INDIANAPOLIS - Standing beside a computer-controlled machine nearly two stories high, auto worker Ron Fuller glances at the computer display before him, then taps the pressure-sensitive screen with a forefinger.
Above his head the machine is deftly twirling an engine block that weighs hundreds of pounds. Methodically, almost silently, the machine uses its mechanical arm to grasp metal pistons from a nearby line and insert them into the engine.
The machine performs the sequence of tasks tirelessly, without any commands from a human. Fuller’s job is to monitor the performance of the five ‘‘pistonstuffing’’ machines that have been operating at Navistar International Corp.’s sprawling diesel-engine plant here since early 2002.
Two years ago, he said, the work now handled by the machines ‘‘took 10 people on every shift.’’
That’s just the work cuts in Fuller’s modest corner of Navistar’s 1.1 million-squarefoot Indianapolis plant. Altogether, the Warrenville, Ill.-based truck and engine maker eliminated about 400 jobs — or a quarter of the plant’s workforce — through a $350 million automation program that has trimmed employment at the site to about 1,200.
The same kind of productivity enhancing, jobshrinking makeover that occurred at Navistar’s once grimy engine plant is playing out in factories across America. In automating their plants as part of a stepped-up search for efficiency, American companies are vaporizing tens of thousands of jobs every year.
‘‘The automation of factory production is just as significant as globalization for explaining the loss of manufacturing jobs,’’ says Robert Reich, a professor at Brandeis University and former labor secretary in the Clinton administration.
Indeed, although it is a wrenching process, many experts argue that sacrificing some jobs to automation may be the best way to prevent millions more U.S. jobs from migrating offshore.
Since mid-2000, a total of about 3 million U.S. manufacturing jobs have vanished. The disappearance of almost 18 percent of the nation’s production jobs has hurt the families of displaced workers, put a drag on the U.S. economy’s recovery and, with elections coming, has become a charged political issue.
Many of those jobs were lost to the recession that took hold in 2001. But a good number of them are not coming back, even when the now recovering U.S. economy regains its former vigor.
Many people blame the downbeat jobs outlook on U.S. manufacturers who are shifting production to cheaplabor nations such as China or Mexico. In addition, many smaller U.S. companies have simply tossed in the towel and gone out of business in the face of offshore competition, throwing their employees out of work.
But as candidates rail against foreign competition, they are ignoring a less visible factor that is also claiming American jobs: Automation.
American manufacturers have been automating plants — replacing workers with ‘‘smart’’ equipment like industrial robots and computerized factory machines — since the early 1980s.
But the automation trend has been accelerating in recent years, as U.S. companies face intense price competition from abroad at the same time that soaring health-care and pension costs have been making U.S. workers ever more expensive.
U.S. automakers have eliminated thousands of jobs, as have the companies that supply them with components.
Automation can have an impact on the nation’s job scene even when no workers lose their jobs. Over the past several years, Chicago building-products maker USG Corp. replaced five drywall factories with all-new facilities, allowing it to double output at those sites without hiring any new workers.
The automation trend may be one reason that U.S. employment has been recovering at such a disappointingly slow pace.
The new surge in automation is being fueled in part by technical advances, said David Autor, a labor economist and Massachusetts Institute of Technology professor.
The price of industrial robots and other manufacturing technology has declined dramatically, he said, and so ‘‘there’s been an enormous change in the amount of the bang companies are getting for their buck.’’
The lower cost alters an employer’s calculation as to whether it makes economic sense to replace human labor with capital equipment. In addition, says the economist, manufacturing gear has become more flexible and adaptable.
It is not wrong for U.S. manufacturers to seek such efficiencies, many observers suggest. By eliminating 300 jobs through automation, they argue, an American factory might save 900 other jobs by rendering the plant efficient enough to withstand foreign competition.
In such circumstances U.S. companies ‘‘face two choices,’’ said Autor: ‘‘One is to outsource (offshore), the other is to automate.’’