The Road to Gen3

Jan. 1, 2004
When General Mills set out a few years ago to find a better high-end, automated cartoning machine, the path led to a Generation 3 design that is producing dramatic gains in reliability and performance.

General Mills engineer Dave Lutz is a big proponent of what the packaging industry refers to as “Generation 3” automation equipment.

That’s not surprising, given that Lutz, a senior packaging engineering specialist at the Minneapolis company, has seen dramatic improvements in reliability and performance from his firm’s Gen3 cartoning equipment, when compared to earlier generation machines. In fact, says Lutz, since General Mills took delivery on its first Gen3 machine in early 2000, the company has now standardized on the technology for all of its high-end cartoning needs.

For General Mills Inc., the road to Gen3 began in 1996, when the consumer foods giant set out to find a radically improved cartoner for its automation packaging lines. “We were looking for a piece of equipment that would require almost zero maintenance, provide much higher uptime and give us a higher degree of reliability and performance,” observes Lutz, who is responsible for cartoner machine standards at the company’s North American plants.

That’s when the concept for a machine designed from the ground up to make maximum use of closed loop servo control technology—a hallmark of Gen3 equipment—began to take shape between General Mills and a few of its key machine suppliers. “When we started the program, we weren’t requiring servos,” Lutz says. “But when we approached a number of key cartoner vendors, a lot of them said that the only way they could meet our requirements was by using servos.”

At the time, the packaging industry was in the early stages of servo technology application. Some vendors were retrofitting traditional mechanical packaging machines with small numbers of servo motors and drives to handle a limited number of motion axes. The result was a class of hybrid machines that included both electrical and mechanical motion control elements—a design style that has come to be known today as a “Generation 2.” While these machines led to some improvements, they were often more expensive than their all-mechanical predecessors, and their advantages were often limited.

General Mills wanted more. The company had a long list of objectives for its new cartoner equipment, says Lutz. Among other things, General Mills engineers were looking for a machine with operational efficiencies rated at 99 percent that was capable of running three shifts per day, seven days per week, year around, he says. The machine had to be modular and highly flexible, enabling fast product changeovers with an ability to handle a wide range of carton sizes.

Minimal installation and start-up procedures—requiring 36 hours or less—were also extremely important, says Lutz. “We were going through a lot of changes, and every time we put a machine in, we were impacting the business by three or four days,” he notes. “So we wanted something that we could install, say, on a Saturday, and have running by Sunday night.”

Other requirements included simplified controls and attention to operator ergonomics. And as a way to reduce maintenance requirements, and cut down on part inventory needs, General Mills wanted a cartoner machine design that could be manufactured using 60 percent fewer parts than previous machines, says Lutz. A lower part count would also make the new machines faster for the vendor to assemble, meaning quicker deliveries. “We were looking for the first machine to ship within six months from the date we ordered it,” says Lutz, “and we wanted all future machines to ship within three months from date of order.”

As an added requirement, General Mills also wanted the price of the new machine to be substantially reduced, compared to the price of its current generation, high-end cartoner systems, Lutz says.

Too expensive

“A lot of the vendors that we talked to told us that they didn’t think there was a need for this type of machine, and that nobody would buy it, so it would be too expensive,” says Lutz. “That’s why our list of vendors was reduced to two or three very quickly, because back in 1996, a lot of people didn’t understand how to correctly use servo technology.”

According to Lutz, knowing how to use servo technology is as important in the packaging industry as the technology itself. To simply replace an AC motor with a servo motor on a mechanical machine, without eliminating the associated mechanical complexity, will do little beyond increasing the cost of the machine, he says. “A true Gen3 machine eliminates the mechanical transmission, eliminates the torque shoe and eliminates the auxiliary drive component,” he declares.

General Mills ultimately ended up working closely on the cartoner project with R.A. Jones & Co. Inc., a Cincinnati-based packaging solutions provider that had previously manufactured cartoners for the company.

“We worked and partnered very closely with General Mills on a clean-sheet design, embracing third-generation servo concepts,” confirms John Finck, R.A. Jones senior vice president. “It was a challenge for us make the leap from the current products we had to the new generation design, and to rethink the way we did things,” Finck allows. But the result of the effort was a new, Gen3 machine called the Criterion 2000 that not only largely met General Mills design requirements, but has also been “a very successful product” for Jones, says Finck.

General Mills took delivery on its first Criterion 2000 machine in early 2000 at its Minneapolis research lab, says Lutz. Instead of the all-mechanical or hybrid electrical/mechanical designs seen on earlier Gen1 and Gen2 cartoners, the new Gen3 machine relied on an electronic line shafting design incorporating Serial Realtime Communication System (SERCOS) fiber optic networking with nine servos and integrated motion control supplied by Rexroth Indramat, now known as Bosch Rexroth Corp., Hoffman Estates, Ill.

Expectations Exceeded

“The first cartoner we ran really exceeded our expectations,” says Lutz. “It was able to accept a much higher range of (carton size) tolerances than what our quality indexes were, so it had even greater flexibility than we required.” General Mills engineers tested the machine for about two months in the lab, then moved it to a production plant, where it was put through its paces in a real-world environment for about another 12 months before any additional machines were ordered, Lutz observes.

In one set of tests, engineers ran the new Gen3 cartoner in a side-by-side comparison against an older mechanical machine. The results showed dramatic gains for the Gen3 equipment, says Lutz, including a 10 percent improvement in packaging line performance, due to the new machine’s improved reliability and efficiency; a 75 percent reduction in product changeover times, going from “a couple of hours to just minutes;” a 60 percent average reduction in required maintenance; and a 40 percent improvement in recovery time when jams occurred.

“When a mechanical machine jams, there is a very loud bang. Unless you’ve got a very large brake on it, the machine coasts, because you’ve got a lot of inertia and mass that is moving at a very high speed,” Lutz observes. A servo-based machine can be stopped much more quickly, he says, because the electronic control system can drive the machine to a stop.

“With the mechanical machine, if it doesn’t stop in time, a lot of things can get out of adjustment very easily, because everything is slave driven on something else,” says Lutz. This means that an operator or maintenance person will typically need a set of wrenches and a screwdriver to reset the machine to zero. On a servo-based machine, by contrast, “when I hit the reset button, each motion is independent of the other, and they all go back to their last state and you’re ready to go again,” says Lutz. “There’s nothing to go out of time, because it’s an electronic shaft.”

Dial it in

Electronic line shafting also supports significantly faster machine installation and startup, as well as much quicker product changeovers. “We actually had one person, who had never seen the new cartoner, but was able to change it over in less than 20 minutes, without the need for any tools” Lutz says. The bulk of the work involved “dialing everything in from the HMI (human machine interface),” he says, “without having to go out to the machine and loosen something up, move it and tighten it back up again, which is what you have to do with a mechanical machine.”

Another Gen3 advantage is improved diagnostics and predictive maintenance capabilities, says Lutz. “With a mechanical machine, the only way we knew for sure that we had a problem and that something was going to fail, was to go out there with a lot of tools and check it out,” he notes. But the control system on the company’s Gen3 equipment enables real-time tracking of machine data, such as changes in servo torque loads, which can indicate possible problems. “We can chart that right on the HMI,” says Lutz. “If there’s a change in torque response on a specific drive, it can either generate a (maintenance) work order automatically, or it can raise an indication to the operator to get somebody out there to look at it before the next changeover.” Detailed machine data can also be monitored remotely.

In the end, the Criterion 2000 cartoner was able to achieve the targets set out by General Mills at the start of the project, including a 60 percent reduction in parts count and a 30 percent reduction in base price, compared to the previous generation machine, says Lutz.

The Gen3 technology is not needed in all General Mills cartoning applications. In situations where lines are running only a single shift daily or where high speed or flexibility is not at a premium, less capable, older generation machines will fit the bill, Lutz notes. But for many of the company’s mainstay products, for which lines are running three-shift, seven days per week operations, and where the need for flexibility is high, the Gen3 cartoner technology is the standard within General Mills, he says.

For these kinds of lines, “all of the projects that we have done since this development and the tests were completed, have been Gen3 machines,” says Lutz. “We have not bought any mechanical machines.” The company now has about 10 Criterion 2000 machines in use at various U.S. locations, he says, and expects to add more in the future as business needs dictate. “R.A. Jones has been selected as our alliance partner for cartoners,” Lutz adds.

What’s next? “We’re looking to apply the Gen3 technology to the rest of our packaging line,” Lutz responds. “We’ve done it on the cartoner. And now we’re looking at our other machines.”

See sidebar to this article: Price and Service are Gen3 Issues