Plastic versions of aluminium extrusions?

[Infraviolet]

Does anything like this exist? What would be the best search terms to find it for sale. I'm after something lighter weight, and cheaper, than aluminium extrusion for low-stress structural frames (holding lights, frames for little thermal enclosures round 3d printers, structures within robots...), with the same sort of groove structure and shape which lets you fit T-nuts in the grooves and mate on to the kinds of corners and other attachments you can use with aluminium extrusions. Thanks

[Kleinstein]

There are also extruded plastic profiles. Plastic windows are made this way.   There are some standard plastics profiles available, but usually not for structural purpose, more like decorative, sealing, or holding cables and the like.

If price is an issue, wood may be an option.

[radar_macgyver]

McMaster in the US carries a variety of extrusions in a variety of materials, including UHMW, PVC, PP and PTFE. They aren't particularly strong; for strength consider one of the composite materials (FR4 (aka Garolite), structural FRP or carbon fiber - all available at McMaster).

Specialty plastics vendors will carry these, though it seems like you can get some types on Amazon:
https://www.amazon.com/Outwater-Plastics-1936-Bk-Styrene-Moulding/dp/B07MCJ763G

I searched for "UHMW angle"

[thm_w]

Its an interesting idea, but what sort of budget? 2020 aluminum extrusions can be fairly cheap if you have a local supplier.
https://forum.makerforums.info/t/has-anybody-ever-seen-plastic-2020-t-slot-extrusion-for-sale/46310

For the 3D printer enclosure, you can print corner brackets and use say wooden dowels, or posterboard, to form the walls. Lots of ideas out there.
https://themechninja.com/10/diy-3d-printer-enclosure-budget-friendly/