Since my design habit is to minimize the use of supports and hardware during printing, most designs use tolerances to directly connect. Due to the printer's tolerance and the relationship between different printers and materials, there are inevitably some cases that are too tight or too loose. Some places may need to be polished or tightened with double-sided tape.
Requires 4 686 bearings and 3 106 bearings, a little bit of badminton racket wrap, and a little bit of double-sided tape. For specific installation methods, please check the video on Bilibili. Below is a brief installation guide:
Since it is designed to be printed without support, this separated structure was used when making the rotating shaft. Align it with the snap-in and put it in. Rotate it slightly with pliers. It's tight enough, don't use excessive force, otherwise, it will be twisted.
Then snap on this 686 bearing for later use.
Next, we use these 2 106 bearings:
One is snapped here. The tolerance reserved is relatively small, and you can use tweezers or a screwdriver to help.
The other two are the same way, snapped here.
Let's install the gear.
This drive gear has a relatively small tolerance, and it needs to be inserted and then pulled out to test before installation.
Then install it in place like this, leaving the suspended part alone.
The bevel gear also needs to insert and pull out the shaft first. Sometimes, due to the shaking of the printer, the middle part will be a little thicker. Therefore, if necessary, it can be polished slightly. The method is very simple, sandpaper can be used, I usually use pliers to rub it a few times.
Then press in the third 106 bearing, press it to the bottom as much as possible, and then put in this small C-shaped ring, which is used to limit the position.
Finally, connect it with the bearing and turn it to test.
Then we press in the installed rotating shaft. Here is a reference to the design of Bambu AMS. In order to limit the position of the rotating shaft more accurately, the design has been modified here, and a small step has been added. Therefore, when installing, it should be slightly bent outwards.
Then we put the support frame into the opened dry box. And then connect with this shaft sleeve. What are these two small spacers for? Because the side of the dry box is not completely vertical, there is a slight angle, so you can choose to install this spacer, which can make the interface smoother.
If you have high requirements for sealing, you can use glue here or add some TPU gaskets.
Then install the detachable knob and that's it. Last time, a netizen suggested using a handle, a good idea, but I am too lazy to design it, haha, mainly because there is limited space here. This time, the size of the knob has been increased, which feels good to use.
Could you please design a version that can be printed on the A1 mini?
The A1 mini's maximum print size is 18cm * 18cm. Although it cannot fill the entire bottom of the 5.8L rice bucket, it should be possible to compensate for the size difference by extending the shaft of the handle's rotary knob.
Alternatively, the positions of the two axles could be shifted to one side, but this may require adjustments to the size of the gear mechanism.
During usage, I noticed an issue: the passive shaft without a gear and the active shaft with a gear are not symmetrical about the central axis of the drying chamber bottom. Therefore, if the filament spool has a larger diameter, it will interfere with the bucket wall on the passive shaft side, making it unable to contact the passive shaft. In this case, the friction force during the spool rotation will increase.
It is recommended to design both shafts symmetrically about the central axis of the drying chamber bottom to accommodate spools of different diameters.
My previous suggestion of offsetting both shafts to one side is also not recommended due to this issue. To adapt to the A1 mini print size, the design needs to be modified, and the shaft of the hand-turning knob needs to be extended.
While this design was not implemented, the drive shaft can be pulled out a small distance if needed, separating the two gears, because it's simply a tolerance fit between the drive shaft and bearing. However, it can also rotate along with it, and this small amount of resistance is negligible for the extruder.
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