Thursday, December 31, 2009

Plant Engineering: Manufacturing Perspectives at Automation Fair

This is from Bob Vavra of Plant Engineering. Read what he tells about manufacturing perspectives at automation fair.

1. The power of the plant floor:
The opening day of Rockwell Automation’s annual Automation Fair in Anaheim on Tuesday featured a day-long series of discussions on a global view of manufacturing issues. The morning session of the Manufacturing Perspectives series painted a strong picture of a manufacturing economy emerging from a deep recession and already showing signs of life with 2010 just around the corner.
It also pointed again to the power and visibility the plant floor is receiving from automation vendors, IT professionals and business leaders.

In his opening remarks Tuesday, Rockwell Automation CEO Keith Nosbusch pointed to the shift in manufacturing “from an IT-connected manufacturing system to an optimized plant floor and supply chain network. The plant floor is where power, control and information converge. The factory floor becomes the focal point.”

2. The globalization of manufacturing:
Nosbusch said that Rockwell’s goal was to have 60% of its business outside the U.S. by 2013. Already, he noted that more than half of Rockwell Automation’s employees are outside of the U.S.

While some of our more short-sighted commentators view this as “off-shoring” jobs, Jeremy Leonard of the Manufacturers Alliance/MAPI noted in his remarks that there is good off-shoring and bad off-shoring. “Most of the off-shoring is the former,” Leonard said. While conceding that high-value, low-piece products such as computers and electronics are manufactured to take advantage of labor costs, he said the vast majority of expansion in emerging markets such as China, Indian and Brazil is to serve the local and regional markets. He added that transportation costs have driven many manufacturers away from simply off-shoring jobs and production because of the increasing costs of getting those products back into the supply chain.

3. Issues and opportunities:
Leonard cited four major reforms manufacturers need to improve their operations - and all of them were legislative in nature: reducing tax rates (which he said was “the single most important barrier to competitiveness”) heath care costs, tort reform and regulatory compliance. But he also said American manufacturing suffers from lower levels of research and development than most other industrialized nations and are drawing on a smaller skilled labor pool. His research finds that U.S. engineering degrees are down 20% in the last two decades and that 40% of current 9th graders will lack the skills needed in modern manufacturing.

4. The good news is:
“The manufacturing recession is over,” Leonard said. While growth will slow in the fourth quarter because the stimulus packages, especially Cash For Clunkers, will not be present in the fourth quarter, MAPI is still anticipating 2.4% growth for the year and predicts slow but steady growth over the next five years. Build into that is a slower but still steady drop in the unemployment rate. But he does not see a lot of new construction in the coming months in manufacturing. “Plants will be putting idle capacity back on line rather than building new capacity,” he said.

5. And the quote: Leonard takes a dim view of those who claim U.S. manufacturing is not a major player in either the national economy or the global market. “U.S. manufacturing is the engine for growth in a global economy,” he said. “Manufacturing is not becoming less important to this economy. What matters is the volume of things made. We’re simply producing more with fewer resources.”

Monday, October 5, 2009

Preventive Maintenance: Replacing Incandescent Lamps with LEDS

Currently, there is interest in high efficiency, long-life, light emitting diode (LED) lamps for use in factories, institutional, and commercial applications, because the costs of electricity for lighting and labor for bulb replacement are significant. The goal of the LED manufacturers is to build a very high-brightness white LED that is economical and efficient enough to be used for illumination. To gain widespread acceptance as a legitimate light source for general lighting, LEDs must be able to economically and reliably deliver illumination levels of white light of a quality within today's acceptable standards.

Theory of operation

An LED is a PN junction semiconductor that emits photons when forward biased. The emission of light occurs when minority carriers recombine with carriers of the opposite type in the band gap of the diode. The wavelength of the emitted light — which determines its color — varies according to the semiconductor material.

LEDs are processed in wafer form similar to silicon integrated circuits, and broken out into dice. The simplest packaged LED is the indicator lamp. Typically, LEDs have a mean time between failures (MTBF) of more than 100,000 hr.

Today's ultrabright LEDs exceed the light output of incandescent and halogen lamps. They don't have the maintenance requirements associated with filament lamps. LEDs can be dimmed using a pulse-width modulation (PWM) circuit, which delivers energy in pulses of varying duty cycle.

History of LEDs

The first reports of a device with properties similar to LEDs dates back to 1906 when Henry Round reported electroluminescence while experimenting with carborundum. However, LEDs didn't become commercially available until the early 1960s. Texas Instruments sold an infrared (IR) device for $130 and GE distributed red LEDs through the Allied Radio catalog for $260. They were expensive and sold in low volumes.

IBM used LEDs as on-off indicator lights on circuit boards in a mainframe computer constructed around 1964, which marks the first time LEDs were used to replace incandescent lamps. LEDs used less power, could be mounted directly on the circuit board, and had a much longer life expectancy, which made using LEDs attractive from a maintenance perspective.

In the mid 1980s, the U.S. military began gradually replacing tungsten filament indicators with LEDs, and they began appearing in elevator cars. As with the IBM application, LEDs were designed into pieces of equipment. They were mounted on printed circuit boards (PCBs), mounted in equipment panels and face plates using specific mounting bezels with wires soldered to their leads, and plugged into sockets made specifically for LEDs.

LED performance made a leap in the early 2000s. Companies started manufacturing flashlights using LEDs instead of the traditional incandescent bulb. As improvements were made in brightness and color, LEDs moved farther into tungsten territory. They appeared in traffic signals, home entertainment, and decorative lighting.

Today, LEDs are used in many industries from automotive to architectural lighting applications. Industrial plants are discovering the benefits of replacing traditional bulbs with LED lamps. For example, hundreds of incandescent lamp part numbers now have direct LED-based replacements. Most LED suppliers have extensive cross-reference literature and databases. Standard lamp bases are available, allowing LED lamps to replace incandescent lamps without having to retrofit equipment.

Flashlights continue to get brighter. Some currently available flashlights suitable for industrial use boast as much as 1800 foot-candles (fc) of white light. LED floodlights, work lights, and luminaires for general-purpose lighting applications are available as well.

Benefits

LEDs have enjoyed continued success because they use considerably less power and last much longer than tungsten filament incandescent bulbs. LED lamps use only 10% to 20% of the energy consumed by equivalent incandescent lamps. An average LED life span can exceed 100,000 hr — more than 11 yr.

LEDs are solid-state devices, which make them virtually immune to electrical and mechanical shock — unlike incandescent lamps, which have filaments that are very susceptible to electrical and mechanical shock. Electrical shock comes from constant on-off transitions, transients, and surges; mechanical shock comes from bumping, jarring, and other forms of vibration. Also, LEDs produce very little heat, making them an attractive alternative to incandescent lamps in applications where heat is an issue, such as biotechnology, chemical, and food processing.

Issues

LEDs had to overcome physical and technological issues to get where they are today. The primary hurdles have been drive current, packaging, color, and price. Although these issues have been addressed, they still exist to some degree. Drive current directly affects LED lamp output and lamp life. LEDs are inherently robust. They are capable of delivering high output at high current, as long as heat is extracted properly.

Packaging issues include thermal management, current handling capability, and color. Advanced device packaging allows adequate heat dissipation and increased current capacity. Packaging also affects color, which is extremely important in applications that require white light. Use of LEDs as illumination sources requires white light with a degree of "warmth." This requirement must be met if LEDs are to make any headway in replacing incandescent lamps for general-purpose illumination. Fluorescent lighting addressed this issue. And it appears that LEDs are rising to meet the challenge as well.

The cost-effectiveness of LEDs depends on the application. Today, the system price is high for replacing conventional incandescent lamps with LED-based technology. However, for established LED applications, such as control panel indicators and annunciator lamps, LEDs are more cost effective. Although the unit price is higher, the lower power consumption and longer lamp life help offset the initial purchase price. Some plants can justify the higher cost of LEDs for this application based on lower maintenance costs alone.

Source: Plant Engineering Magazine - January 1, 2005

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