My Glowforge makes a very loud noise when starting printing. I will do a video for you.
I already cleaned the fan. What else could it be?
We will need the video to understand how to answer that… 
Is this a new noise, did it just start, does it always do it, only when it starts up and not when cutting… etc…
Mine sounds like a small jet starting up when starting a cut / etch. Time to clean the fan! 
The sound level varies because Glowforge changes fan speed based on the operation being performed. It can vary from a low rumble to a loud vacuum if you’re doing a ton of stinky material continuously.
Go ahead and post a video and we can take a listen.
It’s been a little while since I’ve seen any replies on this thread so I’m going to close it. If you still need help with this please either start a new thread or email support@glowforge.com.