The Kearfott Guidance and Navigation Corporation (Wayne, New Jersey) facility in Black Mountain, North Carolina, currently uses a combination of CNC mills, grinders and lathes (a total of 27 machine tools) to cut and shape a variety of metals, mostly aluminum and stainless steel, in order to build its systems. Until recently, punched paper tape was still being used to transfer part programs into the machine tool controls. However, the company's manufacturing processes have undergone a metamorphosis that has saved the company time as well as money.
According to John Sidelinker, Kearfott's Senior Manufacturing Engineering Programmer, the company generally had no problems with the paper tape system and the company's upper management saw no reason to change the manufacturing methods since all the equipment seemed to work properly. Mr. Sidelinker, though, had been talking to senior management about the advantages of using a DNC system for years.
While the number of companies using the punched tape method of parts program transfer became fewer and fewer, the price of the formerly inexpensive tape and the equipment increased; some parts were not even available. By 1995, Mr. Sidelinker used this information to convince Kearfott's senior management to get bids on a new networking system.
The company sought out bids on DNC software applications and industrial PCs. After receiving its bid, Mr. Sidelinker contacted Greco Systems (El Cajon, California) for more information, and for more than two years, he kept in touch with the staff at Greco Systems and the other companies submitting bids until Kearfott's senior management said he could pursue the purchase of the DNC networking system in the fall of 1997. Mr. Sidelinker chose to purchase Greco Systems' network.
The purchase order was cut in September of 1997 for one WinDNC software package, two Touch Station industrial touch screen PCs with 16-port rocket boards, three Machine Tool Interface Controllers (MTICs) and two WinNC Edit software applications. WinDNC is a Windows-based DNC application that provides an automated method of storing and transferring NC part programs to machine tool controls via a local area network (LAN) or Ethernet for simultaneous communications to multiple users.
The MTICs work as standard interface devices and provide the serial to parallel conversation for older controls equipped with tape reader or punch units. This unit provides full reader and punch emulation for bi-directional communication with the CNC control to a PC or other parts program memory storage device.
The hardware is built to withstand the environment of the shop floor. The decision to buy the Touch Stations over standard PCs was due to their ease of use. Kearfott originally chose to have Windows NT loaded by Greco Systems, but later decided to have Windows 95 loaded instead. WinDNC and WinNC Edit were also loaded before shipment.
Within weeks, the company received the equipment. Over a period of time, a Greco Systems' technician installed the equipment and got the company's machine tools to communicate within a networking environment. Currently, there are 27 machine tools running on the DNC networking system.
The system is configured so that the Touch Stations are set in two separate sections of the shop floor—one is set near the 10 mills and two grinders and one is in the section housing the 15 lathes. The part programs are stored in the file server, which is in the programming office, and linked to the Touch Stations. Each day, the shop foreman assigns and prints a job schedule and tool list for each machinist.
If the program requires that the machinist edit the program, it is possible to do so at the control (with supervision) and upload the edited program into a separate file on the server. Once this is done, Mr. Sidelinker uses WinNC Editor to do a side-by-side file comparison of the original program and the edited version to decide whether to keep only one of the programs or both.
Machinists had hands-on training sessions with the technician. Most of the operators had the system mastered within 30 minutes, Mr. Sidelinker said.
The new system saves the company money due to the elimination of setting up the tapes and the creation of "tape packages" which consisted of a tape, setup (tool) instructions and the program information.
The shop has changed a lot. Today, while Mr. Sidelinker still creates a manual tool sheet and the shop foreman creates a paper job schedule, the shop is nearly paper-free. But all the paper instructions will go away soon, if Mr. Sidelinker has his way. "That's my next goal—it's to computerize that part of the operation," he said. "It's the only manual part that's slowing me down."