After a decade of mergers between aerospace companies such as Boeing and McDonnell-Douglas, Lockheed-Martin, and Northrup-Grumman, the industry has gone through some rather significant changes. Among these are downsizing of their workforce and the trend to sub-contract much of their manufacturing work, especially to machine shops with five-axis machine tools. At the same time, these companies have trimmed their supplier list to include only their most dependable suppliers. With the recent surge in commercial aircraft orders and the continuation of major defense programs, the demand on these suppliers has never been greater. In some cases, lot sizes have become smaller, requiring suppliers to be more flexible. In other cases, assemblies are being replaced by a single part, increasing the need for more complex machining. And of course, the aerospace companies want lower prices and higher quality. However, a very positive note is that they are still offering multi-year contracts.
Within the group of suppliers who manufacture complex structural parts is High Tech West, Inc., (HTW) located in Long Beach, California. The company was started in 1984 by Dal and Tom Rogers as a five-axis airframe machining house, specializing in the capability to machine complex contoured parts. The growth that aerospace suppliers are experiencing is reflected by HTW's recent move into a new facility that quadrupled the size of their former quarters. In order to meet the ever increasing demands of the industry, everything is state-of-the-art, including inspection devices, CNC software, and of course machine tools.
A recent machine addition is a case in point. The company acquired a Viper-2100, one of five models in a series offered by Mighty, USA, Inc. According to Tom Rogers, the new machine fills a niche that the other manufacturers didn't offer—a heavy-duty VMC with an 81 inch by 42 inch table. The machine is being used to machine aluminum and titanium, especially on "hogging" operations on large slabs of aluminum. Mr. Rogers stated,"The Viper is really solid with its heavy-duty Meehanite casting. We're using a two-inch diamter, two-flute, M4 end mill to machine over 1,000 lbs off a 1300-lb, five inch slab and there's no evidence of vibration or chatter. The depth of cut is 0.5-inch at 3200 rpm, and the feed rate is 60 ipm. The part finish clearly shows how solid the machine is."
In addition to the solid frame, the Viper uses large ballscrew assemblies for maximum rigidity and precision. The ballscrews are located in the exact center of each axis, which effectively eliminates heat and lost motion. High torque AC servo-units are directly coupled to the ballscrews, moving the axes faster and with more precision. Equipped with "state-of-art Mitsubishi AC digital motors, cutting is minimized with the high reliability, speed and precision feed movement.
Most projects arrived on IGES files and NC programs developed with MATRA Sabre multi-axis system with postprocessor. ProComm is used to transfer NC programs. And software for quality assurance is Geopack and Scan Pack.
Of course, the purpose of state of the art machines like the Viper, and various software programs is to improve "cut time," or rather, the time a machine is actually cutting parts. The more productive a machine tool, the more profitable the business. With the demands in the aerospace business ever tightening, machine efficiency is the key to a successful business.