Hi and Hello
Reading this thread raised an Idea and I have tried a very simple design made with NinjaFlex.
Attached is the STL file for a very simple but effective damper for the Mini Y Axes.
Most probably not as good as the professional dampers.
Never the less my wife loves the result 
The small Flex-Washers work best between the frame and the original washer.
All the Best
Frank
NEMA17_damper_2.stl (125 KB)
Had the same issue. What worked for me is heating up the pulley with a chefâs torch (used for cooking) and then gently tapping with a rubber mallet until it slides down a bit. Then I used a screwdriver to pull it back up again as far as possible. Had to repeat these steps a few times before it came off eventually. Used a bit of sandpaper to widen the hole in the pulley. Now it slides on and off like a glove 
I also had to buy a 1.27mm (0.50") allen key to remove the set screws. The 1.3mm I had laying around didnât work for me.
But wow, what a difference! This is the best mod you can do for your printer!
Iâm currently in the âcanât get the set screws looseâ camp as well. One of my (admittedly junky) allen keys actually started twisting around its axis (spiral hex keys⌠yay) and the screw didnât even budge!
Going to just order a replacement motor+pulley and then work on extraction after I drop in the new one. That way I have as much uptime as possible and will have a spare motor just in case.
Update: got my replacement motor+pulley today and installed it. HO. LEE. CRAP. So much quieter now!
Now to work at cutting the pulley off of the first motor so that can hang out in reserve should I need it.
Iâm also having a heck of a time getting the pulley to move after loosening the set screws.
Heat it up or use a gear puller? Opinions?
I donât know if itâs the best way, but I just inserted a large flathead screwdriver in the space all the way to the pole and twisted to pry it up. It didnât take too much force, but those things are on there pretty dang tight!
How can such a small thing reduce that much noise?
The stepper motors make noise for the same reason you can hear a music box when it is installed, but barely aware that it is running when removed from the jewelry box, figurine, or whatever it was in. It is easy to test this. Remove the screws and remove the music box, wind it up some and listen. Then put it on your kitchen table or other large preferably hollow wooden surface and listen. Night and day. The vibrations of the music box are transferred by direct contact between its frame and what ever it is mounted to which serves to amplify the vibrations through resonance.
Another example is the difference between an electric guitar that is not plugged in or powered versus an acoustic guitar. The electric guitar resonates some but you can still just barely hear it because it doesnât have all the hollow space inside nor the surface area that the acoustic does to allow for the amplification of the sound. The vibrations of the strings are transferred through direct contact with the body of the guitars.
The dampeners work by absorbing the vibrations of the stepper motors before they can be transferred to the sheet metal frame of the printer which has a large surface area and is essentially hollow (just like the acoustic guitar). You will still hear some small amount of noise due to the vibrations being transferred through the motor shaftâs mechanical connection to the other parts of the printer and the screws that mount the motor to the frame.
Just added the damper to mine - huuuuuuge difference. This mod should be a requirement.
I also noticed the new Mini (next release) will have one of these installed at the factory.
Somewhere I saw some half height motors that I was curious if could be used to replace the Z-axis motors allowing clearance for dampers to be installed.
Half height motors do not have very much torque or hold power, so using them for such a heavy motor load as the Z axis would give a poor chance to work.
Makes sense. Donât know enough about the components involved to realize the. Learn something every day. Thanks!
I recently added a set of Astrosyn dampers to my X&Y AxesâŚThen I removed them.
Though the noise was slightly less, I could see no improvement in print quality (ringing and other harmonics), and the tilt that was introduced to the steppers when tightening the belts down seems like a recipe for problems down the road, including Increased belt wear, unusual loads on the stepper shaft/bearings that may cause damage to the steppersâŚ
My solution to noise is three-fold and results in a nearly silent machine (My girlfriend can no longer hear it in the room directly below the printer at all. She requires complere silence to work):
-A Plexi enclosure (helps some)
https://www.liteworldllc.com/store/liteworld-protective-enclosure/
-Sorbothane discs under the four feet of the table the printer sits on (helps a lot with noise going through the floor)
https://www.amazon.com/gp/product/B0042U8P9C/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
-And the biggest and best difference? âStinger Roadkillâ (really great.)
https://www.amazon.com/gp/product/B001TH8OC4/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
The stinger is essentially mass loaded vinyl with a layer of foam. The foam absorbs vibrations, and the vinyl reflects any vibrations that make it past the foam. Use it soft-side up. Really nice.
The closest tool I had lying around was a T5 (torx), which fit snugly and did the job perfectly without damaging the driver and hopefully the screws. It felt very tight without room for damage.
The result is really amazing btw!
I just wanted to say how much this thread helped me stay in the house! The wife was ready to kick me and the printer to the curb but with just the damper on the Y axis it is an unreal difference! She was more shocked than me at how much this one little part helped. I have printed several calibration parts and see no difference in print quality. The sound difference is unreal!!!
Steve
Thanks to everyone that posted. WHAT A DIFFERENCE!
I made a little guide http://www.processio.com/lulzbot-mini-y-axis-noise-killer/.
Hope it helps.
My only real question is âWhy didnât this come standard?â I love this upgrade! I can actually stay in the room with the printer now. It is an amazing difference.
The Y-axis dampener is actually a part of the Mini 1.04:
https://ohai.lulzbot.com/project/mini-104-y-axis-assembly/mini-v104/
I registered just to say this mod is awesome. Thanks so much
Indeed, even a plug vibration damper has a major effect. The Astrosyn vibration damper is a stunning bit of tech.
These dampers are ASTOUNDING!
I was fortunate enough to have been given a broken Taz6 about a month ago- it had been in an architectâs storage room for a few years. While cleaning it up I found that the retaining piece that holds the y-axis belt to the front of the frame had a small crack which was probably the original problem- it was hard to see but enough to throw off prints since it opened only when the travel was in one direction. After making a new part, upgrading the firmware, calibrating, etc. the printer worked beautifully, but I made the mistake of allowing a 19-hour print to go overnight (the printer was in a bedroom directly below the master BR), and my wife nearly killed me in the morning because the noise kept waking her up.
I got two of these dampers and put them on the Y and X axes, put some felt furniture feet on the table contact points, and now the loudest thing about the printer is the fan. Freaking amazing difference!
Any manufacturer that sells a printer without dampers like these (as at least an optional extra) is FOOLISH!
With the exception of trouble getting the pulley set-screws loosened to move the pulleys to allow for the thickness of the dampers, this was a 20-minute process.
Happy wife, happy life!