Best rails position on frame in a dusty workspace

Hello,

I am currently designing my first plasma table with a 2x1m cut area.

The thing that questions me the most is the problem of dust on rails, and more generally how to protect rails.
I plan to use Hiwin HG20 or 25 rails, but I worry that dust and cut projections can wear rails or carriage. I think about put rails on sides, or under sides (suspended gantry) but this only partially resolve the issue.
My workshop is very dusty (because of lot of different activities), and I do not want to clean my rails before each job.

What could be your advices / hints for this point ?

Precision : this table will not be used intensively. Only few times a month. And I have already made an investment on a Powermax 45xp with CPC port, a hand torch and a mechanic torch.
And I have already read those really nice posts :
forum.linuxcnc.org/plasma-laser/35349-cn...fo-and-guide?start=0
forum.linuxcnc.org/show-your-stuff/38547...plasma-build?start=0

Thanks in advance,
Have a good day.

I would recommend placing the rails as far away from the cutting area as possible. Mounting them on the side of the gantry will work but I would advise to cover the top of them with a section of flat bar.

On the large industrial machine I built, I mounted them on the side of the gantry but water and dust got onto the linear bearing and destroyed them. I ended up making a cover plate to stop dust and water getting on them and they have been going for a few years in a extremely dirty environment.

I am thinking to use something like that :

It has the advantage to serve as fairing in addition to dust protection. But I am afraid to have to use Hiwin dust accessories nevertheless. Those damn accessories that curb displacement...

What you have drawn should work well.

Ok, thanks for this reply image missing /media/kunena/emoticons/smile.png

I think you need to improve the upright now. There are a lot of inertial  forces from movement on the gantry that will apply bending moments around your proposed gantry plate anchor points. You can't afford to have sideways movement on the gantry rail as accuracy will suffer.