To celebrate the 20th anniversary of
To celebrate the 20th anniversary ofPlastics News in 2009, we continue with our weekly countdown of the Top 20 issues of lasting impact. The series will end with the No. 1 issue in our 20th Anniversary special edition March 16.
No. 12: Machinery innovations for energy savings
These days “green” is the buzzword for plastics machinery. To a casual observer, this all just got started. Injection molding press makers touted the energy efficiency of their equipment at the Fakuma show in Germany in October. Also, it's clear that green machines will be a major trend at NPE2009.
Right now, it seems like all the talk of “green machines” is part of the sustainability/Earth-friendly movement sweeping society. Every part of the equipment supply chain — from dryers to primary machines to screws and barrels — is dutifully compiling information on how much energy their products save.
But think about it: Constant efficiency improvement is a basic principle of manufacturing. For decades, plastics machinery has been on a steady march forward to put out more products, faster, using less energy.
Much of the energy-saving focus has centered on all-electric injection presses, which consume much less energy, even 60-80 percent less, than an old-style hydraulic press. But make that all-electric energy claim, and you'll still get an argument from some machinery executives. And part of the reason goes back to the history of injection presses and other types of processing machinery. Equipment and machine controls have steadily improved over time — since well before Plastics News started publishing in 1989.
Hydraulic power dates to the earliest days of injection molding, when workers pumped machines by hand to build up oil pressure. Motors increased the output. Accumulators were added to speed up the injection. The reciprocating screw largely replaced the plunger, both mixing the plastic and pushing the melt into the mold.
The science of hydraulics improved dramatically over the years, as machinery makers adopted new technology such as servo valves, variable-speed motors and improved varieties of displacement pumps. Today, some hydraulic motors can shut off completely when no machine motion is happening, to provide big energy savings.
But the all-electrics have really taken off in the U.S. market. After several years of steady market-share growth, all-electrics today account for more than half of all presses sold in the United States.
Cincinnati Milacron Inc. (now called simply Milacron Inc.) did much of the early spade work. In 1990, Milacron introduced its first all-electric — actually a press made in Japan by Fanuc Ltd. Milacron introduced its own U.S.-made all-electric at the 1994 NPE show in Chicago.
Other Japanese injection press makers followed, by selling their all-electrics — long popular in Japan — into the U.S. market. Europeans came to the table as well, although all-electric presses are far more popular in Japan and the United States than in Europe.
Machine controllers have evolved dramatically since Plastics News' early days. Controllers are much more powerful and easier to use. Today, plenty of plastics processors, large and small, connect their shop-floor machine data to plantwide monitoring systems. So equipped, management can extract every last bit of efficiency out of an operation.
So efficiency is not all about energy. You can figure out everything from machine scheduling to maintenance, down to running leaner inventories.
Bregar is an Akron, Ohio-based
Bregar is an Akron, Ohio-basedPlastics News senior reporter.