Cutting steel and other manly materials part 2

The warehouse at Klein Steel is relatively unimpressive to the untrained eye. Certainly, large pieces of steel, big cranes, and loud noises have some inherent impressiveness, but the devices that sound like they leapt out of a science fiction movie like the plasma torch and laser, are not so obvious.

To make an analogy, big trees are impressive, but the ecologist appreciates the forest on deeper levels than the layman. As one learns more about the warehouse and the operation taking place there, one gains a deeper sense of awe. (ugh, that analogy sounded better in my head, I apologize.)

All of the cutting tables are large devices with very small essential pieces, namely the torch tip or nozzle. Steel slides into the laser's maw and barriers rise up for safety. Once the laser starts actually cutting, one has to move right up to the glass to see it work. A large robotic arm that is truly straight out of a movie (metallic whirring and hissing included!) directs the laser with machine precision. A red light shines out of the small tip at the end of the arm. The arm makes a small circle. The light disappears and a small circle of steel falls out. Just like that.

The laser operator, "Laser Bob", remarked that the laser can cut steel, but not paper. This is an exaggeration, but he makes an interesting point: reflectivity of the material being cut is very important. Too much reflectivity and the laser will bounce back into its tip and over heat the nozzle.

Each of the cutting tables has its own unique problems. The "burn tables" as they are called, also have problems with things blowing back into the torch heads, but instead of light or flame, what blows back is liquid steel. The operators of the burn tables have to make sure that the material has been sufficiently heated all the way through so that when cutting begins all the material is blown down and through instead of being pushed down against insufficiently heated steel. In this case the burned steel bounces back upwards and can lodge on or in the torch head.

It is inaccurate to say that the steel is pushed. Even the word "cutting" is slightly inaccurate. Torch nozzles have many small fuel dispensers arranged around a central oxygen dispenser. The torch dispenses the right ratio of fuel and oxygen to sustain a flame, which heats the steel. When the steel is hot enough it will actually ignite and burn under the right conditions. The additional condition needed for steel to burn is a high concentration of oxygen. When the steel is hot enough the operator turns up the oxygen and the steel burns like paper. So the operation is cutting, but it is cutting via burning. They are called burn tables for a good reason.

One of my favorite tables on the floor is the water jet, which is operated by a guy named Mark. His nick name is "Water Mark" (pun intended). This table is cool and extremely Zen.

I'm told that in Hong Kong (I think it was Hong Kong) there is a game similar to the West's "rock, paper, scissors," but originated independently. It is called rock, bird, water. It works like this: rock beats bird, bird drinks water, water beats rock. From high school science we know that over time water can carve rock. Exhibit A: any number of rock formations in the American southwest. The water jet cuts steel with water flung out of the nozzle with a velocity four times the speed of sound.

The material being cut is positioned on slats above a pool about four feet deep (three feet of water and another foot of sand). The water jet runs its nozzle over the material with a loud hissing and a little bit of innocuous spray. The four foot pool is needed to cushion the force of the water jet and it bubbles like a turbulent pool in Yellowstone (it's even the yellowy-brown of many of those natural pools).

I was disappointed to learn that the water jet does not cut solely with water. I apologize for tarnishing some of the water jet's mystique by giving this away, but fine garnet is infused into the stream of the jet and is responsible for much of the cutting.

While on the warehouse floor, I also observed a lot of autoCAD (automatic computer automated design, it's doubly auto!) drawings which are translated so that the machines can cut out the shapes drawn on them. A decent amount of math goes into the process. AutoCAD-ing requires many skills from high school geometry: shapes, degrees, rotations. There is even some higher math used out on the floor. Tiling theory is used to tightly nest shapes to be cut on a single piece of steel to minimize waste. Much of this is taken care of automatically by the autoCAD program, but other times the operator is responsible for making sure all the shapes to be cut fit tightly together on a sheet of steel.

The end.

I couldn't think of a conclusion of any kind. Meh?

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