Gear Up Machine Performance

By Scott Smith, Hartness International

Perhaps no industry is experiencing change as fast as packaging. Lighter-weight containers are being introduced to reduce costs and energy use. Packaging is redesigned more frequently to attract consumer attention in a competitive global marketplace. And manufacturers want to use fewer packaging materials to address environmental concerns.

In such a fluid environment, where new demands are being made every day, it pays to stay close to the customer. How to build packaging equipment from a customer’s point of view comes naturally for Hartness International.

Founder Tom Hartness started out as a Pepsi bottler in Greenville, S.C., in 1940, and soon was working on projects to improve the efficiency of the plant’s operations. A breakthrough came in 1945, when he invented a grid system for placing bottles in cartons. He began selling case packing equipment to other bottlers, and Hartness International was born. Today, Hartness has equipment at work in 160 countries and all 50 states, and a customer list of food and beverage and household chemical companies that reads like a Who’s Who of the world’s major consumer products manufacturers.

Constant innovation has led Hartness to a product line that extends far beyond case packers to encompass complete packaging lines. We’ve formed new Hartness divisions to focus on integration, robotics, automation, conveyors and production performance solutions.

Be Preferred. Innovate

“Customers want to go to one source for an integrated packaging line solution, and that means we have to continually evolve to stay competitive,” says Robert Beesley, engineering manager. “And since packaging is always changing, the systems we build are highly customized.”

Waste not Figure 1: The latest Hartness machine, GlobalShrink, targets the packaging industry’s need for systems that help to reduce the amount of packaging material used. Source: Hartness International

Our latest introduction, a shrink wrapping system, reflects the continuing evolution of the industry, which wants to reduce the amount of packaging material being used (Figure 1). GlobalShrink film-only multipackers and tray-former shrink wrappers are especially useful for manufacturers selling to club stores such as Wal-Mart, Sam’s and Costco.

“Manufacturers also want packaging equipment to perform reliability, be easy to monitor and diagnose line performance, and quickly change to accommodate different products and packaging requirements,” adds Beesley. “They also want to use fewer operators on their packaging lines.”

Keep It Simple

We use a design approach called “simple innovation” because it eliminates complex control schemes in favor of systems that are easy to operate and maintain. Lean engineering principles and cellular manufacturing techniques enable us to build a new machine in as little as 12 weeks from purchase order to shipment. We even make many of our own parts with steel that is laser-cut at our Greenville plant, and that gives us great flexibility.

The GlobalShrink platform demonstrates how we design packaging machines to achieve the extreme flexibility that customers demand. “Able to pack bottles on four-wall trays, on wall-less pads or with two-wall U-boards, or just with printed or plain film, these machines can be built to perform at 60, 80 or 100 cycles a minute,” states Beesley. “An 80-cycle machine running two lanes of bottles, for example, can pack 160 six-bottle packages every minute.”

Bottles are fed in a continuous process from the filler into the packer using a large conveyor. This mass flow of bottles feeds into a combiner that organizes the bottles in up to eight lanes, where a collator separates them into groups of the appropriate number of bottles. If a tray is required, the machine feeds a tray under each group of bottles, folds up the sides and hot glues the corners. Film is unrolled automatically and fed up and around each package. If printed film is used, sensors ensure that the film is correctly positioned on the package before a knife cuts the film. Each film-wrapped pack is then fed through a heat tunnel for shrinking.

“Controlling this complex set of movements at high speed is compounded by the trend toward lighter-weight bottles with thin walls that are softer and petaloid bottoms that make them unstable,” states Beesley.

“In a typical machine, our engineers use a combination of eight servomotors (3-7 hp) with attached gear boxes, five three-phase AC gearmotors (½-2 hp), encoders and dozens of photoelectric and proximity sensors to ensure precise motion control at all stages of the process.” The master controller is a PLC, and the brand we use varies depending on whether the machine is for use in the U.S., Europe or Japan.

Gear Reducer Is a Key Component

A gear reducer unit is used with each motor, whether it is integrated in a gearmotor or attached to a servo motor, to ensure delivery of the necessary torque. “Servos connected to gear reducers, for example, are used when timing is critical and rapid acceleration is required, such as when film is moving at 200 ft/min and must be cut precisely,” says Beesley. “In constant speed applications, such as filler machines requiring rotational movement, a gearmotor with encoder feedback has proven to be an economical alternative to servos.”

Before Hartness started to use SEW-Eurodrive gearmotors, we had to buy the motor and reducer and integrate it ourselves. It took 20 minutes more in machine assembly time and occupied 3 in. more space. This change also eliminated a coupler, so there’s one less potential point of failure. SEW provides us a more convenient, economical solution that has helped us to make our machines both smaller and more reliable.