Shuttle cars drive efficiency at Procter & Gamble: automatic guided vehicles drastically cut forklift use at the personal-care facility in Iowa City - Procter & Gamble - Cover Story

Food & Drug Packaging, April, 2003 by Pan Demetrakakes

STAT AT-A-GLANCE

Company: Procter & Gamble

Location: Iowa City, Iowa

Operation: Three shifts, seven days a week

Products: Shampoo, conditioner, mouthwash

Packages: Tubes, bottles

Taxis are nice, but buses save money.

That principle has been successfully translated into material handling at the Procter & Gamble plant in Iowa City, Iowa. For most of the journey to mid from the plant's packaging lines, loads travel not in forklifts, but in automatic guided vehicles (AGVs) that wend through the plant in continual, unmanned loops.

The Iowa City facility furls 24 hours a day, seven days a week, producing a host of high-profile P&G personal-care products. Leading P&G brands in this category include Head & Shoulders, Pert, Pantene, Clairol Herbal Essence, Physique, Aussie and Infusium haircare products and Scope mouthwash.

Connecting the plant's many packaging lines with its warehouse space ordinarily would require a fleet of forklifts. But Iowa City plant personnel have cut down considerably on forklift requirements by successfully establishing and maintaining an AGV system.

The AGVs cruise automatically at short intervals between the warehouse and the plant. They pick up empty bottles, corrugated flats and other packaging materials from storage and deliver them to the packaging lines as needed, taking back unused packaging and scrap. P&G recently installed another AGV loop to transport pallet loads of finished goods between the packaging lines and the shipping docks.

The AGV system, from AGV Products Inc., has greatly increased the efficiency of the Iowa City plant's material handling. Before the finished-goods AGV loop was established last year, there was a driver for each palletizer; now two drivers are enough for the entire finished-goods portion of the warehouse.

"AGVs are all about moving things more efficiently," says Jen Olsen, the plant's material supply manager. "If we didn't have the AGVs, we'd have an army of people moving things around in our warehouse."

Earlier problems

AGVs weren't always a smooth ride, at Iowa City or for P&G in general. Several other P&G plants tried AGV systems in the 1980s, but had to abandon them due to chronic breakdowns. Iowa City managed to keep its first AGV system going through the late 1990s, but eventually it, too, was overcome. The problems included difficulty in getting spare parts (which had to come from Europe), a control software supplier who went out of business and a design that depended on contactors that controlled vehicle speed and that kept burning out.

The new system was easier to install and runs much more reliably. The cars run along a wire embedded in the plant floor. When the second loop (for finished goods) was installed last year, disruption was minimal, says Steve Parizek, the Iowa City plant's AGV supervisor. Cutting a small trough for the new wire and resealing the floor took a couple of days; the major effort was programming the software and reconfiguring the warehouse to create new aisles for the AGVs.

Loads beading from the warehouse to the plant always are taken by forklift to a staging area, an automated roller conveyor that serves as one of the stops on the AGV route. Synchronized photoelectric sensors form a "handshake" to insure the AGV and load conveyor are lined up for load transfer at the staging area, and the load is transferred automatically into the vehicle. In some cases, the AGV takes its cargo directly to the beginning of the packaging line, where operators load the closures, bottles and other materials into the proper machines. In other cases, a forklift takes the supplies from a nearby staging area to the line.

The success of the plant's AGV system depends on efficient interfaces among the AGVs, the forklift drivers and the lines. The most important interface is between the system that guides the AGVs and the plant's broader material-handling software. The former is known as TRACE (Traffic Routing AGV Command Executive), which AGV Products supplied with the vehicles; the latter is RTCIS (Real-Time Control Inventory System), a software package that P&G developed in-house.

These two software applications, working together, constitute the brains of the AGV system. "AGVs don't know what they're hauling," Parizek says. "All they know is, `I've got to pick up at Point A and drop off at Point B.'"

How cars are called

Most of the calls to TRACE come through in one of two ways. Certain conditions generate automatic calls--for example, when a photoelectric sensor at the end of a packaging line indicates that a supply of packaging materials is depleted.

TRACE relays the message to RTCIS, which translates it into an order to a forklift driver's on-board terminal. The driver takes a load to a staging area as directed, scanning the bar code on the wrapped pallet load for the system to verify. TRACE then directs the load to be transferred onto an AGV and taken to another staging area.

The AGVs help keep Iowa City's packaging lines humming at top speeds. High volume is an imperative at the 40-year-old plant, which undergoes frequent changeovers that entail everything from changing out conveyor and machine parts to flushing out fillers.