Several years ago I found a run-down of best value linear guides... of course it wasn't black and white, but several people made great points.

I can't find it anymore... and I have some additional parameters, so I thought I would ask again.
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I am specifying linear guides/ballscrews for sealed (IP54) stages on a 12"x12"x12" laser weld machine (no tool loads).
Simultaneously, I'm specifying linear guides/ballscrews for sealed (IP54) stages on a "Desktop" 12"x12"x12" cnc machine (for aluminum).
I would like to use the heavier CNC (tooling load) bearings on the laser stages if pricing permits... laser customers may appreciate some over-design and pay for it.

I have been studying IKO, THK, HIWIN, MISUMI, NB, THOMSON

As a benchmark, I use 20,000 hours maintenance free AeroTech Pro115 stages. These stages are about as premium as it gets... for precision, light duty, ballscrew stages at least.


Questions:
1) Do I need stainless steel everything to be 20k hours maintenance free ?
2) Do I need self lubricating like E2 on HIWIN to be 20k hours maintenance free?


3) Is there a hierarchy in linear bearings.... a "can't go wrong" with X bearing company? Or are they simply a commodity now, where delivery times and good sales guys are the determining factor?

OH, and unfortunately.. as much as I would like to use a great value knock-off... these systems are for a pretty picky customer... not an option.

Anyone have experience and an opinion?

Jamison