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Manufacturing process designed for the global market.

Manufacturing process designed for the global market

Multipoint electronic fuel injection can provide engines with superior performance and fuel economy. The system precisely meters fuel to each cylinder in response to each ignition signal--providing smoother acceleration and near-perfect balance between performance and efficiency.

By adopting multipoint concepts, automakers in Europe, Japan, and the US can eliminate various component parts associated with aspirated engines and conventional fuel-injection systems. Thus, they can reduce production costs, satisfy consumer demands, and comply with environmental regulations--all strong incentives to adopt a concept that has evolved significantly over the past three decades and is now being refined by Siemens Automotive.

In 1988, Siemens AG, one of the world's largest electronics companies, acquired Bendix Electronics to accelerate development of advanced electronic control systems for the automotive industry. The result was the creation of a diverse automotive group that includes the Actuators and Fuel System Components Div, Newport News, VA, and Pisa, Italy. Currently, Siemens Automotive supplies 24 of the world's largest automakers with a variety of comfort and convenience products, engine-management systems, transmission controls, power-distribution products, electronic motors, and chassis controls.

To satisfy demand, the firm initially invested more than $38 million in production tooling with an additional $27 million to expand the setup at Actuators and Fuel Systems Components Div. Much of that investment covers production resources for the Deka series multi-point fuel-injection system, single-point injection systems, throttle-body assemblies, and fuel rails. The projected volume is nine million injectors by the end of 1991, and 12 million by 1994.

More than money

John G Sanderson, business development manager, fuel injectors, says, "We purchase the best equipment in the world, but our core competitive advantage has been created by the skilled people who operate that equipment productively. The role of the production worker has been expanded and upgraded to a professional level. We made a corporate commitment to building a manufacturing team with professionals that have the depth of skill to satisfy the needs of a world market. It begins with education and ends with a change in attitude to reflect a more global approach and understanding of our marketplace. It even includes our suppliers."

He adds, "We're trying to build an organization where the production worker merits equal respect with engineering and management. We feel that anyone who contributes to the welfare of our organization deserves respect. The challenge is to provide the right environment, provide the training to increase the depth and scope of personal skills, and give people the opportunity to exercise those skills."

Currently, production workers attend a wide variety of training courses during regular working hours. Many of these classes are completed for college credits. Equipment suppliers are expected to provide Siemens' employees with hands-on training in the operation and maintenance of their equipment. Here, engineering works with production people in a kind of group-technology task force, emphasizing teamwork.

John H Olson, manager, engineering production, notes, "We design our products to maximize the process, and the process includes the capabilities of our people as well as the production rates of our machinery. As our people become more capable and more flexible, Siemens becomes more competitive and more successful."

Automation aid

Helping Siemens Automotive achieve its objectives is a "silent partner," Mikron Corp, Monroe, CT. In the past four years, Mikron has provided the precise automated machining and assembly equipment and the skills training that make it possible for Siemens to satisfy global demands.

As John Sanderson puts it, "We expect our suppliers to be working partners, and Mikron has done just that. They have taught our people not only how to use the equipment, but how to service it to minimize downtime."

Fuel-injection systems and throatle-body assemblies are technically demanding. The parts must be machined to exacting tolerances. Injector components require near-perfect concentricity, unblemished surface finish, and the total absence of burrs.

To complicate production problems, critical injector components are machined in their "soft" state to gain the highest possible concentricity, the best surface finish, and to minimize grinding and lapping. The length-to-diameter relationship, component geometry, hole depth, and drill-point breakthrough into the fuel chamber pose a number of challenges for manual machining operations, CNC, and even robotic production lines. These challenges are magnified by the volume demand and by the diversity of fuel-injection-system designs.

According to Mr Olson, "Mikron's Multifactor machining systems and Polyfactor automated assembly systems gave us the production capacity to meet demand, but the real benefit was built-in quality control. Without this equipment, we could not produce the injectors to our high standards."

Multifactor rotary-transfer machining systems are in use worldwide to manufacture door locks, electrical components, appliances, automotive parts, and computer components--all on one compact high-volume production machining system. The versatility and performance of these systems can be enhanced with CNC processing units to reduce changeover times and increase throughput. At Siemens Automotive, four 8-station Multifactor machining systems are in operation, with each system producing more than 600 pcs/hr with indexing error held within 4 microns.

John Sanderson points out, "We ask a lot of the equipment, and, in the future, we'll be asking a lot more. We'll need flexibility. Every automaker may have a slightly different requirement. Flow patterns vary from split stream to pencil stream to conical. We work with each automaker to optimize a particular engine."

John Olson adds, "Our rotary transfer operates at a high rate with the ability to do front and rear machining and cross-hole machining in one setup. Something you just can't do with multispindle machines. Its rigid spindles and positive mechanical feel allow us to hold tolerances within a few microns, with little or no additional operations, resulting in low rejection rates. Finally, changeover time is short.

"The machines turn precise surfaces that become O-ring surfaces with no additional finishing operations. This capability cuts production costs and contributes to our concept of statistical process control. By holding tight tolerances and reducing manufacturing time and production costs through automated, multistage machining, we can produce high-quality parts at the lowest possible cost."

Assembly gage

The consistency is proved by Mikron's Polyfactor automated assembly systems. John Sanderson notes, "We cut traditional defects in half. Manual assembly allows you to put parts together with a great deal of slack, but this system gages tolerances of less than 1 micron, so it acts like a 100%, in-process inspection tool. The Polyfactor will assemble only those components that meet the standards."

To meet the standards, six Polyfactor systems are installed in an almost antiseptic environment. As part of its expansion program, Siemens constructed two Class 10,000 clean rooms with continuous submicron filtration and complete air change 72 times a minute. A third clean room is currently in construction to accommodate planned increased demand.

Flexibility of the systems allows Siemens Automotive to create a unique set of calibrations for each customer, then simply program in those calibrations when needed. With the help of proprietary software, each Mikron system automatically assembles the right design at rates of up to 20 pcs/min.

PHOTO : One of three Mikron Multifactor rotary-transfer machines producing 600 pcs/hr at Siemens Automotive. Inset shows Deka II Series multipoint injector.

PHOTO : Operations and sequence for machining fuel injectors. Drawing below shows details of Deka I fuel injector.

PHOTO : Conveyor line links Polyfactor assembly machines.

PHOTO : Finished fuel-rail assembly.
COPYRIGHT 1991 Nelson Publishing
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Copyright 1991 Gale, Cengage Learning. All rights reserved.

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Publication:Tooling & Production
Date:Nov 1, 1991
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