July/August 2018 - Advances in air plasma systems are making metal removal faster, easier, safer and more economical. The systems are smaller and more portable than ever, consumables last much longer, and they feature smart technology for ease of operation and consistency.
But challenges remain. From cutting metal in hidden or hard-to-reach areas to precisely removing a weld without damaging the surrounding metal, and removing temporary attachments without a significant amount of grinding, innovations are helping to overcome common challenges. New plasma nozzle technology can tackle those challenges while also increasing productivity and lowering operating costs. Used correctly, the technology can lead to a safer work environment.
Here’s a look at four tools and applications to keep a metalworking shop on the cutting edge.
1. Getting flush-cut finishes
In most large fabrication projects, lugs and other attachments need to be removed using oxyfuel, carbon arc gouging or traditional plasma cutting tools before prepping the surface for finishing. It can take a lot of time to cut or gouge away the welds that hold these attachments to the base metal and then grind away any residual metal. However, new consumables designed to bend the plasma arc as it exits the torch and provide a flush cut can help remove attachments more quickly and easily.
An angled nozzle bore design and flat guiding shield can cut closer to the base metal, usually leaving less than 3/16-in. of residual material on the base or workpiece. This, in turn, reduces the necessity for grinding and repair work. In addition to time savings and safety benefits, the 45-degree angle of the arc allows for lugs and attachments to be removed with a flat bottom, increasing the chances that the lug or attachment can be reused.
2. Greater variety equals greater control
The depth and width of a gouge is controlled by adjusting the angle of the torch to the metal, the speed of travel, the amount of arc stretch and amperage level. Technique, however, can only get you so far, which is why consumable choice matters. A wide arc from a gouging nozzle combined with a larger bore from a plasma system and with high output current will result in a wider gouge, compared to an arc from a nozzle with a smaller bore from a plasma system with a low output current.
Today, gouging consumables are available that allow for aggressive metal removal for deep gouge profiles and extreme metal washing applications; for more controlled metal removal, ideal for achieving shallow gouge profiles or for light material washing applications; and for precise removal of small amounts of metal with great accuracy at a very low output current.
3. Longer length for tackling tight spots
A common challenge during manual plasma cutting is positioning the handheld torch in a tight location and still being able to see the material being cut. Often, once the torch is in position, the metal and torch head are obstructing your view of the workpiece.
Consumables that are a few inches longer and narrower than traditional consumables provide greater visibility, which, in turn, allows for a more precise cut or gouge. Both can reduce or even eliminate the amount of grinding necessary. This consumable design also is helpful when performing close cuts to the web on a beam. It provides increased reach and access, making this type of cutting much easier and more accurate.
4, Gouging from a distance
At the opposite end of the spectrum are those jobs when precision doesn’t matter as much as productivity, safety and comfort. Whether that includes scrapping applications or cutting metal overhead, handheld torches are now available with a variety of different head angles and lengths. These torches, which can range from 2 ft. to 6 ft. long, are easy to use and offer safety benefits that can reduce operating costs.
For example, these long torches are suitable for cutting samples of rolled steel without slowing down the production line for an array of scrapping applications and for applications that put workers at risk of being struck by falling metal. The longer torch also has helped increase productivity and reduce incidences of injury and fatigue in metal scrapping applications.
Consider upgrading your plasma tools to keep pace with these technological advances. It may seem easier to stick with older, more traditional fabricating methods, but improving your tools will make metal cutting and gouging faster, easier, safer and more economical, not to mention less stressful and more enjoyable. After all, accuracy and precision with your fabrication is well worth the investment.
Harry Mellott is a senior project manager at Hypertherm with nearly three decades of marketing and communications management experience.
