Plasma Cutter Industry | CNC

Plasma cutter lets fabricator's business grow

Kirk & Blum (Lexington, KY), an industrial sheetmetal enclosure and process-piping system fabricator, had always relied on shearing equipment, saws, presses, grinders, notchers, punchers, and welders foi many types of custom sheetmetal and steel plate fabrication projects. Recently it found that its mechanical tools could not handle the complex designs, precise specifications, and just-in-time delivery schedules custom orders required.

It began declining manufacturing contracts or transferring work to other K&B locations to meet product specifications and schedules. It was also reluctant to pursue new custom-parts manufacturing contracts aggressively. "New clients needed their orders filled on demand," explains R.J. Blum, K&B's president. "Before we could bid on these contracts, we needed to increase our accuracy and speed up deliveries to within 24 hours."

Drawing on the shop's previous experience with plasma cutters and the advice of Kentucky Utilities Company (KU), the company's power supplier, and the Electric Power Research Institute's Center for Materials Fabrication, K&B decided to install a computerized plasma cutter at its Lexington facili ty. The cutter made fabrication on demand possible for KAB.

K&B's high-definition plasma cutting systems have an 8 X 20' (2.4 X 6 m) cutting area. A single moving head supports two torches that can cut through 2" (51 mm) of material with accuracy within +/-0.01" (0.25 mm) on most materials 3/8" (9.5 mm) or thinner. For materials 1" (25 mm) or thicker, an air drill with scribing and etching capabilities pierces a starting point. The cutting table has special exhaust dampers, allowing all air used in the plasma cutting process to be captured, cleaned, and recycled.

K&B's 200 amp plasma equipment draws 20-30 kW and averages 480 kW per day, for an average cost of $19 per day. The company runs the cutting operation two shifts a day, occasionally operating three shifts to meet increased demand. Ongoing maintenance costs are primarily nozzle and electrode replacement, at a cost of $8 tc $15. Each replacement is good for 700-1000 ignitions.

Today, says Bill Wells, K&B vice president and manager of the Lexington facility, "When customers provide us with schematic diagrams and engineering specifications, we load them into the computer and cut the parts. Using the computer to work directly from customer specification sheets or drawings also helped cut our delivery time from roughly three days to under 24 hours."

Computerized plasma cutting simplifies business, says Wells, because the cutters tackle unique geometries with ease and store specifications on disk. With computer memory, it's fabrication on demand. Parts need not be warehoused for repeat orders. The $250,000 investment in the plasma cutter has improved overall cost effectiveness. "Computerized cutting lets us nest parts more closely, which boosts the number of parts we get per sheet," says Wells.

Since KAB manufactures control panels for Kentucky Utilities, KU has been able to observe the results "Using the plasma cutters, K&B has been able to deliver control panels in a fraction of the time it took us to produce them ourselves," said Phil Roberts of KU. As for K&B, it's no longer in a no-growth mode. Blum is now aggressively pursuing new business because he knows the company can meet any product specifications and delivery schedules a new customer throws at him.

Copyright Society of Manufacturing Engineers Sep 1997
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