Hydra AMS - Improved Rear Rollers

Update August 22, 2023

Rollers updated to version 1.3, offering slightly increased tolerances against the roller slots. Thanks to @AdamL for the feedback!

Update August 5, 2023

The rollers were redesigned and updated to version 1.2. I've found in testing that tapering them from larger diameter in the edges to smaller in the middle will do a better job of forcing and keeping the spools centered than the old design. There are still three sizes, the largest one (16.5 mm) is similar in size to the stock roller while the others are smaller to allow for larger diameter spools.

It might be a good idea picking up some extra 693-ZZ bearings (link in the BOM below) and have a set of each so you can quickly switch rollers for normal and smaller spools.

About

This is a set of improved rear rollers developed for Hydra AMS. It will also work with the standard Bambu Lab AMS but I've only tested it briefly. The diameter of the roller is around 2 mm less than the stock rollers, allowing larger diameter spools without having to use a lid spacer. It's also slightly wider than the stock roller. There are also other sizes available depening on your requirement, see more below

Another improvement is that the roller bearings are moved from sitting outside the roller on a thin 3 mm plastic pin to being installed in the actual printed roller with an M3 socket head screw for strength.

With the current Hydra AMS (1.08) and the standard rear rollers, the maximum diameter of the spools with the lid closed is around 202.5 mm. With these improved rear rollers you can use up to around 203.5 mm spools with the lid closed.

Be aware that smaller 1 Kg spools than standard, say 190 mm diameter, will rub against the bottom of the Hydra AMS if you use the rear-most position of the rollers. For these you can either use one of the larger rollers or use the adjustable socket head casings in the raised position:

• socket-head-casing-adjustable-1.3.3mf

BOM - Bill of Materials

You can print the parts in just about any filament you like. You need some M3 hex socket heads (around 25 mm is fine, shorter or longer will also work). I usually recommend this kit which I've had for years and use for most of my designs and builds.

• 440 pcs M3 Hex Socket Head Cap Kit

If you do not want to reuse the stock roller bearings or want a spare set / different sized rollers, you can buy some extra bearings:

• 693-ZZ bearings

Which should I print?

The stock rear rollers have a diameter of around 16.10 mm near the edges. Depending on if you want to raise or lower the spools, print the appropriate roller:

Example A) You have a large diameter spool (202 mm). Using the standard rear roller it rubs against the roof of the AMS. Use a smaller rear roller (try 13.5 mm or 14.5 mm).

Example B) You have a small diameter spool (190 mm). Using the standard rear roller it rubs against the bottom of the AMS. User a larger rear roller (try 16.5 mm or 17.0 mm).

Print Settings

Print the parts in the direction I have set them, no supports are required. Use random seam. Print a set of one rear roller and two socket head casings for each roller you want to replace:

• rear-roller-for-hydra-ams-14.5mm-1.3.3mf
• socket-head-casing-1.3.3mf

If you use a stock Bambu Lab AMS or an earlier version of Hydra AMS (1.06 or earlier), print this instead: rear-roller-for-bambu-ams-14.5mm-1.3.3mf

How To Use

First, carefully remove the bearings from the stock rear roller. You can use pliers to pull them off:

Next, press in the bearing into the printed part, one on each side:

Next, slide in the M3 socket head into the casing and the roller:

Now you can install it in the AMS:

If you need to remove a bearing from the roller you can use a 2.5 mm hex tool, insert it then put a little pressure by twisting to grab the center ring then pull straight out:

Improved Rear Rollers - Optional for Hydra AMS.