SAMPE 2011 Long Beach Product Showcase

The annual Society for the Advancement of Material and Process Engineering’s (SAMPE) Convention & Exhibition returned, for the first time since 2008, to its long-time base in Long Beach, Calif., after a first-ever Pacific Northwest showing last year in Seattle, Wash. The four-day event, held May 23-26 at the Long Beach Convention Center, met with considerable success. The SAMPE 2011 exhibit hall was sold out this year, with 356 exhibitors (including 106 first-time exhibitors) representing 555 companies. Attendance figures indicated the show took a large leap; the official count topped 7,100, with delegates coming from 48 U.S. states, the District of Columbia and 27 other countries.

Organized by SAMPE’s Orange County Chapter, the SAMPE conference was cochaired by Joyce Lentz, president of National Aerospace Supply Co. (San Juan Capistrano, Calif.), and Darrell Reed, quality control engineer at OCM Test Labs (Anaheim, Calif.). Eight tutorials and more than 250 technical papers were presented by M&P practitioners and researchers.

"SAMPE is on an upward trend," commented Dr. Allan Crasto, associate director at UDRI (Dayton, Ohio) and sitting SAMPE international president. "We seem to have fully recovered from the impact of the recession.” On Tuesday, conference delegates attended a keynote presentation on “Understanding and Managing Risk in Human Space Flight Developments and Operations” by Dr. Mike Ryschkewitsch, chief engineer at NASA. He discussed NASA’s approach to certification of systems for human spaceflight.

Wednesday’s keynoter, Andreas Wüllner, managing director of SGL Automotive Carbon Fibers GmbH (Munich, Germany), filled in the background on the events that led to the much-publicized decision by the SGL/BMW joint venture to build its now nearly complete captive carbon fiber production plant in Moses Lake, Wash. Wüllner reported that the carbon fiber manufacturing facility is complete and that testing of the first production line will begin this summer, followed by the plant’s official opening sometime in third quarter 2011. In his presentation, “SGL Carbon Group – BMW: A Visionary Joint Venture for Carbon Fiber Composites in Automotive Applications,” he updated the audience on the development of the BMW all-electric i3 and hybrid electric i8 vehicles, both of which make use of resin transfer molded SGL carbon fiber composites in the passenger cell, called the Life Module. During the Q&A after his address, Wüllner was asked about repair of carbon fiber composites on the two car models in the event of damage. Wüllner said that BMW is establishing dedicated global repair facilities designed specifically to repair damaged composite structures. He would not say, however, whether body panels (hood, roof, door panels, etc.) on the i3 and i8 would be made of composites.

How to Build a Plasma Cutter

4. Gas supply

The gas supply is the easiest part because there are lots of choices available. If you already have an air compressor then you just need to make sure it supplies enough volume. Plasma cutters use between 4 to 8cfm depending on the current output. The higher power plasma arcs require more CFM. Usually the pressure is between 65 to 90 psi. Don't forget that the air supply needs to be clean, oil free, and dry.

The torch will come from an existing plasma cutter. Making a torch isn't practical. It would be extremely time consuming to make all the parts and the electrode is made of a not so common metal. The type of electrode metal depends on the gas used. Air and nitrogen use the same metal. And one last but not least point about the torch is that the nozzle and electrode are consumable so a ready supply of replacement parts is required.

The starting circuit. This is doable. The starting circuit usually consists of a high frequency source, an oscillator that causes an arc inside the torch nozzle. When the compressed air flows through the arc it is heated to a high temperature and becomes ionized. At this point the gas becomes plasma and will conduct electricity. The arc is transferred from inside the nozzle to the work piece and the high frequency circuit turns off. Another type of starting circuit doesn't use high frequency and shorts inside the torch to start the arc. I think that would be a function of the torch itself.

The power supply is a major component of the plasma cutter. It provides current between about 10 amps up to about 100 amps depending on what size monster plasma cutter you want to build. The more current the more it will cost. The output voltage is somewhere between 100 volts dc to about 300 volts dc. A good power supply will be regulated and filtered to provide a good clean output. Cost to build a power supply depends on what parts you use. New parts, used parts, make your own parts. Cost will probably run around $300 more or less depending on what the current requirements are. More current equals more money.

My opinion about building a plasma cutter. Although it is doable and many ingenious craftsmen and workshop inventors have built plasma cutters I make the following suggestions;

1. Buy a new plasma cutter. The new models have vast improvements in starting circuits, electrode and nozzle design, and consumable life over older models.

2. Buy a used plasma cutter. Even the older units will more than likely be better designed and more efficient than a homebuilt plasma cutter.

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