers. These don’t transfer heat worth a damn to the router frame.

    In an area in my basement where I run my unit, it’s open all the time, and there are times that those motors get mighty hot to the touch. I’m considering heatsink installation on those to improve dissipation.

  4. Mount the electronics outside, cool the stepper with small fans. Get a water cooled spindle (runs much quieter) and also helps to remove heat from the enclosure.

    I also have my CNC in the living room and I’m also thinking about an enclosure for it.
    But as long my neighbors are using these noisy vacuum cleaner…

  5. I would think that sound dampening would improve the SAF of his router. Plus, not all of us enjoy the constant loud noise from running cnc equipment. I get annoyed with my 3D printer’s noise sometimes and its not even close to a cnc router noise wise. Also, there is a safety factor in reducing ambient noise. Long term exposure sound pressure limits are lower than short term limits, and hearing loss is not fun.

  6. A safer solution for the temperature cut off switch might be to ground the load side neutral to ground rather than a load side hot to line side neutral connection However if the gfci failed then it wouldn’t create a dead short and hopefully trip the circuit breaker/fuse to save overheating the cabinet.

  7. I would be worried about the possibility of a fire or explosion due to containing wood dust inside a sealed enclosure along with several possible ignition sources. Depends on what kind of chips you’re generating – fine dust or larger chips. There’s a Wikipedia article on the topic.

    1. Well if the dust does catch fire, I’d much rather it be inside the box. The lid is free to open, so no danger of pressure build-up, and the fire should die down quite fast due to lack of oxygen.

      But mostly the aim is to remove material as chips rather than dust.

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