Robobot hardware
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Hardware
All 3D-printed parts are designed in Onshape and are public. They can be accessed at https://cad.onshape.com/documents/fef8699fcafb8aea780c8981/w/ce38e7fdd6cf8533b65e2c3c/e/eefdcf481faf2a4b03f5058c A browser-only CAD tool.
For students, a free account can be created at https://www.onshape.com/en/education/
All items can be exported (in e.g. step format) for import in other CAD tools.
Mounting holes
The hardware is 3D-printed plastic (except for the electronics and screws)
All 3D printed parts have holes for mounting additional parts. These holes have:
- Individual hole distance of 1cm.
- Hole diameter of 2.5mm, intended for 3mm plastic screws.
- Plastic thickness is 6mm in most cases.
Screws
Screws for plastic (PT screws)
Mounting items on the 3D-printed thermoplastic should use plastic (PT) screws.
Plastic (PT) screws:
- Cut into the plastic with a sharp thread.
- Gets locked into the plastic.
Plastic (PT) screw selection:
- Pan-head 2.5mm for PCB mounting, length 8mm, Torx 8IP/TX8.
- Countersunk 3mm length 10mm, TX8, for the most plastic-plastic mount, where head height is important.
- Pan head 3mm, length 10mm, TX10, for the most plastic-plastic mount, with space for the head.
- Pan head 3mm, length 16mm, TX10, for servo arm 'axle'.
- Countersunk 3mm, length 25mm, TX8, box lit 'bearing' and camera mount.
A typical pan head screw for thermoplastic.
Screws for metal
Mounting of motors and other metal parts should use screws for metal.
Metal screw selection:
- M3 pan head (For servo horn, 16mm, Torx TX10)
- M3 countersunk (For motor mount, 12mm, Torx TX10)
- M5 bolt (For the main wheel fastner, 16mm, Hex/Umbraco 4mm)
- M5 nut (For the main wheel fastener).
- M6 bolt (Castor axles, length 50mm, Hex/Umbraco 5mm)
Axles
Castor wheel axles are made from
- 2mm piano wire, length 25mm (e.g.: https://www.hobbydirect.dk/shop/modelskibe-af-trae/tilbehoer/piano-traad-pianotraad.htm).
NB! This is hardened steel and can not be cut by normal cutting tools, use e.g. a Dremel cutting disk.
- 6mm bearing flange for castor, IGUS iglidur M250 flange bearing MFM061010
