Driven by need: Packaging tech keeps pushing the limits

Since shipping via air isn’t cost-efficient, most package molding won’t go to low-cost-labor regions, but high-volume and thin margins mean packaging molders still need all the tech they can get to turn a profit.

When Husky (HQ in Bolton, ON) opened the doors of its European campus in Dudelange, Luxembourg to show its latest packaging production technology, we expected to see some great stuff from the supplier with an estimated 75% share of the PET preforms business. But, said Husky, there would be no PET technology. Pardon?

Of the $843 million in orders Husky received in its 2005 fiscal year, 70% came from the packaging sector, including machines, hot runners, tooling, and everything else. Since the PET segment accounted for 49% of orders, that means 21%, a nontrivial $177 million, came from other packaging areas. This “other” was Husky’s focus in its technology open house, and includes everything from small yogurt cups to big material handling crates, as well as closures. Call it the un-PET forum.

Sectoring the market

Noting forecasts from Mastio & Co. of 5% average annual growth over the next few years in most major rigid packaging sectors, Husky VP of packaging Bruce Catoen made it clear that Husky is intent on growing in the un-PET areas. In fact, it plans to double its current level within three years, and its strategy revolves around two words: innovative technology. Further, that tech is all aimed at making its clients the low-cost producers in this ultracompetitive arena.

Husky has deep packaging roots. The company began making single-cavity thin-wall packaging molds in 1953 and was virtually a packaging-only supplier through most of the 1960s. When it saw that its molds could run faster than existing machines, it entered the molding machine business—with innovative technology.

At the Luxembourg event, Catoen showed a pie chart breaking typical package part production cost into raw material, capital amortization, operating costs, and scrap (opposite). Molders, he said, compete in six critical ways:

• Lighter part weight.
• Fast cycles.
• Higher cavitation.
• Labor reduction.
• Better equipment reliability.
• Consistent on-time delivery.

Maximizing the molder’s investment means 24/7 operation, no exceptions. As one molder wryly noted, “I make money Sunday night; the rest of the week I’m covering my costs.” Doing that takes a well-oiled, high-volume production system that simply does not go down. But it has to be nimble, too.

Catoen mentioned a molder who was bidding to make coat hangers for a large retailer, and the award was finally ready. And by the way, said the client, deliver in 16 weeks or eat the order. That kind of pressure keeps molders at the leading edge of technology, and hoping for more.

Are we at the limit?

Catoen says technological limits have been pushed way out over the last few decades, and it is now difficult to get substantial improvement in the usual places—for example, part weight. A look at his trend chart on part weight reduction (see graph) shows a flattening of the downward trend starting in the early 1990s. It’s a lot harder to cut a gram out of a cup after it’s already lost 10. Similarly, although the paring down of cycle time seemingly has no end, the time slices have become slivers.

Cavitation? Today’s high-cav stack molds let three molding machines make the 250 billion containers and lids/year that in the 1970s took a fleet of 22 high-end systems. (Upside: floor space.) In theory, increasing cavitation and reducing cycles could continue to reduce costs. Catoen wasted no time bursting that bubble: “We believe the limits of how many parts can be put into a given platen space have been reached.”

A few molders already are running four-level molds totaling 200 cavities, but if that’s not enough, what is? “The key to competing in this market is molding high cavitation efficiently, plus adding more value between the tiebars,” Catoen said. The technologies Husky is using to do that include integrated IML systems, tandem molds, stack molds, inmold handling, inmold closing, and faster cycling.

Integrated IML systems

Husky says the IML system first demonstrated at Fakuma in October 2005, and running during the Luxembourg event, is the fastest IML system available today—no small claim. Based on a hybrid 120-ton Husky Hylectric IM, it is a collaboration with German moldmaker and handling system supplier SysTec.

Perhaps the critical element in this system is extremely fast part extraction and label placement using swing chutes. But hold on: These are not Husky’s swing chutes, themselves quite fast.

SysTec’s swing chutes—one for takeout, one for label insertion, operating simultaneously—use servo actuation and a gear and cam design to achieve fast 180º rotation. Moving in sync with mold opening produces a mold dwell time of .03 second or less. Using a fast side-entry robot would increase cycle time by at least .5 second. The two-cavity mold made 200-ml, 6g rectangular food containers of 90-MFR polypropylene in 2.3-second cycles, yielding 3130 pph.

A second IML system based on a 120-ton Hylectric made 9.5g, 300-ml round cups of PP copolymer using Husky swing chutes for extraction and a high-speed Hekuma side-entry robot to place the labels. Cycle time for the Husky two-cavity mold was 3.5 seconds, yielding 2030 pph.

Molds in tandem

Husky developed its Quadloc Tandem (QT) machines originally for door panels and other large auto applications. The simple concept—put two standard molds in one machine and double its production—caught on in returnable large packaging like crates and pallets. Producing twice as much in the same floor space with about the same energy costs speaks for itself.

The platen linkage design allows for molds with different shut heights and dissimilar opening strokes. Assuming the mold thickness and opening stroke fit in the machine’s daylight, and a great many do, the tandem concept works well for collapsible crates. The base can be made on one side, the walls on the other, and the set can be robotically removed, assembled, and collapsed for shipment.

Husky says a review is under way for two-piece pallets using a common base and different molds for a variety of lids. There is enough interest in large-container applications that Husky added 2000- and 2700-metric-ton models to the QT Series, making a total of eight sizes from 1350-5400 tons.

Faster cycles for closures

As container production gets faster, closure makers need to keep pace. Closure cavitation has risen, too, but adding cavities doesn’t cancel the need for speed. Husky says cycle times have gone down about 25%, but will continue shrinking. A 1-second reduction can boost output up to 25%. Stack molding is becoming more accepted, and Husky has some 2+128 projects in the inquiry stage and a 2+96 already running in North America.

Rising material costs are driving change in closure designs. Two-piece sport caps are being replaced by one-piece designs with an integral hinge connector. Similarly, two-piece carbonated soft drink (CSD) closures are moving to a one-piece design, cutting 10-15% from the cost. Husky had two closure systems running during its Packaging Days, each based on a 300-ton Hylectric hybrid. In one, a 48-cavity mold from Corvaglia (Switzerland) made 38-mm closures in 4.6-second cycles. In the other, a 64-cavity mold from Austrian moldmaker KTW popped out 28-mm closures every 5.2 seconds.

Husky says shot-to-shot repeatability in both Hylectric systems exceeds 99.8%. The credit is given to the accuracy of the machines, but not solely. Hot runner balance is not only essential for high-cav molding, but it also becomes more important as cavity numbers increase. Jean-Michel Cunche, Husky’s hot runner manager for closures in Europe, said an unbalanced hot runner means tolerances cannot be met, parts won’t eject symmetrically, and mold life suffers. “The hot runner has to be both thermally and geometrically balanced when you have such small parts.”