modified grates

[cutterguy]

I am thinking of modifing the grates on my Plasmacam. Pcam uses a system where the metal rests on small spikes on the grates. I don't like this system because it is very hard to slid material across it. Also with the grates on a 4" or 5"grid I have trouble with small parts falling down into my water table.
How do the systems with just flat bars work? How close together are the bars spaced? Does a system like this affect cut quality on the bottom side of the cut parts.

[jimcolt]

Flat slats are generally the best for plasma cutting applications....as the smaller parts have less of a tendency to tip up and cause a collision. The PlasmaCam machine design was centered around ease of use....so their pointed slats made it easier for new users to locate the material and the part program on the cutting machine.

Jim Colt Hypertherm

[weldguy]

Flat grates work very well. I recommend using 14 guage, the less surface area the better when the torch passes over the grates as its cutting your plate. Just have a bunch of strips sheared up. Thicker grates will cause your plate to stick to it more when the torch passes over it and will leave more of a mess on the backside of your plate.

Also bowing the grates in an arc helps if your in a situation where you are cutting inline over the grate you only contact it with the plasma arc in a couple spots rather than buring over the grate all the way across making a mess of your part and the grate.

weldguy

[Roger_F]

I'm actually building a Plasma table now and I'm at the point of deciding on the style of grate to use. I was thinking the points were better, but you guys are saying flat slats are best, Interesting. Flat slats are easier anyway. Any recommendation on how tight to space them? How about the depth, using 14 Gage flat stock, how wide should the slats be to not sag on a 5' span? Any advice is appreciated!

Just so you know where I'm coming from. I've never used a Plasma table before. I have a Hypertherm Powermax 1000, but I can't cut a shape by hand to save my life. I've done a Bridgeport CNC conversion before, so I have all of the Computer & servo drive experience.

Thanks!

[weldguy]

I would go with a 2.5-3" wide strip for your 14g and space them 3 inches apart or so. Bowing them is a good idea also rather than leaving them straight.