No printer yet - but I have queries re materials

I am considering a 3D printer as an option for creating some plastic slides that will slide smoothly on an aluminium profiles rather than machining them out of UHMWPE as I do at present.

I have two questions:

- Can a printer print a solid model ie like a plastic bar of 20mm x 20mm cross section (lenth will depend on the size of printer I guess but would need to be abput 100mm long).
- what are the most durable materiels that can be used in a printer ie can take some wear and tear as the slide along the profile.

Anyone care to advise?

Thanks

printing size - not an issue - pretty much every machine on the market can do that size.

Material wise. you have a choice. Sounds like pet-g or ninjatek armadillo (rigid polyurethane) would be your best bet.
Though you might be surprised at how well pla works and lasts.

You could also go with nylon, but that tends to be fairly flexible. Not sure if that's important.