ABB's Fully-Automated Modular Assembly Facility Produces Made-to-Order Motor Drives Every 20 Minutes

While phrases like global cell, continuous loop, modular assembly, escort memory, and dynamic buffering sound like futuristic adjectives for manufacturing processes, these terms are present and operational in a new, fully automated and modular assembly facility at ABB Automation Inc.'s drives production facility in New Berlin, WI.

In response to high demand for the company's new standard AC drive, the ACS/ACH 400, production is expected to reach 120-140 drives per day (up to 35,000 per year) at the site. ABB expects worldwide production of the entire ACS 400 Series (ranging from 3-50 HP) to reach up to 90,000 units per year, retaining ABB's position as the #1 manufacturer of variable speed drives.

Global Factories for Borderless Markets

"This is ABB's new 'Global Factory' for North America, virtually a mirror image of our new automated facility in Finland -- with a third cell nearing completion in China," said Kari Tikkanen, vice president and general manager of operations for ABB Automation Inc., Drives & Power Products Group, in Wisconsin. "These automated manufacturing facilities are regional, but they spring from ABB's global manufacturing strategy. This means that advanced ACS 400 AC drives can be installed and used by customers anywhere in the world -- and can be built and shipped from any of ABB's Global Factory operations."

This kind of production flexibility respects an economy, marketplace and product commonality that is borderless, Tikkanen said. "We think customers worldwide should be able to specify, order, receive, install and operate these low-horsepower AC drives in 24 hours or less," he said. "And, with standardized automated manufacturing facilities, these drives can be produced and shipped with only one day of lead time."

ABB's global production technique, noted Tikkanen, also reflects the reality of how engineers, OEMs and customers have come to think of, and use, low-horsepower drives -- as highly reliable standardized electronic components. "As part of ABB's common drives platform design, these units have now reached a level of technology and standardization that makes them extremely easy to use by anyone anywhere. They have a common operator interface and many standard features that are virtually 'plug and play'," he said.

Fast Continuous-Loop Production/35 Parts per Drive

ABB's highly automated, multi-level assembly line is installed on top of ESD, conductive carpeting, and built in a continuous loop structure so that production can proceed constantly without stoppage or interruption. "It's designed for extremely high utilization and output," said Tikkanen. "ABB is the only company in the world to be using this type of production in multiple locations for industrial products."

Drive frames are sub-assembled and then the assembler (one of the seven or eight personnel from newly formed Self-Directed Work Teams supporting the Global Factory) places specific assemblies on the line based on the drive product types needed. The flexible Global Factory builds whatever drives are required from a daily work schedule that is downloaded to the master control system. (Daily work schedules for the Global Factory are based on daily sales forecasts.) The drive sub-assemblies are placed on "smart pallets" that descend from one of the elevators of the continuously looped conveyor line. Each pallet has an electronic "escort memory" chip embedded in its base, which is programmed with unique assembly and production requirements for the specific model of drive that pallet carries. Pallets are then staged onto three conveyor lines, in a "dynamic buffering" arrangement that allows different models to be mixed and matched during the continuous production process.

"The 'smart pallets' allow the automated assembly line to remain flexible and totally modular," according to Rick Jasinski, manager of manufacturing engineering for ABB's New Berlin Global Factory. "The escort memory chip in the pallet dictates how each unit will be constructed and tested." That also allows the line the freedom to operate on a "pull production principle," Jasinski said, "with every pallet/drive able to proceed down the line only after the one before has pulled ahead. Smart pallet? -- yes. Smart production -- you bet!"

At two assembly stations adjacent to the staging line, all components required in each drive are installed. "The entire drive includes approximately 35 parts, and that's counting screws and the bar code label!" said Jasinski. "That's an advantage from an assembly point of view -- but, even better, so few parts ensures that there are a lot fewer variables when these drives go to work; fewer parts helps ensure reliability, longevity and performance when these drives reach our customers and are installed."

The "smart pallet" and drive then move automatically into a 4-axis robotic soldering station where, within three minutes, the drive's IGBT power plate and diode bridge are soldered. The pallet "escort memory" ensures that the robot receives model-specific data for the precise soldering required.

Automatic, Repeated Safety Testing

The pallet and drive then enter an enclosed chamber for high potential (HYPOT) testing, which includes applying 2,500 volts to check each drive's insulation. The drives roll on, into a 115º F Stress Chamber that is fitted with a high-speed robotic "manipulator" that can move at a rapid two meters per second. This 3-axis, track-mounted material-handling robot system loads and unloads pallets with drives within a floor-to-ceiling stacked-shelf room during the stress-testing sequence. To ensure thorough unit testing, drives first undergo a six-minute (cold-start) system test, followed by a one-hour powered burn-in test attached to an operating motor. A subsequent six-minute, full-load test concludes the cycle, and drives ready for shipment are then called out, fitted with cover parts, packed, and sent to shipping. In case of failure during this testing regimen, the system is programmed to park the drive in a repair location within the Stress Chamber. These units can be called out separately for inspection and/or repair.

Emptied "smart pallets" are shuttled by the conveyor up a tower to a holding area and across to the starting tower. When called, they descend to be fitted and reprogrammed for a new drive, and are ready to repeat the fully automated assembly and testing process.

"Production from the automated Global Factory includes ABB's R1-R4 frame sizes, which are NEMA 1 (IP 21) ACS 400, 380/480VAC drives in the 3-50 horsepower range, plus 230VAC units and NEMA 12 (IP 54) dust-and-splashproof drives ranging up to 50 horsepower," said Jasinski. "This site has raised the chinning bar for producing motor drives quickly and in direct response to customers' specific orders," he noted. "It points the way for the kind of responsiveness ABB and other companies will and can provide into the new millennium."