International Business Machines Corp.
Controlled by instructions generated by IBM’s AUTOPROMPT, a Pratt & Whitney Numeric-Keller continuous-path milling machine shapes a raw aluminum block (upper left) into the saddle-shaped piece shown at right. The surface is a portion of a geometric shape called a hyperbolic paraboloid.
A coded tape, generated by a computer, controls the milling machine, drill press, or shaper more accurately than the human machinist could. In effect, the computer studies a blueprint and punches out instructions on tape that tell the machine what it is to do, how much of it, and for how long. Huge shaping and contouring machines munch chunks of metal from blanks to form them into complex three-dimensional shapes. Remington Rand UNIVAC and IBM are among the companies producing computers for this purpose. The trend is to simpler, more flexible control so that even small shops can avail themselves of the new technique. In a typical example of the savings possible with “numerical” tape control, these were the comparative costs:
Control Engineering
Operation of computer-controlled freight yard in England.
| Conventional | Tape Control | |
| Tooling | $755 | $45 |
| Setup time | 15 min. | 15 min. |
| Work time | 15 min. | 11 min. |
| Cost per part | $2.96 | $1.81 |
Beyond the automated single- or multipurpose tool is the completely computer-controlled assembly line. Complete automation of products like automobiles may be some distance off, but there is nothing basically unworkable about the idea. Simpler things will be made first, and to promote thinking along these lines, Westinghouse set up an automatic assembly line for paperweights. An operator typed the initials of manufacturing department managers on a computer, which transferred the instructions to a milling machine. The machine cut the initials in aluminum blocks which were then automatically finished, painted, and packaged for shipment as completed paperweights.
Another firm, Daystrom, Inc., is designing a computer control system for assembly lines which will adjust itself for the “best” product as an output. President Tom Jones described the principle in which the computer will begin production, then move valves, switches, or other controls a small amount. Measuring the finished product, it will decide if the change is in the right direction, and proceed accordingly. Once it finds the optimum point, it will lock in this position and settle down to business.
An excellent example of the computerized assembly line is the Western Electric Company carbon resistor production line at its Winston-Salem plant. A digital computer with a 4,096-word memory is used for the programming, setup, and feedback control of the eleven-station line. It can accept a month’s scheduling requirements for deposited carbon high-quality resistors in four power ratings and almost any desired resistance values. Production rate is 1,200 units per hour.
The computer keeps track of the resistors as they are fabricated, rejecting those out of specification and adjusting the process controls as necessary. Operations include heating, deposition of carbon, contact sputtering, welding, grooving, and inspecting.