building the table with exhaustion system

[Alex S.A]

Hi all,

Does anyone have experienced to build a plasma table with exhaustion system to avoid the fumes and smoke that come from the process? If so how did you start to build ?

Alex S.A

[gl1200a]

We have a TrackerCNC 4 X 8 table and originally built a downdraft table. We got 10" ductwork from Menard's and a free squirrel cage / motor from an old home furnace at a local HVAC dealer.

Installed the motor internally in the bottom of the table (after we put a steel floor in the farmework) and cut a 10" hole out the side. It worked so-so until the air bourne slag clogged the squirrel cage bearings enough that we had too 'hand prop' the fan to work. And, unless the cutting area of the table is fully covered, the exhaust wouldn't suck enough to exhaust all of the smoke. When we would use a partial piece of steel we had already cut out of we would have to cover the open grates so the exhaust would pull from the cut area and not the open grills.

We then went to an overhead (5 X 10) hood with another squirrel cage fan / motor up inside connected to the same ductwork and then added a weling curtain down to within about two feet of the table top. We got galvanized side pieces of about 10" high in a 5 X 10 foot configuration and put a 20 ga. covering over the top and hung it from the ceiling steel rafters with chain. Connected the same ductwork. The exhaust duct was originally in a 'Z' shape from the base of the old downdraft setup up along the side of the CNC table and out the upper wall near the ceiling. We took out the 'Z' and the duct now goes straight out the side of the overhard hood and out the upper wall.

This seems to work extremely well and we have no smoke or air bourne particles in the shop at all. We're real happy wit this setup.

[Graybeard]

My plasma machine is located about four feet from an exterior shop wall. I cut a hole in the wall at table height and installed a "whole house fan" that moves smoke and dust outside. The only problem is it also sucks the heat out of my shop - not a problem most of the year and probably not a problem in Braziil.

I followed up by installing a water tray with my work support slats in the tray. I burn with water touching the steel and sometimes even on top of it. I get better burns and less warping, less dross, and no dust, fumes or smoke. Also, I can pick up the pieces immediately after the cut. The tray will get rusty unless you mix borax or washing soda in the water.