Coding Shipping-Tote the Rite Way

There are approximately two pick-to-light lines for every label printer/applicator, Atherton says, which is another reason the company needed highly dependable coding/labeling equipment.

"The printer/applicators' dependability was absolutely critical," he says. "It impacts our picking efficiencies because if, for some reason, a line goes down even for just an hour, our picking efficiency in that area can drop by up to twenty-five percent, because the totes would back up on the conveyor line, stuck in the pick module. The machines have been very reliable, and it's critical for us to have as much uptime on these machines as possible."

The stores order once a week, which amounts to 40 to 70 truck runs a day. When a store requests an order, the orders are put into picking "waves," which designate a set of Rite Aid retail stores. The DC sets up about six waves per day. When a wave's pick list is released to the order-picking operation, the pick lists are transmitted to a set of pick PCs located in the warehouse.

To initiate the picking process, an operator scans their identification badge using a Symbol hand-held scanner at a specific picking zone at the pick-to-light system, logs on and scans a permanently affixed, 10-digit identification code/license plate on an empty tote. This license plate information is then relayed into the PC, which marries the order pick list to that particular tote. The operator then puts the tote on a dead-roller conveyor and starts loading the desired number of items from the perspective rack, which is illuminated below by pick-to-light numbers on a digital display.

The picking system is complex, notes Atherton, with the barrage of multilevel mezzanines with conveyors running their length, carousels for split-case picking on a second-level mezzanine, light-directed put stations, a set of pick modules, eight cross docks, a bulk storage area, two pick tunnels and much more.

"There are ten pick lines arranged in four each-pick-from-caseflow rack modules," Atherton explains. "Two of the modules are two actual floor levels-high and the other two modules are three-high. Across from them are two more modules that are each-pick-frompallet-flow lines, which means orders here are split-case-picked directly from pallets. Each of those modules is three levels-high."

The facility uses two-way, rugged FP181 high-density polyethylene shipping totes from Menasha's Orbis Corp., that have two-piece interlocking lids. Measuring 21 x 14 in., the totes stand 12 in. tall and have slightly drafted bases.

The operator starts to pick a number of the packaged items from each "lighted" bay, loads the staged tote and then pushes a green light button to confirm that the items have been picked and loaded into the tote. Giving these the green light simultaneously updates the information on the PC.

When the tote order is complete, the operator places the filled tote onto a powered center section of the conveyor to exit the module. Or, if the system beeps twice, indicating the order isn't complete, the tote is passed to the next picker in line, in which case, a pick PC holds the information about what's already been picked and loaded in the tote and transfers the remaining picking data to the next pick station.

After an "exit tote" signal is sent to the picker, the completed, filled tote heads by takeaway conveyor to one of 12 Diagraph PA/5000 print-and-apply labeling systems. The "pick" PC also sends a message to the PC linked to the label printer/applicator. Stored in a local database that is called up when the totes arrive, the message indicates specific data that the PA/5000 will print in the form of a 20-digit bar-coded shipping label.

The shipping label contains a wealth of variable information, such as the 10-digit tote license plate ID code, which is also printed in human-readable characters beneath the code itself, plus a five-digit store code, the picking date, the wave number, the label applicator ID, a pick-list number and an operator log-on ID for all pickers who were involved with picking for the tote.

As totes approach the label printer/applicator, they pass a case stop and a singulation device that release just one tote at a time to pass through a pair of Accu-Sort Model 20 Series scanners mounted on either side of the conveyor belt. The scanners "read" the license plate ID for each tote and transmit the code to the label applicator control PC. The print information based on that data is then transmitted to the PA/5000, which automatically prints a 433-in. label from rollstock before the printed label transfers to an applicator pad. Emco furnishes the rolls of labels in quantities of about 1,200 labels/ roll.

As the tote breaks the beam of a trigger photoeye located at the printer/applicator, the system applies a label the top of the tote. And, as a precaution, every label's 20-digit shipping bar code is then scanned by a second Accu-Sort system to verify that the correct information has been printed and the tote exits the labeling area. Atherton explains, "If there's a software error caused by a bad scan, for example, the conveyor and labeler will automatically stop because the scanners are linked to the label applicator PC.

"The Diagraph labelers have a lot of internal error-checking functions, which is the main reason we selected them. If, for example, the print engine is turned off, or if labels aren't feeding properly, the PA/5000 will detect an error and, by means of an output on the machine, send a message that stops the conveyor. The Diagraph labelers actually combine our software error signals with their own internal hardware error signals and will halt the conveyor for either type of problem."

Since the plastic totes are reusable, the labels must stay in place during the typical 48-hour turnaround time, yet must be easy for pickers to remove when starting a new pick order. The system is programmed for a long tamp dwell of about 40 milliseconds, he says, to assure good label adhesion. Because the labels experience basically a two-day lifespan, Rite Aid runs the labelers in direct thermal mode, which eliminates the need for printing ribbon. "It's just one less thing to worry about," says Atherton.

Says McMahon, "Dealing with different applicating substrates, the label printer/applicators can experience a lot of wear and tear on certain components. This system has an auto retract sensor that provides the ability to print and apply labels to a variety of different product heights without having to make [manual] adjustments. The sensor compensates for the taller products, reducing the wear and tear."

After the labels are applied and verified, the totes convey into a Siemens Dematic RS 200 sortation system that runs 540 ft/min, sorting totes by store number, based on the code in the label applied.

The sorter disseminates the totes based on store number and the other information contained on the coded label, and the totes are then scanned overhead by an Accu-Sort Model 3600 camera-based scanner. They next head to a manual palletizing station.

The DC is impressed with the coding/labeling systems, Atherton adds. "The flexibility they give us is terrific," he says. "We're applying the labels, making pretty hard contact with plastic totes, so it's a tough application for labeling machines. But the PA/5000 units have withstood the test of time without any major maintenance problems. We plan to add at least one more machine that will service three additional pick lines."

Rite Aid Corp., Camp Hill, PA, ships items ranging from nonprescription health and beauty aids and cosmetics to small appliances. They are applying the labels, making pretty hard contact with plastic totes, so it's a tough application for labeling machines. But the PA/5000 units have withstood the test of time without any major maintenance problems.