If You Must Process Plate in Any Way, You’re in the Right Place!
Plate processing (sometimes referred to as “thermal cutting”) used to be, in the old days, only done on a “burn table.” A large fabrication company or shipyard or steel service center would set up their job on the table and let her fly. A burn table is nothing more than a bunch of oxy-acetylene torches lined up in a row, attached to a make-shift bridge. These oxy-acetylene torches (welding torches) are the same torch an individual welder would use in his or her day-to-day work at the large fabrication company. Either the bridge (for want of a better term) would move, or the table would move, and the torches would begin to cut the plate. Initially, the first tables would only burn in a straight line. It wasn’t long after the conception of the first CNC controllers that companies who had burn tables began to retro-fit them so they could burn parts with up to 3 (and sometimes 4) axes. This was a great improvement over how burn parts could be cut from a solid plate in previous years. Prior to burn tables, single or multiple welders would descend on a piece of plate steel and cut the parts one-at-a-time by hand, usually right on the floor. So, there’s no contest between burn tables and cutting the parts on the floor one at a time. Hurrah for the burn table! But wait a minute, there’s a “fly in the ointment.” Burn tables have their downside. The most difficult residual effect of using a burn table is the inadvertent flame hardening to the steel plate you are cutting that takes place when you use an oxy fuel torch. Burn tables radically increase the hardness around the edges of the cut piece, making follow-on machining operations more difficult. Additionally, burn tables are not particularly kind to the environment, in that they tend to smoke at startup, and also when the table is idle. So, what technology is going to come along and unseat the old burn table, we wonder.…
Enter the Era of Plasma Cutting. Will the World Ever be the Same?
Plasma table cutting, simply defined, is the action of applying a super-heated electrically-ionized gas from the plasma cutter to the piece being cut. You simply ground any conductive metal, like steel, aluminum, copper (or many other conductive metals) to the plasma cutter and start cutting. One of our salesmen shared this observation: “I don’t know about you folks, but I remember the first time I saw a plasma cutting machine in this one company. It was beautiful, brand new, and most notably it was big! The cutting I witnessed that day was the fastest plate processing speed I had ever seen. At the time, I represented a manufacturer of one of the best and fastest plate band saw machines around, and I could tell in seconds that there was no contest between band sawing and plasma cutting when it came to speed.” Plasma cutting equipment is available today from very light and compact units that can easily be carried by one person, to the massive CNC plate cutting machines at work in major fabrication operations. Of course, the power differs greatly from the walk-around unit to the huge plate processing machines. The small, light-weight machines work really well in an automotive environment where the metal thickness rarely gets to be more than 10 gauge. In contrast to those handy, light-weight machines, the large plate processing plasma cutters can cut metal as thick as 150 mm or 6 inches thick. How the plate plasma cutter is equipped — since it could be an older N.C.-controlled machine or a newer version with a CNC controller cutting up to 3 axes — will determine how the machine functions. A third axis was introduced so the cutting head could cut a taper from top to bottom, while the head pursues a 2-axis cutting path. Let’s recap the plasma's main attributes:
- Size. Depending on the machines size and capacity, you could process up to 6 foot by 12 foot sheets of steel, aluminum, copper, brass or any other metal sheet or plate that conducts electricity.
- Speed. In comparison to other plate processing techniques, plasma has proved to be much faster cutting and less cost per hour to run.
CNC plasma tables are frequent visitors to Bud's Machine Tools used machinery section, and we have sold many of these used machines along the way. (Including your next one!)
