Plasma cutters have been used for many years to cut dense materials like metal. However, current plasma torches are very expensive and difficult to keep cool because of the intense heat involved. Image #3 is a computer generated model of a new and improved plasma cutter that is less expensive and solves many of the current cooling issues.
The picture shows the most important features of the innovative design of the plasma torch. The glowing slits that radiate around the picture let in ionized gas into the internal chamber. Inside the torch the electrodes are surrounded by a magnetic field at both ends of the torch. The change in voltage between the two electrodes creates a bolt like lightning that jumps from one electrode to another, and this bolt heats the incoming ionized gases to close to 10,000 degrees Fahrenheit. These gases then come out of the nozzle on the torch and cut the metal with a very precise cut. When the bolt hits the ionized gas it makes the gas spin which is a major reason the plasma torch is so powerful. The rings in the picture are the first pulses of ionized gas before it pops an arc. The innovative dome shape sends pulsating rings of ionized gas to the center electrode. Because of the pulsing plasma design, this torch cuts energy usage down from that of the regular plasma cutters.
The mirrored effect that is seen in the picture is caused by a thin layer of water on top of a metal sheet. The water is used to cool down the metal. The reason the design needs water is because the heated charged gases coming out of the plasma torch that cuts the metal are at about 10,000 degrees Fahrenheit. At these temperatures, splattered pieces created during the cutting process would put holes in the rest of the smooth metal sheet where the shards hit it. The water cools the shards down extremely quickly and keeps them from pitting the smooth metal surface. The innovative dome shape of the torch keeps the metal shards from splattering onto a piece of the metal where there is no water.
The main reason the engineer was asked to build the plasma cutter in this design was to cut energy cost, make it more efficient, and more powerful. The shape and configuration of the electrodes and the curved shape of the dome which directs the incoming ionized gases helps to achieve these goals. The ionized gases circulate within the dome and get reused, cutting the amount of incoming gas needed and reducing the electrical consumption required to ionize the gas. The engineer spent many months of research and development to make an efficient and commercial product. Several months were spent in the lab testing different plasma torch designs. Different shapes, voltages, magnetic fields, gas flow, materials of construction, and frequency of electrical pulses were tested.
Some of the engineering principles that are included in this design are electricity, design, and mechanical. The electricity principle is needed so that the torch can get the perfect voltage jump between the electrodes. The design principle is needed so that the parts of the torch won’t melt under the intense heat. Lastly the mechanical principle is needed so that all the parts of the plasma cutter work in the right order to insure maximum efficiency.
Most plasma cutters work well, but this new innovative design will revolutionize the plasma cutters. It is more efficient and costs much less to use. Also it solves the problems of how to keep the cutter cool under intense heat conditions with less damage to the metal sheets that are being cut. Because plasma cutters are a major expense for most companies, with the new design more companies will be able to afford the plasma cutter to help with industrial work. As image #3 shows this unique plasma cutter has many new engineering features of the latest technology in the plasma cutting industry.
The winners of the 2017 EngineerGirl Essay Contest have been announced! NAE President C. D. Mote, Jr. said, "Students’ devotion to protecting endangered animals is always inspiring to me, and their doing so through engineering, which is about solving problems of people and society, is doubly so. Congratulations to the winners!" Check out the link below to read the wonderful essays.