New roads for automotive castings.
* and the integration of components to reduce engine system complexity.
Innovations in processing have been Casting Div's objective for meeting changing customer wants. For example, a four-cylinder block introduced in the 1980 Escort employs a core assembly concept that was developed to improve dimensional control and reduce casting scrap.
For the block, the one piece crankcase core, journal slab core, waterjacket core and head-face slab core have interlocking prints to ensure an accurately locating one core to another. These cores are assembled in the coremaking area, secured by banding and delivered as a rigid package for setting into the drag mold. This technique improves the core-to-core fit and reduces core handling damage compared to that caused by loading individual cores into preset fixtures at the molding line. A 3.OL 601 V-6 block, introduced in 1985, employs a core package concept that was specifically developed to meet significantly improved quality objectives. All cast surfaces of the block, except the valley, are formed by cores. A total of 10 cores are used, including cores to form the sidewalls. Once assembled the interlocking cores are secured with tie bolts to form a rigid package for direct delivery to the molding line. Looking to the future, a new V-8 block planned for the early 90s required further innovation because of added product features and greater dimensional consistency to meet more demanding requirements. These features include: * full-length head-bolt bosses to improve cylinder bore roundness during engine operation; * a deep skirt to increase powertrain rigidity and improve oil pan sealing; * compact cylinder bore spacing to reduce engine length; * large oil drain bosses to accommodate increased oil flow from the overhead camshafts; * an integral water-pump housing and inlet passage which improves coolant system integrity, reduces engine complexity and shortens engine length; *o and a front cover flange to partially enclose the camshaft chains. The impact that product features like these have on the foundry can best be explained by looking at the water jacket core. First, the requirement for a compact bore spacing dictates a minimum sand section between bores. Next, the bosses for the full-length head bolts wipe out much of the sand section holding the jacket together. The bosses also prevent placing the core supports in the optimum location between the bores.
Finally, these head bolt bosses and the oil drain hole bosses induce additional heat load to the less robust water jacket core. These features do not make it any easier to improve cylinder bore wall uniformity or reduce water jacket wall thickness. To provide product features like these, while at the same time improving cylinder bore wall uniformity and reducing waterjacket wall thickness, requires new and better approaches such as an innovative 13 core assembly that forms 90% of the surface area of the casting.
The assembly starts with four individual crankcase/barrel cores and both and cores. These six cores are set into a fixture which is then located into the core machine. A key core is then blown into a channel on the underside of these cores, effectively creating a one piece monolithic structure. In addition to accurate and rigid location of these six cores, the keyed assembly provides the foundation for installing the side cores, water jacket cores, water pump core and water inlet core. Aluminum Blocks
Aluminum is receiving renewed interest for cylinder block applications in the U.S. because of federally mandated fuel economy standards. The V-8 iron block described above would weigh 80 lb less if it were aluminum. Couple this with an additional 112 lb vehicle weight savings for every pound of engine weight reduced and a substantial 120 lb vehicle weight reduction opportunity results.
A dilemma facing both the product designer and casting supplier is that there is no consensus on key product features or the best casting process for aluminum cylinder blocks. The wide variety of process, material, design and product feature choices are graphically illustrated on the following page.
A good example of how quickly key product features and casting process is a V-8 block produced by General Motors in the 1960s that featured cast-in borelinersandacloseddeckface.Over 750,000 blocks were produced by gravity semi-permanent molding. When the block machining line was sold to a company in the United Kingdom, this block was then produced as a sand casting and the liners were pressed in place.
Product feature options for aluminum cylinder blocks include dry liner, wet liner, linerless, press-in liner, cast-in liner, open deck and closed deck. These options in conjunction with the various casting processes available gives the designer a large number of possible combinations.
At the same time, casting process options for producing blocks include high-pressure diecasting, low-pressure permanent and semi-permanent molding, gravity semi-permanent molding, sandcasting and EPC. It should be apparent that there is a close relationship between design and process; between designer and casting producer.
The Ford Casting Div believes that a precision sand process coupled with nonturbulent metal filling is the best approach to achieving these wants at high quality, lowcost levels. An aluminum version of the previously discussed iron V-8 block, produced in this manner, for example, would include a number of value-added features not found in the iron block. These are cast-in oil pressure and drain holes and a reduced number of core supports. Cylinder Heads
Customer wants for aluminum cylinder heads are the result of the move toward high output, four-valve per cylinder designs having multiple camshafts. These wants include:
* improved metallurgy and casting soundness, more accurate and consistent port and combustion chamber shapes;
* more complex and intricate water jackets;
* reduced cost;
and the integration of valve train/ camshaft support structure.
* The shift to aluminum and four-valves per cylinder in North America has lagged behind that of Europe and Japan. in North America the shift from iron to aluminum began around 1980. Ford's first aluminum cylinder head was an overhead camshaft two-valve design for the Escort. Ford, Chrysler and the majority of GM's heads are produced by gravity semi-permanent mold and, except for the Oldsmobile Quad Four, all are twovalve designs. GM is producing one type of cylinder head by the EPC process today and is planning to produce the Saturn two-and four-valve cylinder heads by this process. In response to this shift to aluminum, Teksid and Montupet, have both built foundries in North America.
Japan uses both low-pressure and gravity semi-permanent molding but there appears to be a preference for low pressure. Japan has employed aluminum heads exclusively for many years and last year they produced 1.7 million four-valve heads.
European aluminum head usage dates back many years and is running at about 90%. European practice is largely gravity semi-permanent mold. Some 250,000 four-valve heads were produced in 1987. Montupet and Nissan are both setting upfacilities in the U.K. to produce aluminum heads.
Casting Div believes that a precision sand casting process with controlled mold filling, as described for aluminum blocks, has the capability of providing the required quality and soundness levels with greater value-added features, and at a lower cost than other processes.
In cylinder leads, there is also customer interest in the elimination of or casting in of valve seat and guide inserts. There is also interest in cast-in ceramic port liners such as in the Porsche head, to reduce exhaust gas temperature loss. intake Manifolds
intake manifolds play an important role in meeting engine performance objectives. With the advent of fuel injection, product engineers are now designing manifolds that have long, equal length runners and air plenums. Runner lengths which can reach 13-20 in. are determined by vehicle performance objectives. Customer wants for the intake manifold are: 9 compactness, o lightweight,
low cost, 9 and appearance.
Aluminum intake manifolds have been produced by various processes over the past 20 years. One of Casting Div's earliest was a one-piece high-pressure diecasting. This manifold was in production for several years. It was eventually replaced by a semi-permanent mold casting because of the more efficient runner passages obtainable from sand cores.
A two piece high-pressure diecasting was in production for several years on early 3.8L V-6 engines. Electron beam welding was used to join the two die castings. Pressed-in steel tubes were used to circulate exhaust gas and a stamped plate was used to cover a water crossover passage. This manifold was eventually replaced by a semipermanent mold casting because of added product complexity. The semipermanent mold casting has since been replaced by a two-manifold system produced by the EPC process as product requirements became more demanding. Ford and GM have started to use fabricated manifolds made by combining aluminum tubes and aluminum castings. The primary attraction is light weight although there is belief that air flow improves because of the smoother surfaces.
Composite or plastic intake manifolds are also showing up. Ford of Europe's 1.8L 1-4 Diesel now uses a thermoset phenolic manifold. The primary attraction is light weight, but the near net shape capability of the injection molding process eliminates most machining operations. Ironically the thermoset manifold relies on a metal casting to form the internal passages. This low-melting temperature alloy is melted out of the manifold using hot oil and is recycled.
In 1983 Casting Div began producing intake manifolds by the EPC process. We believe that this casting process, with its capability to provide greater design flexibility, will compete effectively with other processes and materials for the manifolds of the future.
Ford's new modular V-8 intake manifold system is a case in point. Engine performance objectives dictated long runners and a large plenum, Other passages were also required to be cast for water and exhaust gas. Manifold requirements like this have been met in the past by employing separate upper and lower castings bolted together. But the compact spacing of the runner passages left no room for attaching bolts to join separate upper and lower castings. This necessitated a one-piece casting, which is a formidable task for most casting processes. The one-piece casting reduces weight and cost, and by eliminating a gasketed joint, improves system reliability. Crankshafts
Engine designers consider the crankshaft to be the backbone of the engine. Higher specific output, coupled with higher revving engines are placing a greater load on the crankshaft at a time when it is being downsized to reduce friction. Customer wants for the crankshaft include: * higher fatigue strength, * stiffness, * dimensional, * and metallurgical consistency.
An important issue facing the casting supplier will be the tendency of the engine designer to select a forging rather than a casting for these new crankshafts. Japan now used more forged steel than ductile iron for crankshafts about 60% versus 40%-primarily as they go to higher speed four-valve engines. Ford's understanding is that in Europe the ratio is about 20% forged and 80% cast.
At Casting Div crankshafts are produced in green sand and by shell molding. The plan to meet customer wants for future crankshafts is to use shell molding exclusively because of: improved dimensional control; less finish stock on machined surfaces; less end-to-end hardness variation; and the shell process is less prone to carbon flotation on bearing surfaces.
The challenge to the casting supplier is to produce the highest quality, highest strength and lightest weight crankshaft at the lowest cost. Hopefully, this combination will greatly reduce the possibility of the engine designer justifying the cost penalty of the forging. Exhaust Manifolds
Customer wants for exhaust manifolds include: * reduced weight, * reduced cost, * and good thermal fatigue properties.
Lighter weight manifolds, in addition to reducing vehicle weight, have less thermal inertia. This allows the exhaust catalyst to light off more quickly after engine start up, and is an effective means of reducing emissions. The challenge to the casting supplier is to provide a lightweight alternative to stamped or tubular steel weldments. Experience has shown that the weight reduction of these steel components comes at a substantial cost penalty.
Cadillac is using 3.2 mm wall thickness ductile iron manifolds supplied by a French foundry using a pressure-fill shell molding process. At Casting Div exhaust manifolds are produced in gray iron at 5.0-6.0 mm walls in green sand. The Division is also producing them in ductile iron with 3.5 mm walls at its New River joint-venture with intermet, using vertical flaskless molding. The ability to provide a 3.0-3.5 mm wall casting having good thermal properties at a low cost will ensure that this component does not become a steel product. For this project it is imperative that the caster work closely with the customer to achieve a design that is inherently efficient in material usage. Camshafts
Camshaft customer wants are: * low cost, * light weight, * and high contact stress capability.
Camshafts are another component undergoing change, mostly due to the move to lower friction roller follower valve trains and higher engine rpms. This change in product design and operating environment has required the engine designer to look at newer materials and processes capable of higher contact stresses. Some of these being used today or under development are hardenable iron, chilled iron, machined steel billets, forged steel, ductile iron, austempered ductile iron fabricated with powdered metal lobes and hollow investment cast steel. The incentive to do this is much greater now that the trend is to multiple camshafts for each engine. Casting Div presently produces camshafts in hardenable alloy iron using green sand molding. A fabricated camshaft consisting of powdered metal lobes on a hollow steel shaft is presently in production on one Ford engine, with future applications planned.
Hollow investment cast camshafts have also been under development. The primary advantages are reduced weight and higher contact stress capability. GM has a technology licensing agreement to develop a vacuum process for thin-walled components. At the present time, however, GM cams are produced conventionally in ductile iron, hardenable iron and machined steel billets.
Much of what has been discussed here has been aimed at delineating the direct customer wants-the automotive designer's technical demands on the foundry industry in the 90s. Just as important, I hope you your imagination has been piqued and you are entertaining ideas on how best to approach these challenges. Now, let's take a closer and somewhat pragmatic view of how the increasing demands of the customer will affect the way we do business in the years ahead. Business in the'90s
As we begin the 1990s, the very nature of how foundries conduct their business will change dramatically. Changes will touch all areas of your business from the organizational structure to manufacturing facilities as well as the product itself. Quality excellence will be expected in all areas of a business from the design of a casting to followup at the customer's plant. Implementation of advanced technologies in foundries will accelerate to an extent never before seen in the industry.
Since virtually every step in a manufacturing process can affect total production economics and timing, and these steps are all highly influenced by the basic design;a much closer working relationship must be established between the design and manufacturing functions at the customer and the foundry. This link must be established in the very early design stages. As a supplier we must understand our customer's needs, and as the customer we must understand our supplier's capability to provide the products and services we desire.
To answer the challenges of the future we will have to provide much more than just a technical solution, although the technological innovations are an important part of the answer. The more important challenge is the how" of the task: how we approach the technical challenge, how we broker resources to accomplish the task, how we ensure that the solutions are implemented on a timely basis. Too often the "what" is accomplished with little regard for the how. "The technical challenges we face are obvious, they are the "what" of the challenge, but what is more important is the manner in which we answerthe how" of each challenge.
I believe that we should give some careful thought as to how we can help each other cope with what is waiting for us up ahead. We must learn to work as a team in the future and discard the notion that one person has all the ideas. We must learn to listen and come to a consensus. I believe we will be able to meet these challenges if we focus more on the human side of our industry which is its life-blood.
Donald Petersen, Ford's former chairman, said in a 1982 speech that people are our second bottom line. He said, "certainly we will still be measured by how well we handle our financial bottom line, but in addition we will now also be measured by how well we handle our human resources".
We have to meet the human challenge head on. How do you as a supplier and customer plan to go about meeting this challenge? How are you going to manage your human resources to accomplish the technical challenges? As a supplier, how are you going to interact with your customer? At arm's length or as a member of a team? To answer these challenges will require, for the most part, a cultural change for us-a change in our work ethic philosophy . It won't be an easy task, but it certainly is a doable task. it is a task that we must begin now and incorporate as part of our way of doing business every day if we are to survive.
Will you be up to the task ahead? The challenges of this decade are immense, but so are the opportunities. Your attitude will be critical. Do you see the 1990s as a problem? Or as an opportunity? More than a century ago, the revered Russian writer, Feodor Dostoevski, said: Neither man nor nation can exist without a sublime idea. " One such idea is to stop looking at things as problems and see things as opportunities. The Japanese "Kaizan" philosophy views problems as mountains of opportunities.
I believe that our foundry industry in partnership with our customers will meet these opportunities and the challenges they produce head on. We will arrive at innovative, profitable solutions, and together we will survive. We cannot be content to just say that we've already started to do this if we don't have a strong sense of urgency to carry through with it. Will Rogers said, "Even if you're on the right track, you'll get run over if you just sit there.
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|Title Annotation:||metal castings for the automobile industry are being produced with new processes and materials|
|Author:||Booth, George N.|
|Article Type:||Cover Story|
|Date:||Oct 1, 1990|
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