Noisy Lulzbot Mini? I have the solution: add a damper!

I love my Lulzbot Mini. Truly, it is the best small build plate 3D printer out there. From the the day I plugged it in over a year ago and hundreds of hours of printing, I have never had a problem with it except a sheared axle on the X axis motor because of a bad batch of them that got into them when they first came out. That took 40 minutes to replace and was fairly annoying, so I will briefly cover that here, as well.

Below the tips on replacing the X Axis you will find the installation of a damper to reduce vibration and noise.

Replace the X Axis motor tips

1. I had to replace the X axis motor and couldn’t find the exact specs that Lulzbot has (and after several emails could not get an explanation as to why) so I bought it from them. Here’s a link to the NEMA 17 in the Lulzbot store. Note that it comes with the right wiring, as well.
2. Taking the 16 tooth GT2 timing belt pully took 20 minutes! As it turns out, Lulzbot uses some pretty aggressive locking glue which I had to burn out with a soldering iron in order to get my allen wrench into the grub screw.
   I highly recommend buying one or two of them and just replace it. Here’s the link to Lulzbot GT2 16 tooth pully gear  and here’s a link to some DROK GT2 pully on Amazon. I’ve bought a bunch of DROK stuff before and it has been great, so those should be fine. Make sure you have a 1.27mm or 0.05in hex key.  Also, make sure you have a good pair of needle nose pliers! You will need to grab onto the ends of the belt with them. Here are the instructions from Lulzbot.
   

Making the Y Axis wonderfully quieter with a damper

 

This brilliant damper above that fits all NEMA 17 motors consists of two metal plates that match the bolt holes of the motor. The two plates are attached by a heavy duty rubber. The difference it makes by reducing vibration is astonishing. Best thing I ever bought for the Mini.

You can buy a Moons Nema 17 Stepper Motor Damper from Lulzbot, or find them elsewhere on Ebay or Amazon, or Ultibots.

For this project you will need:

• Permanent marker
• Small ruler or some kind of flat edge
• 1x small zip tie to replace the one you cut
• 1x 1.27mm hex wrench
• 1x 2mm hex wrench
• Something to cut the zip tie
• Blue loctite (use it on all threads sparingly)

With luck, the 16 tooth pully came off a lot easier on the Y motor, but it will still a pain. I replaced it with a new one.

In Lulzbot’s instructions for replacing the Y motor it says to turn the machine upside down and undo the belt, but I decided to take the shortcut and just undo the motor. It came out fine and since mine is no longer under warranty, I figured it would be my problem if it didn’t work out.

First, unplug your Mini and turn it around to have the Y motor hanging off the edge of the table.

Push the build plate all the way back and lay your rule across the two slide rods. It looks like there’s about 1 or 2mm between the bottom of the ruler and the belt. Pull the build plate forward and check again. It should be able the same. You can measure this gap or eyeball it – this is where you want the height of the pulley to be when you are done (there’s more space than what it looks like in the pic).

Unplug the wire and snip the zip tie.

Undo the four mounting bolts a little at a time so not one bolt is holding all the tension of the pulley.

Take the two closest to the machine completely out, then the two nearest to you. Tilt the motor forward and pull the belt over the pulley (in the pic they’re just sitting in their holes not attached to the motor).

Use the permanent marker to mark the shaft – this is useful for aligment – then loosen the pulley screws so it can slide up the shaft, but not spin on the shaft – you want to keep the flat spot aligned with one of the scews. You will need to raise it in order to keep the belt aligned as you are lowering the motor with the damper.

Next, take a look at the damper itself. It has two threaded holes and two non-threaded holes. These are the same size as the Lulzbot bolts and you can use them instead of the ones that came with the damper. Don’t forget the washers, whichever ones you choose to use.

Attach the damper to the motor using the holes without threads. Align it as best as you can – the holes are oversized. It looks badly aligned in the pic because of the angle.

Place one screw + washer in the mount hole closest to you that will accept the threaded side of the damper. Prepare the other screw with the washer and stick the hex key into it so it will be easy to slip it into the remaining hole.

Tilt the motor forward and place it into the space for it and pull the drive belt over the pulley.

Loosely screw in the screw closest to you. This is easiest since you can see it.

Now looking over the top, grab the motor and twist it slightly so you can see the remaining damper hole line up. Insert the remaining screw. Alternating each screw, tighten them down.

Now place your ruler over the two slide rods again. The pulley will be under tension, so carefully raise or lower it until the spacing looks right.

Tighten the set screws in the pulley a little – this is a little fidgety since I did it while in place. But don’t tighten them completely.

Push/pull the build plate back and forth a few times. The belt should not rub on the bottom or the top of the pulley. It’s Ok to have it higher or lower on the pulley – just not so that the belt is being curved by the top or the bottom of the pulley.

Now tighten the set screws all the way – pretty tight!

Plug the motor back in (I forgot to do this first time!).

Add a new zip tie and don’t forget to trim it.

Turn the Mini around, pug everything back in and enjoy how much quieter it is.

Note from girlfriend in other room: “I didn’t even realize you were running it.”  That is how much of a difference it makes! But, once she listened for it she could hear it, but certainly not as loud and annoying with that high pitched Y axis sound.

Worth every penny.

Let me know if you have questions or comments below.

Happy printing!