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INSIGHT IN 1954, RESEARCHERS at the Massachusetts Institute of Technology were still studying the radical idea of numerical control (NC) of machine tools. Although commercial application of these machines was still years away, AM editors described their great potential in an article on what NC would mean to metalworking. Discounting the idea that NC could lead to the four-day work week or the six-hour day, their predictions were pretty much on the mark. "Operators will be retrained as observers or as maintenance men. Machinists will be taught setup or programming. Tool Engineers... will learn a new approach to tooling. Instead of designing massive fixtures or intricate mechanical controls, they will `program,' and much of the tooling will be accomplished on mathematical charts. Of course, fixturing and special tooling, plus cutting-tool design and selection, will be required, but the problems will be different. Because the human variables are absent, time study will change its scope. Production time will be a function of machine-tool and work limitations - easily determined and maintained." The article provided a list of NC's advantages, including automatic performance of machining operations, rapid interchangeability of control instructions by inserting a new set of previously prepared instructions, smaller number of work setups, reduced machining time, greater machine accuracy, and increased machine tool utilization. WHERE'S THE REMOTE? TODAY'S SHOPS HAVE THE OPTION of running machine tools from an office away from the shop floor via an intranet system. Or they can operate and monitor them from an off-site location through the Internet. Either way, the goal is to eliminate the need for the operator to babysit the machine. This was also the goal of one machine shop back in 1969. In an AM article, a plant maintenance electrician came up with a way to give machine operators emergency control over an NC machine from anywhere within a 40-ft radius. He used a radio-controlled garage-door system to operate the main power-line contactor at the machine's controls. This garage-door opener system consisted of a VHF receiver installed at the control cabinet and a matching transmitter carried by the operator. The battery-powered transmitter measured 3X4X1 in., so operators carried it in their apron pockets. No, neighboring garage doors did not open every time the operator pushed the pocket-transmitter button. The reason was because the shop was located deep inside a large industrial plant at least half a mile from the nearest highway, and transmitters of that type were tuned to respond to individual frequencies. So the possibility of accidentally triggering the machine by a driver toying with another transmitter of close frequency was, as the article stated, "almost impossible." Running a machine with a garage-door opener may have been state of the art in 1969, but beeps and whistles were the hot operating system in 1956. On the cover of AM was a spar and skin miller dubbed a "musical skin miller" because it ran on beeps and whistles. Magnetic tape in the control system carried 14 channels on which were recorded signals of various frequencies. A 2,000-cycle tone on one channel started coolant flowing, and other notes on other channels started and stopped drives, moved chip conveyors, and activated other such operations. LEARNING COMPUTERS IN 1951, AM EDITORS REPORTED on a "robot's robot," a new simpler electronic calculator called Simple Simon. Unlike AT&T's super- robot that could memorize and compute 350 million numbers, Simple Simon was designed to remember 16 numbers and run a little slower than the giant, more expensive machines. TAPE MEASURE WHILE MOST OF TODAY'S shop programmers worry about having enough memory in their computers, those back in 1969 were concerned with exactly how long their NC tapes were. This wasn't just for fun, mind you, but to determine punching time on remote-terminal setups. Based on a survey, the average tape length was 117-ft long. However, this average was comprised of many short tapes and relatively few long ones. But one company in the automotive industry reported a body-die tape measuring 3,000-ft long. WHEN CNC WAS A FLOP TWENTY YEARS AGO, the cutting edge in computer numerical control (CNC) was the 51/4-in. double-sided floppy disk (run on 256-K computers, no less). These disks, which people were cautioned not to fold or crease, held about 1 million bytes of data - equivalent to 8,000 ft of punched tape (20 reels). This was quite a step up, considering that, at the time, an average NC program's tape ran about 400 ft. AM editors were quite agog at this "vast" amount of data, raving how it only took five to ten minutes to fully load a floppy disk. Shops did, however, have the option to download program segments directly to a machine tool. But the data-transmission rate was limited to 1,200 bytes per second, and many complex parts could take a half-hour or longer to transmit to a machine.
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Source: American Machinist / Copyright Penton Media, Inc. Jun 2002
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