I have recently purchased a 3D printer, mostly because I was interested in learning about 3D printing, and of course, because I wanted one. Between buying a ready to print one and sourcing all parts individually, I went for a complete kit. I though getting a kit that needs assembly would allow me to learn more about it and I would enjoy assembling it. So, I went for a prusa i3 steel, because i wanted something capable of both ABS and PLA from the start and should have reasonable endurance.
Clearly, the thing is noisy, without any tuning it was constantly over 70dB, peaking at 75dB for some motions. Since I keep it next to my computer desk where I spent most of the time, I am troubled by it. So i made some changes to try and reduce the audible noise. For noise measurements I have used my smartphone with Audio Tool app and an IMM-6 calibrated microphone placed about 1m from the printer.
1. Support. Place the printer on something as rigid and heavy as possible. I found that tables are not that great, but a drawer set works better.
2. Decouple from the support, in order to minimize vibration transmission. Apart from a layer of foam, I used 4 furniture support feet placed under the Y carriage, which means that now the 3d printer touches the ground in less and smaller points than before. This helped a lot.
3. Play with printing speed. As a mechanical system, the whole printer is prone to have certain resonant frequencies and it turned out that the default 50mm/s speed was the loudest possible.
4. Change the motor drivers. The biggest change I have managed to make in terms of noise was to swap the original A4988 X and Y drivers with DRV8825. While these produce a high pitch wine, the mechanical noise is strongly reduced, i managed to get about 8-10dB.
5. Fix the power supply fan. The most annoying thing about it is that it cycles ON/OFF, not continuously variable according to the temperature. Of course this is acceptable for an industrial power supply, but not for home use. I could have replaced the control with a variable speed one, but there is not much to gain here either: the fan is small and placed in a closed space. The solution i settled for was to replace it with a 9cm fan, the largest I found in my parts collection. After cutting out the previous guard, I mounted the fan as far away from the case as my screws allowed and sealed the area around with duck tape. This is to allow the air to flow easier and keep the fan blades away from the big aluminum plate which would cause noise. Of course, no fan is complete without a red guard on top, with a bit of scaling. I left the original control in place, but I added a 50 ohm resistor as well, to keep the fan turning at lower speed. My goal is for the original thermostat that puts the fan at full power to never trigger. Some tests have shown that this performs as desired, even the outside of the power supply stays cooler then before. This is clearly beneficial and should increase the life span of what is not such a great quality power supply. Check below for the build pictures below.
What is inside the typical not so high quality, 360W, 12V LED power supply:
For thermal regulation, the power supply uses a simple mechanical thermostat placed inside the filter inductor, which switches the fan on at 45°C and switches it off at 33°C. Since the printer does not draw much power, the fan cycles ON and OFF, which is not that great for all the components, since they keep cycling between the 2 temperatures.
I have removed the original fan and cu the grill to improve airflow as much as possible. The fan is placed at about 1cm further away from the case to reduce noise.
Tape is used to seal the gap
I connected an extra wire to the positive supply of the fan to be brought outside in order to add a resistor to keep the fan at idle speed.
Ending with some experiments for idle speed
Of course, no fan installation is complete without a red grill
Note: The E3D fan is small and it’s quite noisy, if the printer does not print. Otherwise there is no difference in noise with or without it, so there is no need to replace this one with something larger.