Assembly Planbook - July 2008 - (Page GM-19)

several hundred automated guided vehicles for use in engine dress, trim and chassis lines. Here’s a look at four trendsetting GM facilities that have opened in the United States since Richard Nixon was president. line operations for greater efﬁciency and accuracy. A computerized system was used to balance workloads along the assembly lines that built the innovative Vega sedan. “The system allows individual operators enough time to do a job correctly, which minimizes line disruptions To meet cost objectives, four different models of the Vega 2300—a hatchback, a wagon, a two-door sedan and a panel van—were built on a single, ﬁnal assembly line. All four bodies shared the same hood, bolt-on fenders, engine compartment and front-end panels to mini- Lordstown General Motors spent more than $75 million retooling its Lordstown, OH, plant in the late 1960s to produce the new Chevrolet Vega. The subcompact sedan was aimed at imports, which were slowly trickling into the United States. When it opened in 1970, Lordstown was touted as the most automated automotive plant in the world. Thanks to computer-controlled automation, it boasted the fastest assembly lines in the auto industry. The new factory could assemble more than 100 vehicles per hour vs. 55 to 60 cars at other auto plants. More than 90 percent of body welding operations were automated vs. 20 percent to 40 percent at traditional auto plants. The state-of-the-art Lordstown plant featured 75 automatic welding devices, including 26 ﬁve-axis Unimate robots that each performed about 20 spot welds. “Each can move a welding tool through a predetermined series of motions to provide weld accuracy within 1/16 inch,” reported a feature article in the October 1970 issue of ASSEMBLY. “Each Unimate memorizes the exact ‘point-in-space’ location for each weld position. On command, it accurately repeats the pattern of tool movements and produces 2,000 welds per hour.” Engineers also harnessed information technology to simplify assembly and out-of-station repairs,” reported ASSEMBLY. “When options or model mixes change, the computer can immediately rebalance the line for the new conditions.” Simulation was used extensively to optimize assembly operations. Critical systems and major subassemblies were assembled thousands of times in a computer through the use of mathematical models. Dimensional tolerances, ﬁxturing and assembly sequence were predicted for a large number of units before a single vehicle was actually built at Lordstown. GM has opened more than 20 new assembly plants around the world. Manufacturing engineers focused on two main objectives: make the task of the assembly line employee easier and simplify the approach to quality control. The Vega used 43 percent fewer body parts than the Chevy Impala. For instance, the Vega used only 1,231 individual pieces vs. 3,500 for the Impala. mize both parts and variables in assembly operations. “Fewer parts mean fewer assembly operations, less chance for assembly errors and a potentially higher online quality level, all without sacriﬁcing body strength and passenger safety,” explained ASSEMBLY. “Fewer parts require fewer joints, fewer seals and reduce the possibility of water leaks.” While automation was hailed as a success at Lordstown, the plant quickly became a hotbed of labor unrest. Multiple work stoppages culminated in a bitter strike in the early 1970s. Today, Lordstown assemblers build the Chevy Cobalt and the Pontiac G5, and it is one of GM’s most productive plants. (Above) When it opened in 1970, Lordstown was touted as the most automated automotive plant in the world. (Left) The NUMMI plant ushered in a bold new era in the U.S. auto industry. NUMMI In 1983, GM and Toyota Motor Corp. (Nagoya, Japan) created a joint-venture called New United Motor Manufacturing Inc. (NUMMI). The new www.assemblymag.com | July 2008/ASSEMBLY | GM - 19 http://www.assemblymag.com

Table of Contents Feed for the Digital Edition of Assembly Planbook - July 2008

Assembly Planbook - July 2008 Contents Editorial Quality in Assembly Station to Station Assembly Lines Assembly in Action Surviving the Roller Coaster The Human Side of Manufacturing Do Your Fasteners Need a Preapplied Thread-Locker? Manufacturing Innovation A Century of Progress Trendsetting Plants Pulse Tools Get Smart Plastics: Design for X Product Reviews Products Advertisers Index Classified Leading Lean

Assembly Planbook - July 2008

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.