Changing casting demands shape Ford's new foundry.
Ask George Booth, general manager of Casting Operations for Ford Motor Co., wha driving forces are guiding automotive foundries today and his reply is almost instantaneous: "Quality and competitiveness." Just as quickly, he adds, "And government regulations."
All American foundries are confronted with continuous demands to manufacture high-quality, cost-effective cast components. Those specializing in automotive castings have the added pressure of searching out new process technologies and materials that reduce overall car weight to meet federally mandated fuel econom standards while not sacrificing performance.
Each of these elements--quality, competitiveness and government regulations--played central roles in planning Ford's new aluminum facility that opened late last year in Windsor, Ontario.
The company calls the new facility the Windsor Aluminum Plant (WAP), and the highly automated foundry was designed around the Cosworth Process, commonly referred to by the Ford people as the "precision sand process" to produce aluminum engine blocks. For the time being, at least, cylinder heads are also being manufactured using this technique.
Changing Customer Needs
"Our major customer is Ford's Powertrain Operations," explained Booth.
"When I joined Ford 32 years ago, we were producing engines like the 462 cu. in V-8 for the Lincoln. The power density of engines at that time was in the range of 30-35 horsepower per liter. By today's standards, the castings we were producing were pretty low-tech gray iron made in green sand molds with oil sand cores. I remember that hotbox was an innovative new core process then, and cold cure wasn't even an idea."
As he recounted the enormous changes that have occurred in the past three decades, the most significant and positive has been the change in attitude toward customers. "All of us back then were more concerned with mold count than with quality, Booth said. "I can still remember how we argued with our customer saying things like: 'This is a commercial casting; you aren't paying for aircraft quality.' You won't hear us saying that anymore."
The fuel crises of the 1970s and the dawning of age of global competition in th '80s totally reshaped American manufacturing--particularly the automotive industry. Mere survival became the watchword of U.S. businesses.
By the mid-1980s there was even talk of only one or possibly two of the Big Three U.S. automakers surviving. Dramatic changes were in order. "Paradigm shifts" is what Booth calls them. Many of those shifts stretched the imaginatio of the design and casting engineers, and are reflected in the innovative approach Ford has taken in developing the WAP.
Weight reduction without sacrificing power or performance has been the overriding goal at Ford for its powertrains. In 1978, the U.S. Congress mandate that all domestically produced cars would achieve a 27.5 mile per gallon corporate average fuel economy (CAFE). More recently, some have begun pushing for even higher CAFE standards that could range anywhere from 29-32 mpg. To mee these needs, automakers have increasingly turned to lighterweight materials, an castings continue to be a prime target.
"The engines we are producing today," Booth said, "feature four valves per cylinder with overhead camshafts and increasing amounts of aluminum, plastic an powdered metals. Power density, or horsepower per liter, is about double what i was 30 years ago. Weight reduction will continue to be the key to future fuel economy improvements. You will be seeing even more complexly crafted engines constructed of magnesium, ceramics and metal matrix composites."
Cosworth Precision Sand
The Cosworth Process was originally developed in the 1970s to meet the need for highly specialized cast components for the Formula One racing car engines manufactured by Cosworth Engineering, Ltd., in England. Zircon sand molds with furan binder system are filled from the bottom of the mold using an electromagnetic pump.
A vertical launder in the middle of the holding furnace moves the metal at a controlled rate into the rigid sand mold. Locating the fill tube in the middle of the furnace helps ensure that only the cleanest metal enters the mold, thus reducing the possibility of stag or dross entering the mold cavity.
With a blanket of inert gas shrouding the mold metal in the furnace, the molten aluminum is protected from oxygen and other gases that can lead to porosity in the casting. Since the mold fill rate is closely controlled, molten metal turbulence is minimized, also preventing the pickup of oxygen and other gases that can lead to porosity.
Benefits claimed for the process include yields of 85% or better; castings that are 10-12% lighter than those produced by other methods; excellent mechanical and physical properties; and the ability to specify machining allowances in the 1.5-2 mm range.
Why Precision Sand?
Ford's push toward cast aluminum engine blocks and heads is not a new effort. The company has been producing aluminum cylinder heads and pistons for years in its Essex plant, also located in Windsor. What surprised some, though, was the carmaker's choice of the precision sand process for producing high-volume cast aluminum engine blocks. On the other hand, there has been little consensus amon the major auto producers as to the most effective way to cast aluminum engine blocks.
In an article prepared by Booth and published four years ago (see "New Roads fo Automotive Castings," modern casting, October 1990), he pointed out the wide range of approaches to casting aluminum blocks. Cadillac's V-8 block, for example, is diecast and uses slip-in wet liners. A linerless V-8 block produced by Porsche is cast in a hypereutectic alloy by low-pressure permanent molding.
Other examples include Honda's I-4s and V-6 blocks with cast-in bore liners produced in high-pressure diecasting as well as an I-4 model with cast-in liner but produced with medium-pressure diecasting using a sand core to form a closed deck face. Their commonality is that nearly all use metal molds. Ford's Casting Operations, however, took another road.
Ford chose the precision sand process to produce its 2.5 and 3.0 liter V-6 bloc for a host of reasons. Chief among them is that "From my perspective," Booth said, "I don't believe that Ford or any of the Big Three can compete in a matur industry using conventional technology. This is due largely to our labor wage structure. The only way I can compete is if I'm at the leading edge of a new technology's growth curve--to have technology that the low-cost independents don't have."
He explained that the decision to go with precision sand wasn't made quickly or easily. "We benchmarked every aluminum head and block foundry in the world," Booth said. "What we found were the characteristics in the Cosworth Process tha were first class and what we were looking for. For one, because it's 100% sand, there wouldn't be a lot of flash, reducing cleaning and finishing operations. W wouldn't have the expense of metal molds or the costs and other shortcomings of dry sand cores and green sand molds.
"Using zircon sand also offers a lot of advantages, too. Its thermal stability and having the same specific gravity as molten aluminum meant that there wouldn't be any mold wall movement, which reduces distortion of the cores and molds. This results in more uniform wall thicknesses. We felt that once we established the repeatability of the process, we should also be able to reduce the weight of the part. Compared with silica sand, zircon also offers faster cooling."
The Ford benchmark team also liked the idea of using the electromagnetic pump t move the metal from the furnace into the mold, eliminating oxides. The trick wa going to take this well-established, low-volume process and adapt it to high production. When Ford began exploring Cosworth, the company was producing only about 100 blocks a day.
"One of the things we're very good at is to take technologies like Cosworth and develop it into a mass production process," Booth said.
Ford's version of the process uses zircon sand with a cold cure binder. The 2.5 liter block is comprised of 17 cores and the mold for the 3.0 liter version is comprised of 18 cores. Both use cast-in iron bore liners.
According to Buzz Brosnan, WAP manufacturing manager, "The coremaking system wa designed for total flexibility. Each of the 38 machines is identical and can us either horizontally or vertically parted coreboxes. The size of every corebox w use is the same dimensionally regardless of the size of the core being produced and each machine has quick change tooling capabilities."
Nearly the entire core package, including iron liners, is assembled and glued robotically as carriers that hold the core package move down a monorail system. The only manual moldmaking operations are running of the core machine cells (on operator runs two machine cells), and the assembly of several of the smaller cores, according to Mel Rowe, WAP plant manager. Robots remove the cores from the core machines, as well as assemble them into molds for delivery to the pouring operation. They can also be instructed by the machine operator to show core to the operator for visual inspection.
The completed core package is then transported by the monorail system to the melt area, where the cast iron liners are heated to reduce the chilling effect of the iron on the molten aluminum during fill. The package is then transferred to a carousel rollover system that moves it into place for filling.
Unlike the original Cosworth Process where the cavity is filled by low pressure from the bottom of the mold, Ford's automated version fills the mold vertically as the feed tube from the computer-controlled electromagnetic pump is pressed against the gasket on the vertical face of the core assembly. Following the low-pressure fill, the entire assembly is rolled over and away from the furnace The metal in the feed tube then drains back into the 70,000-lb furnace to prevent metal spill.
After mold filling and cooling, trays holding up to six core packages and castings are loaded by robot for transfer into what Ford calls its thermal sand removal (TSR) system. It is essentially a large heat treat furnace with indirec gas-fired tubes. The core assemblies and castings are transported through the furnace on a moving conveyor and are subjected to 932F (500C) temperatures.
During the 4 1/2 hour process, the heat--together with high-volume air--actuall causes the sand to peel away from the castings. The sand then falls down to a conveyor at the bottom of the TSR unit and is fully reusable at this point.
The castings are also thermally treated during the TSR process. This is followe by an air quench, reducing the casting temperature from 932-482F (500-250C) in about 4 1/2 minutes. By the time the castings exit the TSR, their temperature has been lowered to about 86F (30C).
In essence, the TSR unit cleans the castings, reclaims the sand and, according to Booth, "It's metallurgically good for the castings. In some cases, additiona heat treating is needed to reach the T-6 condition. But what the TSR has allowe us to do is eliminate the need for conventional shakeout, decoring and handling operations traditionally associated with mold breakdown and casting removal."
A Green Foundry
The finished castings are then removed from the TSR unit by robot to the machining area, where they are rough milled. This is an area that is particularly pleasing to Brosnan. As part of the team that traveled worldwide t benchmark various casting operations in the late 1980s, he recalls that one of the prime goals of the team was to design a "green" foundry, or one that was as environmentally friendly as possible.
"When it came to the rough milling operations, we knew the biggest problem woul be handling the machining coolants," Brosnan said. "We talked with everyone we could find--machine tool builders, cutting fluid suppliers--about dry machining our castings.
"Talk about paradigms. We were told by nearly every one of them that it couldn' be done. Finally, together with our suppliers, we found a way to rough mill the parts without cutting fluids."
This thinking was carried through during the entire development phase of the WAP.
"The only thing we wanted coming out of this plant," Booth said, "was the finished product. We didn't want to have to dispose of any water or any sand. Right now, we're getting about a 1.5% sand loss, mostly in fines from the sand reclaim system. We take those fines and sell them to a company that can use the in their operation. The cold cured resin is burned off in the TSR unit and any residual material from the coremaking process is returned to our supplier, who re-processes it."
Even before the first metal was poured at WAP on August 17, 1992, plans were under way to expand Ford's aluminum casting capacity.
"The engine blocks we are producing at WAP now will go into our new world cars--the Contour and Mystique models--that are coming out this fall," Booth said. "You will see more and more aluminum heads and blocks in Ford cars betwee now and 2000, and we will have the capability to meet all of Ford's requirements."
When WAP is running at full capacity, its annual volume of engine blocks is expected to exceed one million units. Some aluminum cylinder heads are also being produced at WAP to support Ford's current engine program.
But a major expansion is under way at the company's Essex aluminum plant in Windsor. Booth expects that within two years WAP will be producing only blocks with the cylinder heads made at the Essex plant using gravity and low-pressure permanent molding. Essex will also continue producing cast aluminum pistons.
"We came to the conclusion a long time ago," Booth said, "that the core of our business was going to be cast heads and blocks in iron and aluminum, and forged and cast crankshafts. In fact, we're building a new steel forging plant. We are continually looking at other parts, processes and materials like compacted graphite iron and metal matrix composites."
And what about the precision sand technology? Is there any fear that as Ford develops it and demonstrates its viability that others will try to adopt it as well?
"No," Booth said. "In 1988 we signed a 10-year, worldwide licensing agreement with Cosworth that allows us exclusively to manufacture motor blocks and heads in high volume. That means that no one other than Ford can use the process to produce more than 30,000 engine sets a year.
"We've spent six years developing the process and when the license comes due in 1998, we'll decide then whether to renew the agreement. So, no, we're really no too concerned about someone else taking advantage of our developments."
You really can't help but pick up on the excitement the Ford team feels when talking about the new Windsor Aluminum Plant. Besides Booth, Rowe and Brosnan, Bill Landers, John Bogatay and Don Penrod are part of a very large team to credit for the development and design of the new facility.
"I'm very proud with the way the plant has evolved," said Booth. "Not only with the technology, but also with the human resource team that we have there. The development team members participated in all major decisions, starting with the statement of the plant's guiding principles. In fact, it's difficult to tell who's management and who's hourly.
"With the upfront effort that we put into the plant in terms of ergonomics and making it a good place to work, we believe that we have a 21st-century casting facility--not only in terms of technology but in our human resources as well."
WAP Started with CARD
While the initial objective was achieved when the first metal was poured at Ford's new Windsor Aluminum Plant in August 1992, the Cosworth precision sand process for high-volume production of aluminum heads and blocks had been given "feasibility test drive."
That process started four years earlier on August 17, 1988, the day that ground was broken for the company's CARD (Cast Aluminum Research and Development) facility. Construction of the $6 million plant reflected the urgency that Ford' Casting Operations was feeling to develop the new technology and materials that its customers needed.
"The thing I remember most about getting the CARD facility off the ground," Booth recalls, "is that we went from a cornfield in Windsor to building occupancy in 90 days. I'm talking about permits, sewer, water, electricity--the whole nine yards. And we were up and running within a few months after we moved in."
The CARD facility, located adjacent to WAP, was developed and designed to use full production size equipment. According to Don Penrod, who heads up the plant "We decided that we would only use equipment that would be used if we decided t go into full production. We didn't have the time to work with prototype or laboratory type machines." The results of the initial work done at CARD can be seen at the Windsor Aluminum Plant.
Recently, the CARD team completed a project involving low-pressure cylinder heads and various other work for Ford's other casting operations, including their iron foundries. "They've got a lot going on there," Booth said. "Their jo is to make our existing business more competitive."
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|Title Annotation:||includes related article; Ford Motor Co.'s Windsor Aluminum Plant, Windsor, Ontario|
|Author:||Kanicki, David P.|
|Article Type:||Cover Story|
|Date:||Sep 1, 1994|
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