5-Axis Programming Made Simple(r)

Manufacturing Engineering, Mar 2005

Aerospace Dynamics International Inc. (ADI; Valencia, CA) is a $60 million prime contractor supporting aeronautics and aerospace OEMs. The company manufactures large components such as aircraft wing spars, bulkheads, and panels.

Due to their large size and critical applications, these parts can be difficult to machine. "Our parts are very large, and we must hold extremely close tolerances," explains NC programmer Brian Carlson. "Yet our customers are raising the bar higher and higher in terms of how soon they expect delivery."

In the past, ADI programmers used either an Automatically Programmed Tool (APT)-like NC programming language to code toolpath motion by hand, or an earlier-generation graphical CAM program. There were drawbacks to both methods.

Hand coding could achieve very precise toolpath motion even on high-speed, five-axis machines, but it was time-consuming. And, it was difficult for programmers to work on each other's projects. "They had to be dragged kicking and screaming to another's job," Carlson recalls. "Coding style differences had become a big problem."

The other method, using graphical CAM software, sped program creation somewhat but was still labor-intensive when used to create toolpaths for high-speed machines. It was also difficult to revise programs once they were generated.

Installation of seven seats of NX Machining CAM software from UGS (Piano, TX) gave ADI the combination of fast programming and complete motion control needed to meet tight delivery schedules. For jobs that require high-speed, fiveaxis machining, the software has become ADFs programming method of choice.

"The sequential mill function in NX Machining allows us to program any feed rate change, any stepover, looping passes, whatever we need," Carlson says. "NX Machining also makes it easy to modify existing programs. If a machining technique programmed in other CAM systems doesn't work, it can be a real bear to modify the code."

The ability to create complex toolpaths accurately saves ADI a great deal of time. An example is programming for ribs of a commercial airplane. Originally done with the APT-like language, the initial program took 400 hr to write. Subsequent programs in a series required about 260 hr of work.

When the company won a contract for similar ribs, Carlson decided to do programming in NX Machining. "The first program took 260 hr, the second took 190, and the third took 152," he says. "On the first program with NX Machining, we equaled the best we could do with all our experience in hand programming. On the last, we took more than 100 hours off the best time we had ever accomplished by hand."

Other programs for space shuttle fuel panels used to take 10 days per panel with hand coding. With NX Machining, one panel (the last in a series of six) was recently programmed in three days. "That was very fast, but all six were perfect to plan," Carlson says. "The motion was every bit as good as hand-written code." * Circle 311