Frame of Reference

With more than 500 retail stores in 36 states, Eye Care Centers of America Inc. is the third largest retail optical chain in the United States.

To meet Eye Care Centers' retail demand, Camp Hill, Pa.-based parent company Highmark Vision Group (HVHC) has to produce huge quantities of eyeglasses in an array of configurations. To help meet increasing demand, HVHC opened a new production plant in Schertz, Texas.

“When we built our new plant, we installed several conveyors to move product throughout the facility,” recalls Ric Lee, HVHC's manager of quality operations at the Schertz facility. “One of the problems we had, though, was that we still had several smaller-volume material handling applications within the plant that were being addressed by people pushing carts between multiple locations. We couldn't figure out an economically and justifiable conveyor system that would work for those applications.”

That's when NCC Automated Systems Inc. of Telford, Pa., weighed in with some suggestions. NCC designed, configured and installed the conveyor systems for the new plant, and when HVHC told them it was looking for ways to make remaining applications more efficient, NCC showed them several options.

“They helped us identify and research a number of automated solutions,” notes Lee. “One that really grabbed our attention was an automated guided vehicle (AGV) system from Creform. It seemed like it might provide a better ROI than a conveyor would for these duties.”

The AGV system uses an adhesive-backed magnetic tape placed on the floor as the guidepath. The tape is read by a magnetic induction sensor mounted on the cart. Managers can change the path of the AGV by modifying the tape route.

The AGV system was set up to make a continuous loop around the production floor. As originally designed, the system consisted of 10 stations. At these stations, the AGV was loaded or unloaded with trays containing lenses or eyeglass frames, boxes of lenses, cases of frames or small totes of metal alloy. With the exception of the metal alloy, the items were loaded at eight stations and unloaded at two stations, which were devoted to operations support and shipping. Both unloading stations were positioned on the fringes of the facility, near the door.

The AGVs were programmed to stop at each of the 10 stations for one minute. However, HVHC wanted the ability to alter the material handling system by adding or decreasing stop times. Fortunately, the AGV system can be modified relatively quickly and inexpensively.

Quick and inexpensive, too, was the installation process. “We took occupancy of the new building at the end of March 2009 and were completely moved in by April 24,” says Lee.

Agnes the AGV

“Agnes was brought in and installed and was actually one of the first things on site. Agnes was running around the building before almost anything else was even here.

“We named the system Agnes, in part, because we never had an employee named Agnes, so we could not get her confused with someone or something else. It was just a joke at first, and we actually were going to have a contest to name the system, but everybody seemed to like the name so much that we stuck with it.

“It was up and ready in less than an hour after they got it here,” Lee continues. “Nearly all they had to do was lay the tape down on the floor. Actually, we have changed her path after we got it in here, realizing that the way we had penciled it in was not optimum for what we needed. Fortunately, NCC had left me some extra tape, so we simply pulled up some of the old tape, laid down new tape and rerouted her.” Lee says the facility is planning some reengineering in the coming months, so Agnes' job description will change yet again.

Of course, the old way that HVHC moved product — with people pushing carts — could also have been quickly altered, but there are some big differences. “With the old way, we sometimes had spoilage issues,” Lee explains. “You have stacks of trays on top of a cart, and you run into something, and the trays fall over, and then, you have lenses all over the floor. That didn't happen all the time, but you could always count on it happening at least once during a shift. Dropping 10 or 20 trays costs quite a bit of money.

“Also,” he notes, “the new system keeps people in their workstations. Each minute counts, as far as production is concerned, and when people are away from their production station pushing carts, that's a production loss.”

Conveyors keep people at their production stations, as well, but for small-volume applications, the AGV system is a better fit. “It would have been very expensive to put conveyors in those areas,” Lee says. “We looked into it and found that conveyors for just one of these applications would cost more than $140,000. The ROI on Agnes was less than six months,” Lee reports.

“In our business, ROI is vital, so any time you have something that is going to pay for itself in six months through labor and spoilage savings, that's a no brainer.”