DNC system allows aerospace manufacturer to produce parts without massive memory upgrade

Modern Machine Shop, July, 1991

DNC System Allows Aerospace Manufacturer To Produce Parts Without Massive Memory Upgrade

Justifying the purchase of a new distributed numerical control (DNC) software package was a pretty easy task for Andy Amstutz, production manager at Precise Machining and Manufacturing of Tulsa, Oklahoma.

The company runs eight CNC machine tools, and each one was going to run about $12,000 to install expanded memory. Each CNC machine has a memory requirement of under one megabyte but the code requirements could be as high as four megabytes per program.

Mr. Amstutz looked at several DNC packages before deciding on the Factory Automation and Communications Technology (FACT), manufactured by DP Technology Corp., 1150 Avenida Acaso, Camarillo, CA 93010. DP Technology is also the manufacturer of ESPRIT, which Precise Machining and Manufacturing has also been using for four years.

FACT is a DNC/factory automation network running under the Unix System V multi-user, multitasking operating system and X-Window 11 multiple windowing environment. At Precise Machining, the CPU is an IBM-compatible, 386-based, Hewlett-Packard Vectra running at 20 MHz, with eight megabytes of RAM and a 150-megabyte hard disk drive. FACT also runs on any IBM-compatible 386- or 486-based computers, as well as engineering workstations, such as the Sun SPARCstation and HP/Apollo 300 and 400 Series.

FACT allowed Precise Machining, whose frequent customers include Boeing, Hughes Aircraft, McDonnell Douglas, General Dynamics, and Rockwell International, to create parts that the company simply couldn't do before. According to Mr. Amstutz there are certain parts created by three-axis machining, such as frames for aircraft, that involve the use of "mold line data." These programs can run into the millions of characters of code. Without a "true" DNC system or massive memory upgrades, the company could never manipulate that much data at once.

One particular feature used at Precise is rotation and the mass substitution of X and Y coordinates--a feature available on both FACT and ESPRIT. It allows complete transposition of the length and width of a part, plus the changing of a few other parameters, then running the part.

There were efficiency gains in other areas as well, including operators not having to load paper tapes, the elimination of problems caused by lost or worn tapes, accelerated input and output, and improved organization of jobs, through the storage of all part and tool data on a central hard drive.

The system can also edit files of unlimited length with nearly instantaneous response. Under Precise's previous setup, it would take 30-60 minutes to load each program into the NC editor. Now, a part program can be loaded in minutes. Code may also be combined from two tapes, or data copied from one to another.

Under FACT, the operator is free to edit NC code or manage information on the file server during the entire process, as all data transfer takes place in the background.

The purchase of the entire DNC package eliminated the need for added memory and was one-third of the cost.

Between productivity gains and increasing the ability to manufacture new parts by almost forty percent, the system paid for itself in less than three months.

PHOTO : Utilizing the FACT DNC system (shown here running under ESPRIT) from a central location saved Precise Machining and Manufacturing from expensive memory upgrades for each of their eight CNC machines.