Supporting the material to be plasma cut

Many CNC plasma cutting machines include a one-piece material support surface. This can either be a welded gridwork made of vertical steel slats, or a number of pointed support points welded into a single structure.

The disadvantage to these support surfaces is they must be replaced in their entirety when even a small part of the cutting surface becomes unusable. Surfaces that support the material with points, rather than slats, tend to promote the tipping up of cut pieces, which can easily block the path of the torch.

Work supports are sacrificial, in that they become destroyed by the plasma torch over time. It is vital that you use a support structure made of individually replaceable steel slats. That way, you spend only a few dollars to make the surface like new, rather than hundreds of dollars for a complete new support grid.

This page shows you how to quickly and economically fabricate a support table with individually replaceable 3/16" x 3" steel slats.

Appearance of material support surface using 3/16" x 3" slats:

Method of supporting slats:

Weld a length of 1/2" x 3" cold roll bar to both sides of the frame as shown above. The tops of the cold roll bar should be flush with the bottoms of the side pieces of 3" square tubing, and with the tops of the end pieces of tubing.

Cut two lengths of 3" x 1" x 1/4" thick angle iron the same length as the 1/2" x 3" bars, and tack weld them to the insides of the bars. The top of the 3" leg of the angle iron should be flush with the top of the 1/2" x 3" bar.

The purpose of spacing the angle iron out from the frame sides with the cold roll bar is to permit you to insert the slats without interfering with the gear rack assemblies on both sides.

You will tack weld the tops and bottoms of dowel pins to the 8' lengths of shallow angle iron, as shown above. Space each pair of dowel pins 3/16" apart with a short piece of 3/16" thick hot roll bar. Space each set of dowel pins so the material support slats will be on 3" centers. Use a machinist square to ensure that the dowel pins are vertical.

You now have a sturdy material support surface with individually reversible and replaceable vertical steel slats. This is superior to any kind of one piece support surface, and can be fabricated in a couple of hours' time at a cost of less than $100. The use of dowel pins that are already the correct length really save fabrication time. The dowel pins sell for about $40 per hundred at MSC, McMaster-Carr, and other industrial supply houses.