My astronomy project:
Design of a 3D-printed filter wheel

Content:

1. CAD design of a filter wheel
2. Chassi
3. Stepper motor
4. Gears
5. Shaft and Roller bearings
6. Home position sensor
7. Lid
8. Off-Axis guider
9. To be continued

Note:
I take no responsibility or liability for what are written here, you use the information on your own risk!

1: CAD design of a filter wheel

Is it possible to 3D-print a filter wheel ? I have read about others who have tried to do this, but plastic materials is problematic. Many of them use a manual filter wheel casted of aluminum and put a motor on it. But I just have to try to 3D-print all of it. This one has four 50 mm circular unmounted filters and will be used with a full frame camera.

I will built it around this open source project, myFilterWheel:

• https://sourceforge.net/ projects/ myfilterwheel-ascom-diy/(myFilterWheel)
• https://altushost-swe.dl.sourceforge.net/ ... myfilterwheel ... Documentation.pdf(myFilterWheel documentation.PDF)
• https://github.com/ Blueshawk/ Rayz-indi-wheel/ blob/ master/ FilterWheelZX-xagyl.ino(driver that maybe works or can be modified to do it)

It's designed for Windows with ASCOM drivers, but there is some work going on to build an INDI driver for Linux.

Filter wheel:

I have started with the wheel that hold the filters. It will be used to a full frame camera and it need at least 50 mm unmounted filters. To not have too big diameter I limited it to 4 filters. I will use this wheel with three narrow band filters, or red, green, blue and H-Alpha. The thickness of the wheel above is 6 mm but later increased to 8 mm. M3 nylon screws hold the filters in place, a circular frame of 1 mm center them in correct position.

Three M3 screws which heads hang over the edge to the filter and hold them in place. These ones only for a test, they will be replaced by screws made of nylon and have a length of 4 mm.

A more clear view of how the filter holder hole looks like. A one mm rim at the bottom that the filter can rest against.