- August 01, 1996, Mykytiuk, Andrew
In 1962, when Herbert Baier, president of Peco, Fairfield, NJ, entered the converting business, the state-of-the-art blown film line was making extruded film at 30 fpm, and that was considered unbelievably fast. Obviously the business has changed much, but one thing hasn't changed: the continuous demand for ever-increasing line speeds. "Today, extruders are producing film at 300 to 350 feet per minute," says Baier, "and everybody wants bagmaking machines to stay in-line with the extruder and flawlessly make bags at that speed as well."
Baier explains that, except for refinements, bagmaking machines have changed very little over the past ten years. "The big evolution has been in electronics," he says. "You can do so much these days with programmable logic controllers, whereas in the past you had a million and one fussy little 'click-clack' relays."
Tom Helming, converted products sales manager for Battenfeld Gloucester, Gloucester, MA, wrote a paper for the Society of Mechanical Engineers in which he stated that virtually all up-to-date bagmaking machinery manufactured today incorporates AC servo motors and controllers. Their job is to turn the draw rolls to accurately index the correct amount of film to make a perfect bag every time. The advantages of servo drives include extremely accurate stop and start, the ability to accurately repeat a move, and the ability to stop and hold a position while hot knives perform sealing and cutting operations. The newer servos have encoders engineered to send a signal to an amplifier, which then precisely translates the number of motor rotations, or fraction of a rotation, into a linear distance, or simply put, bag length. The encoder disseminates this information to every part of the machine for the perfect timing/coordination of all other machine functions.
In addition to servo controls, notes Helming, bagmaking machines are taking advantage of today's more powerful computers to control the servo drives and provide timed outputs for other devices on the machine. Helming says that in the past CPU restraints limited machine output, because they were not able to keep up with the constantly increasing cycling speeds. Today's computers are fast enough to calculate an optimum 'move' (acceleration/deceleration curve) for each bag being made, based on the bag length, machine speed, and programming variables. And finally, Helming reports that operator interfaces have evolved to the point where they actually guide an operator through various levels of commands to access any parameter needed to run the machine.
"Bagmaking machines tend to be finicky," says Helming. "There are a lot of moving mechanical parts, and there is a kind of 'magic' in making them run right. The level of control in servo controllers today is making these machines far more automated, easier to set up, faster, and more consistent, in effect taking the magic out of running them."
Pouches are the Hot Ticket
Today's hot bagmaking markets, according to Gary Gould, president of GN Packaging Equipment, Mississauga, Ont., Canada, are zippered pouches, stand-up pouches, and pouches that hold liquids. "The biggest growth during the past two to three years has definitely been in the liquid pouch area of our business," says Gould. "And I see that growth continuing."
He explains that, as new, high-performance substrates continue to be introduced, packaging designers are given a wide design latitude to create new packaging that no one would have imagined just a few years ago. Once the new packaging is introduced, it doesn't take long for the consumer to sample the product, and, if it truly is an improvement, the demand for it skyrockets, sometimes seemingly overnight.
"Three years ago liquid pouches were a very small part of our business, but for some reason, in the past several years they have become a major part," says Gould.
Today's bagmaking machinery manufacturers keep close tabs on new materials and consumer preferences, quickly bringing machines to market that incorporate the latest technology.