Summary

I was searching for a replacement fan for my CR-10s and came across the big variety of models available on Chinese sites. There is little info available there so I collected datasheets from inet and made a summary here. I would definitely favor the quite models, as example HA model and KDE - PKS3 models in 40x40x20 and 40x40x10 configurations.

Be aware that rpm, flow capacity and noise are directly related to each other in a way that higher flow per minute require higher rpm and produce more noise. Also the flow is directly proportional to fan diameter, as bigger fans produce more flow at lower rpm and lower noise levels. The flow produced per rpm increase is not linear as the fan quickly looses efficiency, so two fold louder fans produce less than two fold air flow!

Be aware that noise is measured in dB, so 3dB difference is double the noise level, as example fan producing 21dB is twice as noisy as fan producing 18dB. Can take as a reference level the whispering at distance 1.5m which produce around 20dB.

I publish this info with the hope that it will be useful. I am not directly related to SUNON or any other brand. I am also not directly related to any Chinese shop or other shop in any way.

A very good fan cover for 40mm I found here (also included the file in my thing), be aware that printing time may be high (4pcs. printed from ABS = ~6h) and it need supports :

https://www.thingiverse.com/thing:3454477

Links:

https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20190925113203&origin=y&SearchText=HA40201V4&switch_new_app=y

https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20190925113302&origin=y&SearchText=HA40101V4&switch_new_app=y

http://www.sunon.com/uFiles/file/03_products/08-catalog%20download/Sunon%20DC%20Brushless%20Fan%20&%20Blower_(240-E).pdf

https://www.jameco.com/Jameco/Products/ProdDS/195899.pdf