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New technology means greater precision, capabilities for engine casting manufacturer.

Machining is an expensive and time-consuming process that most manufacturers would dearly like to avoid as much as possible. As a result, the pressure is on suppliers, particularly those such as foundries or forges, to improve their ability to provide components with reduced machining requirements.

Golden Casting, the Columbus, Ind., gray iron foundry, has taken a giant step toward greater casting precision with the installation and commissioning of a new sand core-making system used in the manufacture of high volume heavy-duty diesel engine blocks.

"We can really say that there's nothing else quite like this in the world," said Bo Witt, vice president of sales and marketing at Golden, which specializes in head and block castings. "Since we installed the system in late 1997, we've been able to continuously improve our processes to the point where we are beating the competition worldwide."

The new system, said to be the largest of its kind ever built by Vitoria, Spain-based Loramendi, S.A, is specifically designed to produce cores for diesel engine block castings between 8 and 15 L. The fully automated system, which covers about 25,000 of Golden's 338,000 sq.ft. facility, incorporates a large 1900 x 900 mm core box on a vertically parted core machine, a key-core machine, a core dipping station and a core wash drying oven. Complex shaped crankcase core sections are produced by the core machine and assembled by a pair of robotic manipulators. The key core is then blown into the crankcase cores to lock the package together.

Four cores can be made simultaneously and after they are assembled, the cores are placed in molds and transported to the pouting area.

"The Loramendi machine is essentially able to make an entire core package in two core boxes," said Witt. "On the 14 L engine core package we're making with it now, there are eight cores in the package. The machine makes the front half in one shot, the back half in the second shot and puts them together to make the completed core package.

"In the past, we would have had to make eight individual cores and bolt them all together to build up a single casting. That allowed for a lot of variation between the individual cores in a single casting, and from one casting to the next. It was something that couldn't be avoided and as a result, people would design block castings with as much as 6 or 7 mm of machine stock to allow for the variation. Then they'd have to machine it off to get the tolerances they were looking for.

"The Loramendi process allows us to be much more precise. Engine manufacturers can design much thinner walls and not have nearly as much machining."

Witt said the dimensional variation between cylinder bores on a block casting produced on the Loramendi system is [+ or -]0.2 mm vs. as much as 0.75 mm with conventional core-making processes. "And the cores are vertically parted instead of horizontally parted," Witt noted. "The fact that in the past cores were produced horizontally was one of the classic problems.

"The vertical parting removes all the imperfections from the core that are made by the mechanical parts of the core box. This produces a smooth core surface and therefore a smooth casting surface. With thinner casting walls, the smooth casting surface is necessary to eliminate stress raisers."

Golden is currently manufacturing three blocks, ranging from 12 to 15 L with the heaviest weighing 800 lb., on the Loramendi line. Tooling to move from one core box to the other can be changed in as little as 30 seconds, as opposed to nearly three hours previously.

"It's amazing how much more productive this system has allowed us to be," said Witt. "Our ability to produce high volumes quickly has also been a great benefit to our customers. We're able to manufacture and ship engine blocks on a just-in-time basis, and adjust our output to their requirements."

Witt said that in some Loramendi applications, customers had reduced their block machining costs by as much as 33 percent because of the increased precision brought about by the system. It also improves the throughput of their block machine line, he said, noting "that's usually where the bottlenecks occur."

The greatest advantage of the Loramendi system is realized with a new block casting design, Witt said. Through concurrent engineering, the weight of the engine block can be kept to a minimum. "In our most recent new product introduction, the weight of a new block casting was reduced by 15 percent," noted Witt. "In real terms, it was something like 113 lb. That's a tremendous cost savings both in terms of material and machining."

The Loramendi system is the latest in a continuing line of manufacturing improvements made at Golden over the last few years. Golden has a long history in the engine business, beginning in 1915 as the Columbus Casting Co. The only large independent foundry remaining in the U.S. that produces high- volume diesel engine blocks and heads, Golden is a major supplier to a number of engine manufacturers, including Cummins, Detroit Diesel, Mack and Waukesha.

"Along with our competitive prices, our location is also helpful," said Witt. "Nearly all of the major North American engine manufacturers are within three hours of our location. That's an advantage in today's environment, because it's easier for the customer to get us involved much earlier in the engine design process than before.

"The time to market is cut considerably when the designer, machine tool builder, manufacturing operation, foundry and pattern shop are all able to meet together at any time."

Along with the key-core system, Golden has installed a new Klein sand mixer and Moco drying oven, all of which totaled more than $10 million - " a pretty big bite," noted Witt. In 1999, the company plans to add new shot blast equipment and in the next several years, will invest in new programmable casting cleaning equipment, new automation of the core knockout system and a new charging system for the melting operation.

"These are the kinds of things that allow us to remain competitive with foundries in Mexico and South America," Witt said. "The investments are already paying off.

"The Loramendi system has also helped us improve our quality. Over the last two years, our internal quality has improved 17 percent and quality at our customers has improved 26 percent. Productivity has improved 21 percent and, combined with the Loramendi investment, Golden has been able to offer significant cost reductions to most of its major customers."
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Title Annotation:Golden Casting
Author:Brezonick, Mike
Publication:Diesel Progress North American Edition
Geographic Code:1U3IN
Date:Mar 1, 1999
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