When trying to work with a CNC cutting machine, there is a manifold of good reasons why you should veer away from the use of a dry or downdraft table and take advantage of a plasma cutting table instead. Acquiring it is less expensive and will never necessitate for a dust collector to be around. Additionally, it significantly helps in reducing noise, minimizes heat distortion, eradicates arc flash, and is also helpful in keeping your parts cool. By now, it may well sit as an older type of technology, but relevant amounts of reliable CNC plasma cutters for sale, as well as the oxy-fuel type of cutting machines, still abound the market and most of them are still sold with water tables.
The Basics of Water Table
Structure-wise, some tables work like a tank. They are filled with water, and on top of them are burning bars. However, this would not accord to you the full benefits of underwater plasma cutting. Let us tackle about a water table type that comes with an adjustable water level. This type of plasma cutting table allows you to submerge your plasma torch and the plate underwater.
Constructing this type of cutting table is pretty simple. You just need to build a large chamber into the table, under the steel tray and burning bars. The chamber inside the water table needs to have a couple of openings along its bottom edge. This feature will allow air to be trapped inside it, remember how an upside-down bowl submerges. Pretty much it works that way, too. Then, if you will let the air out, or by putting some air into the chamber, it will render the water in the table to go up or down.
Its water level controls are most of the time equipped with an air supply valve. It should come with an air supply valve that takes charge of handling compressed air that is going in and out of the chamber. These valves are simple ball valves which you can operate by hand. In the case of the solenoid valves, your CNC equipment can control them instead.
By closing the release valve, the water in the table is raised. This action will eventually render the supply valve to open as well. Compressed air will be pushed into the chamber and force the water through openings located at the bottom part of the chamber. This will bring the water level to rise. Soon after the desired level of water is reached, the air supply valve will close while the air release valve will as is, closed. This will hold the air inside the chamber, causing the water level to stay up.
Underwater Plasma Cutting
The major underlying reason why we use such kind of table is for carrying out underwater plasma cutting. With respect to the torch design, you can submerge it and still do your cutting successfully sans the need or use of any additional hardware.
But with the newer, more recent versions of oxygen plasma cutting systems that are now equipped with precision plasma capability, there is a need for air-curtain to allow clamping onto the torch. Compressed air is used by the air-curtain to produce a bubble that will surround the torch’s front end. This way the precision arc is rendered secure from the water. There are plasma torches that are not particularly intended for use underwater but can still be used in cutting a plate that is set above water.
In the case of larger tables, even if you have no plans or intentions of cutting underwater, the use of an entry-level CNC plasma cutting table equipped with water level control is highly recommended. It lets you lower the water level so you can have easy access to it when trying to clean up the small parts that inevitably get in the way between the burning bars.