Creality K1/Max Fan Muffler (WIP)

Since Input Shaping came out and printers became faster and faster so too has the noise increased from their part cooling systems.

The Ender 3 had one little 4010 fan on it, most printers now have two powerful fans. The Creality K1 and Max have a huge side fan that spits out 67 or 68dB. The FLSUN S1 and similar high speed printers often have CPAP fans pushing over 80dB.

As printers get faster so too will the noise from their fans so expect printers to get louder and louder. Something needs to change.

We tried some fan mufflers you can find online but with minimal success. Most only gave minimal effect and limited fan performance so we experimented with other designs. 

We found that for airflow to be preserved the chamber needs to be large and also found that resonance chambers were the best in muffling sound rather than fins, baffles or perforations. So we tried a few designs and here are the results so far. This page will remain open as we try other designs and what has been uploaded so far is purely experimental. They are not exactly meant as upgrades but we wanted to share what we learned and we invite you to mod these to your hearts content.

The best results came from long chambers. We tested the peak frequency of the K1 fan in order to find out what wavelength of sound needed to be muffled. The chambers conform to a length that allows the sound to reflect back completely out of phase which interferes with more incoming sound and reduces its intensity. So far we have been able to reduce the noise from that fan from 67 or 68 dB down to 64 or 65dB which doesn't sound like much but remember the decibel scale is logarithmic rather than linear.

The “large chamber” reduces noise to that amount however the output airspeed is reduced to 5.1m/s from 7.5 m/s. 

The “even larger chamber” reduces the same amount of noise however the airspeed is only reduced to 6 m/s.

While researching this we came across an article about a team from Boston University who 3d printed a sound muffler. You can find the article here: https://www.bu.edu/articles/2019/making-the-world-a-lot-quieter/

It is essentially just a ring with a helical pattern on its periphery (its actually just a 5-start thread embedded into a ring's outer walls). So we designed it. It doesn't give much of a sound reduction, 1-2 dB but the airflow is unaffected completely. So it shows some promise.

In the coming days, we will update this page with another design and continue after that.

The large chamber should be printed in the orientation shown in the photo. The even larger chamber should be printed lying down and the Boston university design should be printed as in the photo too, watch out so you don't get support stuck in the helical shape!

All printed at 0.2mm layer height on a K1 Max.