Wireless enables assembly lines

802.11 LANs, RFID and sensors let factories peer into plant processes.

Manufacturers large and small are starting to cut the cords in their respective factories and plants. The installation of wireless sensors, RFID and 802.11-based wireless is helping these firms gain better insight into production processes, inventory and product movement.

Wireless sensors facilitate an architecture where machines, and even inanimate parts and products, can be connected and monitored. This lets manufacturers track the health of factory equipment, the movement of products along an assembly line and the delivery of inventory. Other companies are putting a combination of 802.11 and RFID technology to use, allowing for similar end-to-end product life-cycle tracking.

"Plants are moving away from being a single-purpose facility that produces the same thing all day long for distribution all over the world," says Robert Parker, an analyst with Manufacturing Insights, an IDC company that tracks IT trends in manufacturing.

The other push toward the use of wireless sensors in factory networks is to give companies the ability to remotely monitor and control what's going on in far-flung plants.

"Manufacturers are looking to get a compressive view of how all their operations are interconnected," Parker says. "If you have a more flexible plant, producing a lot of products spread out over a wide area, you may have to have expertise centralized into a few locations for supporting plant technologies. The challenge is how to remotely manage these things."

General Motors is deploying several wireless technologies to meet this challenge. GM is moving toward outfitting its plants with everything from sensor network technology, including RFID tags on its inventory, to mesh networks. The combination of these technologies will help GM track everything from the parts that go into GM vehicles to the robotic assembly device and other heavy equipment used to put the cars and trucks together.

"The issues that define e-manufacturing are: how real-time data is obtained and what you as a company do with this real-time data," says Pulak Bandyopadhyay, group manager for plant floor systems and control group in GM's Manufacturing Systems Research.

GM is starting to deploy sensor technology in its plants to measure the health of its manufacturing equipment. Devices can be deployed with stamp presses, conveyer belts and other types of machinery that measure vibration, heat and other factors that can be detected to predict when a machine might fail or require service. Having the ability to detect when a piece of machinery in a plant in Mexico might go down from a network operations center in Detroit will help GM save on maintenance costs.

GM also is looking into linking such plant floor gear with mesh-based network equipment. A mesh will let network transceiver equipment act as individual wireless routers, connecting any device to any device on the most available path. This would allow telemetry data to hop from node to node on the network, instead of all data tying back to a few wireless access points. The result would be a plant where equipment can be positioned anywhere and stay online without wires.


The worldwide market for industrial-grade network gear is expected to grow from $124.4 million in 2004 to $939.8 million in 2009, according to ARC Advisory Group.
A survey of 300 manufacturing companies by Datamonitor showed that 60% of manufacturers are already working on RFID projects, while 90% of manufacturers said their next RFID project will be based on systems and data integration.
U.S. manufacturers spent around $77.1 billion on IT last year, according to IDC — a 5% uptick in spending from the year before.

Although he does not like to discuss exact dollar figures or product brands, Bandyopadhyay estimates that wireless technologies GM is rolling out can help save 10% to 20% on production costs. This is because of the improved efficiency of workers in plants and other facilities outfitted with various wireless gear, such as workers on plant floors with Wi-Fi PDAs, as well as wireless-based telemetry equipment for monitoring machinery. When coupled with systems on the back end that help analyze and deliver business information based on wireless data collected, another 10% to 20% increase in efficiency and productivity could be possible.

Another area that wireless technologies is being rolled out at GM is in inventory tracking.

What GM is moving towards is this, Bandyopadhyay says: "having the ability to track the deliver of components of [a car or truck] to the factory, and then to track the assembled cars from the plants all the way to the dealership." This will give GM real-time visibility into its entire supply chain, as opposed to waiting for month-end reports on the movement of parts inventory and vehicle inventories and production.

One impediment to wireless deployment in manufacturing environments is the reliance on many proprietary technologies. Standards, such as 802.15.4, or Zigbee , are emerging as ways to tie together independent wireless nodes into a mesh, where any device can transmit and receive data from any other device. However, factories rely on a myriad of wireless technologies, ranging from 900MHz to 2.5 and 5GHz to control equipment and devices.

"We could implement wireless more broadly right now in our facilities, but [we] would end up with over 30 different networks that are incompatible," Bandyopadhyay says. GM is working with other manufacturers to promote the use of 802.11 standards in wireless-enabled industrial equipment.

Smaller manufacturers also are getting into wireless sensing and inventory identification. Lifetime Products, which makes outdoor furniture and home sports equipment, uses a mix of standard 802.11 and RFID to get a better look into how products move inside factories and among different buildings.

In its 27 facilities, located on a single campus in Clearfield, Utah, Lifetime has deployed a mix of wireless technologies that let the company track its inventory of components as they move through various manufacturing products, and then follow the finished items as they are stored and shipped, according to Lifetime's CIO, John Bowden.

On the manufacturing side, wireless cards are deployed with primary logic controller (PLC) equipment in the factories. PLCs control the actions of devices such as laser cutters, for creating plastic seats and basketball backboards. Manufacturers can feed real-time data back to Lifetime's data center, letting analysts know at any given time exactly how many products are being produced and at what rate. In the past, this data had to be extracted from machines on the plant floors via serial devices or floppy disks. The data might have been available to view on a printed-out spreadsheet after a month or so, Bowden says.

On the inventory side, HP ProCurve wireless LANs and RFID are being combined to track products after they are finished.

"What you have are forklifts that are roving up and down inventory isles," Bowden says. "They have tablet PCs or a wireless laptops and they're using a Wi-Fi signal to communicate. The concept is that the RFID tag is read and its input directly into our ERP system via the wireless [access points]."

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Copyright © 2005 IDG Communications, Inc.

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