•Plasma Arc Cutting •Critical Evaluation of Pipe Welds •Friction Stir Welding Spherical Parts •Bonus:•Bonus: Thethe Americanamerican Welderwelder

270199.qxd:00 5/27/08 1:01 PM Page 1

April 2008

•Plasma Arc Cutting •Critical Evaluation of Pipe Welds •Friction Stir Welding Spherical Parts •Bonus:•Bonus: TheThe AmericanAmerican WelderWelder

PUBLISHED BY THE AMERICAN WELDING SOCIETY TO ADVANCE THE SCIENCE, TECHNOLOGY AND APPLICATION OF WELDING AND ALLIED JOINING AND CUTTING PROCESSES, INCLUDING BRAZING, SOLDERING, AND THERMAL SPRAYING 270199.qxd:00 5/27/08 1:01 PM Page 36

Plasma Cutting Systems Combine Versatility with Efficiency

BY REESE MADDEN

Many people know that a plasma sys- Processes tem can cut, but far fewer know that it can gouge, or that plasma can cut any type of Plasma is best known as a cutting tool, electrically conductive metal, that it can be but even within cutting, plasma is more used on a track system, or that it can be used versatile than many people realize. With 1 to efficiently cut metal up to 1 ⁄2 in. thick. specialized consumables, plasma systems Their ability to quickly But, in fact, plasma can do all this and more, can be used for drag cutting, cutting with and this versatility helps make plasma a a standoff (particularly useful when cut- perform a variety of truly valuable productivity tool. ting odd-shaped pieces or when trying to When you use a tool more you better access a tight location), or even for get- applications on different leverage your investment, making the tool ting high-quality, very narrow cuts on thin a greater value. And when that tool helps materials. you avoid having to switch back and forth In addition to cutting, many owners are metals in various among various tools, or rely on others to now starting to leverage plasma’s gouging execute certain tasks, versatility translates capabilities. Specialized gouging consum- locations makes into greater productivity. ables are now available for many brands American Fire Training Systems is an of plasma systems. Plasma gouging can be plasma arc cutting example of one company enjoying the ver- used in place of carbon arc gouging and satility of plasma. The company makes is an effective method of removing metal some of the largest steel fire training struc- for weld preparation or for gouging out systems versatile tures in the United States. Its projects, worn or cracked parts for repair or which can range in size from a single story replacement. productivity tools 3200-sq-ft unit to a six-story complex, are Plasma is also an effective piercing used to train firefighters around the coun- tool, whether by hand or on a cutting try. American Fire Training Systems table. Compared to oxyfuel, which re- switched from oxyfuel to plasma five years quires pre-heating before cutting or ago and hasn’t looked back. piercing, plasma is particularly produc- Reed Steffek, the company’s produc- tive because it requires no preheating tion manager, said oxyfuel is used for cer- of the workpiece. tain things, but plasma arc cutting ma- chines “are definitely the tool of choice around here. There’s really no beating the Material Types productivity we get from plasma. Plasma definitely cuts quicker, cleaner, and allows One of plasma’s biggest advantages us to do more.” over other thermal cutting processes is that it can be used on any electrically conductive metal, including mild steel, The Measures of Versatility stainless steel, aluminum, galvanized steel, copper, cast iron, and others. This Plasma versatility can be measured in capability is especially attractive to users many ways. who may encounter many different types

REESE MADDEN is a product manager at Hypertherm, Inc., Hanover, N.H., www.hypertherm.com. 270199.qxd:00 5/27/08 1:01 PM Page 37

A construction worker uses plasma cutting at a job site. A shipyard employee in North Kingstown, R.I., uses plasma cut- ting on a track system.

Material of metals, including farmers, scrapyards, Forms and Thicknesses given metal thickness. In many cases, the metal fabricators/job shops, facility speed advantage of plasma over other maintenance professionals, and others. In addition to cutting any type of elec- cutting methods, such as oxyfuel cutting, Plasma’s effectiveness on painted, trically conductive metal, plasma can also is dramatic. Oxyfuel cutting is, however, rusted, or dirty metals is also attractive efficiently cut many material forms: plate, generally regarded as the superior to these and other users. rod, pipe, beam, and even grating — with method for cutting materials more than 1 The ability to cut multiple metal no preheating required. 1 ⁄2 in. thick. types is a frequently cited reason why Air plasma is an effective tool for cut- The versatility of plasma also makes 1 plasma owners make their initial plasma ting thicknesses from gauge to 1 ⁄2 in. the job easier for American Fire Training purchase. Whether owning a plasma sys- Judging a plasma system’s true capacity Systems because workers can use the same tem enables them to avoid wasting time is not always easy given the lack of con- plasma cutting machine for just about any- and money subcontracting out certain sistency among various manufacturers thing they’re cutting. parts of a project, or whether it simply in how they rate their systems. There is, “We use our Powermax1000’s to cut enables them to avoid wasting time however, a common relationship be- through different types of steel and alu- switching from one tool to another, tween cut speed, cut quality, and cut ca- minum whether painted, unpainted, or plasma’s material type versatility is a pacity: there is an optimal speed for rusted,” Steffek said. “And we’re able to clear productivity enhancer. achieving the desired cut quality on a cut through a wide range of sizes — from

What Is Plasma Cutting?

Plasma cutting is a high-speed thermal process that utilizes an accurately controlled electric arc to cut most common metals. The plasma process uses a small nozzle orifice and high-velocity gas flow to generate a very high-temperature, high-energy-density arc. Plasma cutting and gouging re- quires a process gas, such as air or nitrogen, a DC power source, and consumables, including an electrode and nozzle. Plasma arc cutting systems provide the following:

• Fast cutting speeds

• Application versatility

• High productivity

• Cost-effective operation 270199.qxd:00 5/27/08 1:01 PM Page 38

1 3 ⁄2-in.-thick tube, to ⁄16-in.-thick quarter- easily be moved from point to point, distributor to find a plasma cutting ma- ton steel to thin 14-gauge sheets.” whether in a facility or in the field. Recent chine with these features. engineering developments also contribute to the versatility of plasma. Location “The incorporation of Auto-Voltage™ Applications and Boost Conditioner™ technologies into our Powermax brand of plasma sys- At a macro level, plasma can be used in tems really gives users much greater flex- With a simple change of the torch any number of locations, indoors and out, ibility,” said Dennis Borowy, a principal and/or consumables, a plasma system can from a garage to a shop, and from a factory engineer at Hypertherm. The first-men- switch between manual and automated to a job site. A plasma cutting and gouging tioned technology allows people to use a cutting or gouging. With a straight ma- system can be used almost anywhere that a wide variety of input voltages with no chine torch, a plasma system can easily be process gas (compressed air or sometimes manual linking of any kind, while the sec- connected to an X-Y cutting table. Plasma nitrogen) and energy source are available. ond technology makes it possible for the systems can also be used on robotic arms When hooked to a portable motor-genera- system to extract the maximum amount of or, more commonly, with a track system tor and a portable compressor or gas cylin- power from any given line. for effective long, straight cuts. Many der, a plasma system is truly mobile, mak- With Auto-Voltage™, operators can plasma systems are used in conjunction ing it appropriate for use in the field, on a start a job in their shop, plugged into their with pipe bevellers or with hole-cutting construction site, and in many other loca- regular power source, and finish it in the tools. Plasma systems can also be used tions. Unlike oxyfuel cutting, which requires field, hooked up to a completely different with metal templates or guides for effi- a flammable process gas such as acetylene, power source. Up until about seven years cient replication of cuts. propylene, or propane, plasma systems may ago, this wasn’t possible. People moving even be used in some more highly regulated from site to site had to either make sure environments where flammable gases the same voltage levels were available at Conclusion aren’t permitted. all of their locations, or go through the American Fire Training Systems cited time-consuming process of manually this ability to easily move from location rewiring their system to match the avail- Plasma systems are highly versatile, to location as another reason why it de- able voltage. highly productive cutting and gouging tools. pends on plasma. Boost Conditioner™ technology en- The plasma process’s ability to perform var- “Some of our structures are huge and ables better, more consistent performance ious processes and applications, to operate there is no way we can completely cut and regardless of fluctuations in input voltage. in various locations, and to work on vari- assemble them in one spot,” Steffek said. “We This is especially beneficial for operators ous metal types, forms, and thicknesses do as much as we can at our plant, but a lot in areas with unreliable or low line power. gives it distinct advantages over competi- of time the final cutting and assembly has to The technology also compensates for tive cutting technologies. If you already own take place at a job site. Our work would def- weak or varying voltage on motor- a plasma system, chances are you can de- initely be a lot harder without plasma.” generators, providing improved perform- rive greater value out of your investment Certain plasma systems, especially ance for users in the field. simply by expanding your usage occasions. those utilizing inverter technology, are Since this technology is fairly new, not And if you do not yet own a plasma system, even more portable, and can be easily car- all systems have it. Therefore, if your par- you may find that you can get more done, ried up a ladder, taken on board a ship, ticular situation requires lots of moving in less time, at lower cost by investing in this or used in other tight quarters, and can around, you may want to check with your powerfully versatile tool.N Reprinted with permission from Welding Journal, April 2008. © WELDING JOURNAL. All Rights Reserved. On the Web at www.weldingjournal.com.

Any job. Any metal. In the shop or in the field.

System Powermax 190c Powermax30 Powermax600 Powermax1000 Powermax1250 Powermax1650 Output Current 12A 30A 40A 60A 80A 100A Rec. Capacity 1/8” (3mm) 1/4” (6mm) 1/2” (12mm) 3/4” (19mm) 7/8” (22mm) 1 1/4” (32mm) Max. Capacity 3/16” (5mm) 3/8” (10mm) 5/8” (16mm) 1” (25mm) 1 1/8” (29mm) 1 1/2” (38mm) 30-50% 40-50% 40-60% 60-80% Duty Cycle 35% Voltage 50% Voltage Voltage Voltage Dependent Dependent Dependent Dependent Weight 43 lbs. (20kg) 20 lbs. (9kg) 47 lbs. (21kg) 83 lbs. (37 kg) 96 lbs. (44 kg) 128 lbs. (58 kg)

Find out for yourself why tens of thousands of businesses including American Fire Training Systems count on Hypertherm to get the job done. Visit www.hypertherm.com or call 800-737-2978