Stackers and Palletizers — Making Perfect Piles

By Erik Cagle

The workflow process of a commercial printer is a lot like a 4x400 relay team in track and field: all the components of the team must be equally strong in order to be successful, and the final step is as important, even more so, than any other. After all, you don't want the anchor leg dropping the baton.

The world of stackers and palletizers is the equivalent of the anchor leg, as it prepares finished product for delivery. Thus while not as ballyhooed as the sexier prepress parts of printing operations, its customers demand the ultimate in reliability, durability and performance.

"Many plants run their equipment for multiple shifts; some run around the clock," notes Leslie Figler, marketing manager for Gämmerler. "As a result, printers require stackers and palletizers that can run day in, day out and still provide a consistently high level of performance."

Gämmerler has unveiled three new compensating stackers: the PrintPath STC-700 (an update of the STC-70 model), the KL 5000 (update of KL 507) and the indexing/compensating stacker KL 6000. Features include a multilingual control panel, an open turntable designed to prevent jams and large window-style guards for viewing machine operation.

Minimize Lifting

Gämmerler's latest palletizer offering is the PowerLift. The machine provides efficiency and improves productivity by helping operators pick up multiple bundles simultaneously with minimal lifting force.

Flexibility is a key ingredient in the stacker selection process for printers, according to Matthew Roskam, executive vice president for Roskam Automatic Machinery. This entails handling various product widths and characteristics.

Palletizers must also have flexibility, as well as user-friendly characteristics. "Printers are not interested in a system that is complicated to run, or that requires constant adjustment or tool changeovers," Roskam says. "Therefore, a system should handle the complexity for the operator and provide a simple, yet powerful, interface for the entire system."

The Roskam stacker has a control package that features touchscreen interface, along with a modular out-feed approach. This can, for example, allow a client to upgrade a manual offload stacker to one that can interface directly with a robotic palletizing system.

Roskam palletizers, with rugged conveyor construction, feature a package with PLC, PC and robot controls seamlessly integrated. All elements of the robotic work cell are controlled from a single touchscreen interface. The interface doesn't require the operator to directly interface with the robot controller.

The palletizer's footprint is a significant consideration in analyzing palletizers, according to Robert Stock, technical sales engineer for Kolbus America. Kolbus' DOCTOR line of automatic palletizers can handle various products, including bookblocks, perfect bound books, saddle stitched magazines, parcels and cartons.

The DOCTOR 20 boasts an elevator-type infeed. Built with single products, bundled or shrink-wrapped piles/cartons in mind, products can be turned 90 degrees left or right with speeds up to 20 cycles per minute.

The DOCTOR 30 was designed to palletize loose and slippery product piles with a height of 300mm. It reaches speeds of 30 cpm, and its transport unit turns products 90 degrees or 180 degrees to achieve desired pallet pattern.

With customized publications becoming more prevalent, shorter print runs are demanding speed and reliability more than ever, according to J.C. Anson, division manager, print finishing, for Muller Martini. Other considerations that factor into the decision-making process for customers include profitability, as well as the ability to handle diverse product, provide durability and reliability, and churn out quality work.

An ergonomically sensitive machine is also critical, according to Anson. "By combining stackers, palletizers and other labor-saving components into an in-line workflow, Muller Martini can eliminate the need for human interaction with the printed product. That means no lifting, no bending, no strains and no sprains."

Multiple Stackers

On the stacker side, Muller Martini offers a bevy of options. The Apollo compensating stacker can be placed in-line with any saddle stitcher or trimmer to produce at a rate of 14,000 cycles per hour. The Rapido compensating stacker handles stitched products and newspapers at a rate of 20,000 cph. The 1534 Uno counter stacker connects to any perfect binder or three-knife trimmer and combines counting, jogging and stacking into one automated operation at a rate of 16,000 cph.

The CB-16 compensating book counter stacker connects with perfect binding systems to handle finished magazines, brochures, telephone directories and other adhesive-bound products at a rate up to 18,000 cph. The Forte (120,000 cph), designed for use in web offset or gravure pressrooms, processes magazine and catalog sections, TV programs, flyers, shoppers, newspaper inserts and commercial work. The Book Line Stacker Delivery (BLSD) 600 stacks hard-case products and book blocks at a rate of 63 cycles per minute.

On the palletizing end, Muller Martini offers the Cohiba, which offloads finished product onto standard pallets at rates up to 26 stacks per minute.

Keeping pace with the press is a virtue many customers value, according to Bill Stiles, sales and marketing manager for Advance Graphics Equipment (AGE) of York. "AGE units are portable, so maneuvering from press to press is done easily," he says. "Continuous running capabilities at press speeds reduce waste and increase profitability."

AGE's high-pile stacker is designed as a modular unit to receive streams delivered from a sheeter and stack them into neatly jogged vertical piles, with standard heights of 32˝ and 40˝. The unit is portable and can be used on any press sheeter with a minimum of makeready time. Features include air-actuated rear insert interposer rods for on-the-run pile removal up to 1,200 fpm. Optional batch conveyor and chipboard inserter units are also available.

Personnel Reduction

Reducing added manpower at the end of the finishing line is a critical issue for choosing a stacker these days, according to John Salamone, president of Nu-Tech Printing Machinery. "Since plants have downsized, they don't have the available personnel to batch and band," he notes. "Therefore, they hire temporary workers on an as-needed basis. Depending on a temp pool is both expensive and a scheduling problem."

Nu-Tech offers the BSB/2000 stacker, which can count, batch and band in 4.5 seconds per batch. It handles standard sizes from 3x5˝ to 81⁄2x11˝.

The RPS/2000 turns the existing rotary cutter into a sheeter capable of trimming all four sides of the flat sheet. The RPS/2000 also stacks both one- and two-stream flat work on pallets at the end of a rotary cutter. Nu-Tech provides a third stacker, the SB/2000-E, which batches an assortment of products at a greatly reduced cycle time.

While pricing wars for equipment are prevalent across the print production platform, service is a major variable for the customer, according to Ric Mayle, vice president of sales and marketing for IMC America. With more than 2,000 Civiemme systems installed worldwide, IMC markets, sells and provides parts and service.

The "Cadillac" of IMC's stacker/bundler offerings is the Civiemme ST420, which features a PLC control system with operator interface panel. The machine includes maximum bundle lengths of 40˝ or 48˝ and variable speed drivers with inverter-controlled AC motors synchronized to press speed.

Simplicity is the key in diagraming these systems, according to Mayle. "Most people on the end of these high-speed web presses do not have a lot of skill," he says. "For any of these automated machines, you need to have some mechanical ability, so the direction we've taken is to make adjustments and operations as simple as possible. It should be as user-friendly as possible, and limit manual intervention."

IMC's PL86 palletizer features a pneumatic clamp with motorized pads. The system boasts PLC programmed automatic functions and settings.

Reducing manpower and simplifying operation is key for any system, agrees Dave Benjamin, Eastern regional sales manager for Systems Technology (STI). The LoadBuilder2 automatic palletizer system from STI features simple interfaces with existing horizontal and vertical stacker bundlers. The system can be designed to palletize bundles that are exiting from several stackers. It has optional automatic pallet feeding and placement designs. Pallet rotation is also available.

STI also offers the Model 195A automatic vertical stacker bundler that features bad copy gate, vibrating belt jogger, crusher roller, patter jogger and gapper mechanism.

Another offering, the Gremser line of stackers, was unveiled for the first time in North America at Graph Expo 2002, reveals Wayne Pagel, president of KEPES Inc. The line boasts a sheet performance of up to 10,000 sph, with high-speed applications up to 15,000 sph. Among the Gremser line's features are trailing edge downforce for high-speed applications, air cushion for long and soft sheets, sheet rejecter, twin sheet delivery and a second set of jogger paddles for long sheets.