Pump up the volume

Amplifier maker QSC Audio Products triples capacity so the tempo of manufacturing keeps up with demand.

By -- Modern Materials Handling, 2/1/2001

Did you hear pop star Ricky Martin perform his hit, "Livin' La Vida Loca," in his concert tour? Have you enjoyed half-time festivities at Superbowls? Or tuned in to the Grammy Awards or the Academy Awards?

Common to these and similar events are the high-quality professional audio amplifiers made by QSC Audio Products, Costa Mesa, CA. Demand for QSC amps is so strong that the company recently tripled its production capacity with the aid of extensive materials handling and data capture systems. Included are roller and belt conveyors, horizontal carousels, radio frequency identification (RFID) tags, and bar codes.

These systems are located in a 41,000 sq. ft. expansion to QSC's main plant. Open since July of 1999, the new assembly line in the expansion is a build-to-order, demand-pull operation, explains Bob Meigs, director of manufacturing. In contrast, the old assembly line remains a build-to-stock operation.

"What we do here isn't rocket science," he modestly declares. "But our new assembly line is a very controlled, paperless manufacturing process. It's designed to enable QSC to meet its throughput requirements."

Work-in-process (WIP) does rocket through the new facility in an enviable cycle time. Elapsed time spent from order placement to delivery of a finished amplifier to the plant's packout station is just 2 hr. On a two-shift-per-day production schedule, the new factory can turn out about 1,000 units each day.

The old QSC plant with its build-to-stock assembly line nearby moves at only half that pace. Its capacity is some 500 amplifiers per day. From start to finish, a work order for an amplifier model can take 1 to 4 days to arrive at packout on the old line. Many of these orders had to be scheduled 3 mo. in advance of production.

More equipment and more space for assembly operations help raise the new line's capacity, along with its highly automated equipment to build printed circuit boards.

Making the new line's production rate and short cycle time of 2 hours all the more remarkable is the variety of amplifiers assembled. "They come in all sizes and shapes," says Meigs. QSC builds a total of some 75 different models, plus it makes several advanced amplifier products.

"Our process is designed for manufacturability," Meigs explains, "so that the different amplifiers are easy to assemble and we can keep our quality high."

QSC relies upon smart conveyorized assembly with horizontal carousels feeding parts to assembly technicians in their work cells. RFID tags placed on WIP pallets create the capability to track each amp through production. And bar codes with serial numbers for each model that QSC assembles are the keys to releasing build instructions from databases to automated manufacturing systems, as well as to technicians in manual assembly cells on how to build any individual circuit board or amp product.

At the start of production, says Meigs, a single bar code is placed on the printed circuit board for the specific amplifier model to be made. The bar code contains part, revision, and serial numbers. When the bar code is scanned during assembly steps, the numbers are relayed to one of several databases. A host computer then sends instructions back to the line with all the information needed to build the specific product at the particular point of assembly.

This "recipe" procedure covers all the steps from PCB assembly through chassis assembly and testing and on to packout. At manual assembly workstations, technicians have computer monitors and use their intranet browsers to display what part of the recipe they need to follow.

To achieve this degree of control requires that multiple databases be networked, Meigs explains. The databases contain such details as parts required, assembly instructions, and test procedures for each amplifier model.

"All the data is readily accessible at various points on our assembly line," Meigs says, aided by the intranet browsers and monitors.

Assembly starts with building printed circuit boards on a highly automated line. A belt conveyor designed to handle these circuit boards moves them through the various production steps.

With the PCB built and ready to move on to chassis assembly and thermal testing, it is placed on a WIP pallet. Pallet and PCB are transferred from a belt conveyor to a roller conveyor in the final assembly area by two double-decker vertical lifts.

Relying on data read from the RFID tag embedded in each WIP pallet, which in turn is linked to the bar code data on the PCB for a specific amp product, the host computer then balances work loads. It directs a specific pallet to the appropriate manufacturing cell for further assembly.

Two horizontal carousels are located adjacent to the work cells. They provide a supply of empty amp chassises and other components to each cell.

"The carousels are a slick way to have all the parts in stock we need," says Meigs. "A technician just waits a few seconds for the right parts to come by and then picks them."

Replenishment is by warehouse employees. It also eliminates kitting of parts.

Few components are stocked by QSC. Instead, suppliers provide just-in-time service to the line. "On a Thursday night, for example," Meigs says, "we'll receive the parts we need to build amps on Friday. We're a demand pull factory."

During assembly, each chassis undergoes as many as 350 functional tests for quality assurance. "We get it right the first time," Meigs declares. Repair orders for mistakes made on the line are nearly nil, he adds.

System Snapshot
QSC Audio Products
Costa Mesa, Calif.

Plant builds high-quality professional power amplifiers and related equipment