Lost Foam Casting.

"Creativity is allowing your self to make mistakes. Art is knowing which ones to keep. --Scott Adams

For the casting world, it is a good thing art founders "kept" working on the little process they stumbled upon in the 1950s. They found that sculpted polystyrene patterns could be placed in sand molds and volatilized by the molten metal to take the exact shape of their creations. While the process received almost no attention from commercial foundries in its early years, art casters plowed through some of the early technical challenges that eventually brought to light what the process could do for the rest of the foundry world.

The process' contributions were no small feats. Today's lost foam process offers: reduced/eliminated machining, weight-reduction via zero draft, improved casting accuracy, complex internal coring of passages, extended tool life and high design flexibility that allowed component integration or other features that were difficult or impossible in conventional casting. Plus, this environmentally friendly alternative did all this without binders, cores, sand preparation and other foundry operations.

It also helped demonstrate the advantages of marketing to an industry that largely waited for the phone to ring. The process was so new and so different that it required foundries to take a role in application development. Said Rickey Robinson of Robinson Foundry: "It forced us to get more intimate with customers so we could know what they were after. We'd say, 'Don't pay any attention how we'll get there, just tell us what you want to end up with.' We'd throw out the absurd, but we found that foam could do a lot of things. We had to push their thinking and get away from everything we know about the conventional foundry business."

Truly an 'Art'

Artists, not necessarily known as technological scientists of the casting process, did indeed set the ball rolling for today's lost foam process. MIT Professor Mert Flemings prepared (along with Alfred Duca and Howard Taylor) what is believed to be the first paper published on lost foam at the '62 AFS Casting Congress in Detroit. In his paper, which illustrated 17 art castings, Flemings wrote: "An artist named Alfred Duca called to tell us about a 'foam vaporization process' he had developed and to see if it had any commercial applications."

Duca had been carving simple patterns and gating systems out of expanded polystyrene and placed them in green sand molds. He learned that as the metal entered the cavity, it would completely replace the foam, "faithfully reproducing the detail of the pattern."

"I went over to see it and was astonished," said Flemings. "We couldn't find anyone interested in commercial applications for it, but the Ford and Rockefeller Foundations supported us for developing it for art castings."

A patent for the process was granted to Harold Shroyer in '58, and the use of loose, unbonded sand (lost foam by today's definition) for the process began a few years later. In his '87 AFS Silver Anniversary Paper, Flemings wrote: "During the late '70s and into the early '80s, driven by the need for weight and cost reduction, interest in the process by automotive foundries increased dramatically."

Robinson Foundry

The first North American jobbing foundry to make a significant entry into lost foam was Robinson Foundry, Alexander City, Alabama. "We were facing a lot of offshore competition and had to find a better way," said Joe Robinson, recalling the impetus for entering lost foam.

While Robinson first achieved prototype success with electric motor housings, the first commercial shipment was a ductile iron exhaust elbow for Mercury Marine. "The only way to prove lost foam was to get tooling, but you couldn't get that without big money," said Rickey Robinson, talking about the early hurdles. "We took any foam we could get our hands on. There is so much known today about foam densities, glues, coatings and foam control--we were successful at a time when we didn't know whether or not we were doing things right. Anyone who tells you the process can't stand much variability didn't see our operation and the success we had."

Bruce McMellon, Vulcan Engineering, said that the Robinson brothers' entry was significant not only because it was the first iron jobbing foundry, but also because they did it without a customer or market in hand. "They created a whole new look to the process, creating an appeal beyond automotive."

Many also credit Robinson with furthering knowledge about the process among both foundries and users. "They knew they needed competitors to be successful and could grow lost foam if others got into it and established credibility," said McMellon. "That was as important as the actual work they did on castings."

Added Steel Founders' Society of America's Raymond Monroe, who was involved in the building of Saturn and wrote the first comprehensive lost foam book: "The fact that these two boys from Alabama could sell the technology with commercial success--particularly on parts that couldn't be cast in any other way--opened a lot of eyes." They also consulted other foundries on everything they knew about foam and prepared what was likely the first "how to" manual on the process.

In addition, the Robinsons also had much to do with the launching of the dedicated lost foam equipment lineage in the U.S. In the mid-'80s, during a scotch-sipping session, Joe Robinson and Vulcan's Phil Zettler designed the first jobbing line on the paper sack in which the bottle was sold. That first line was a hook-style overhead system in which workers pushed flasks around manually.

One of the more memorable moments in lost foam history involved the Robinsons during an early AFS Lost Foam Conference. Unbeknownst to the conference planners, the dinner speaker declared (based on some limited experiments in Europe with technology lagging behind that in the U.S.) that producing iron via the process just was not possible. Many recall Rickey Robinson jumping from his seat and yelling, along with a few expletives, that "I better call the foundry and tell them to stop shipping those 50 tons of castings per day!"

The lost foam family tree of two of the larger U.S. foundry groups' entry into larger-scale lost foam production is also traced to Robinson. Its iron business was eventually sold to Citation Foam; and its Bodine-Robinson joint-venture was sold to Internet.

General Motors & Saturn

The most significant proponents of the process have been and continue to be General Motors and its Saturn subsidiary. GM began early development workshortly after news of the invention in Warren, Michigan. Vulcan Engineering's Parker Stroom, who took an instrumental role at Saturn, first saw the process at the GM Tech Center in the mid-'70s when he was with Central Foundry. "The first time I saw it, the researchers were embedding the foams in steel shot," he said of the early experimentation. Later that decade, GM commissioned a study at its Massena, New York facility, and in '81, the plant started its first large-scale lost foam production of aluminum cylinder heads for the 4.3 L, V6 automotive diesel engine. While short-lived, the experience paved the way for the 2.0L inline four-cylinder head in '86.

The biggest shot in the arm came with GM's plans for a new car company, Saturn, in the mid-'80s. "There was a strategic decision in '85 to look at lost foam for the block," said Stroom, who wassent to Spring Hill, Tennessee, to ramp up the foundry. "As more product people came to the table, lost foam began to look so good on paper that all of a sudden, we were looking at a number of parts." With the full-on commitment to lost foam in '86, the fate of the startup company relied heavily on the process for 100% of its aluminum engine blocks and cylinder heads, and all of its ductile iron crankshafts and differential cases.

"We knew the magnitude of risk and it was decided to go in without a safety net--foam had to succeed," said Stroom. "The industry thought we were crazier than hell." A 20,000-sq-ft Casting Production Readiness Center opened in Southfield, Michigan in '87 to validate the process and training.

History has shown that the decision paid off. Lost foam is considered to be among the greatest successes in the automaker's short history. To put into perspective the benefits seen, on the block and head machining lines alone, more than 16 ft of drilled holes were avoided by using as-cast passages not attainable in other processes. In other words, for each engine, more than 20 cu in. of aluminum that would have been generated in chips was avoided, yielding significant reductions in capital equipment, variable operating costs and aluminum costs.

Clearing the Hurdles

Lost foam has not been without its share of problems: technically, politically and in customer acceptance. It faced competitive resistance within the industry, and some foundries toyed with it only enough to "prove" that it couldn't work. On the other hand, recalled Stroom, "you also had pseudo-experts that climbed on the bandwagon and oversold its capabilities. It's manageable and controllable but needs its own set of rules and its own design."

An important step toward solving the process' unique technical issues occurred when a Lost Foam Casting Consortium of casting producers, users and suppliers was formed with the Dept. of Energy in '89 to share insight into the process and further develop the technology. To date, research has focused on precision foam production, coating consistency, sand fill/compaction and casting precision. New instruments for reducing scrap and improving casting precision were released commercially through the consortium's efforts.

The Present

Other early adopters of lost foam still in operation today include Citation Foam (originally Simsco), Willard Industries, Advanced Cast Products, Mercury Marine and OMC. Today, there are about 25 lost foam-dedicated foundries in North America, including several recent entrants among the captive, production and jobbing scenes alike.

The process' environmental performance also has resulted in greater attention today. "The lost foam process is undoubtedly the most environmentally friendly operation of our time," said Saturn's Jim Deppler, noting the impact of no sand binders and near-100% sand recovery. "Solid, liquid and gaseous wastes approach the zero-emission category."

The outlook for lost foam applications remains bullish--and the most favorable of all sand casting processes. According to Stratecasts Inc., demand for castings produced via lost foam and variations of the process could more than double between now and 2008, reaching 450,000 tons.

When asked about the net difference lost foam has brought to the metalcasting world, Monroe said, "A lot of today's lost foam parts were previously made from bar-stock, forgings and fabricated weldments. In addition, it created a whole new excitement and interest in cast metals."

Other Early Lost Foam Contributors

Some of other early contributors to lost foam's development include:

George Vingas--Credited with the hard-fought battle of making lost foam a separate AFS division (it had been a subcommittee within the molding division). Influential in developing coatings for the process. Found and secured Dept. of Commerce research funding.

Al Bryant and Gary Bishop, GM Tech Center--Directed most of GM's early process development.

Russ Van Rens, OMC, and Ray Donahue, Mercury Marine--Each believed in the process early on and propelled its development for marine engines. Said one industry official, "Donahue continues to be the most biggest champion of the process."

Karel Cermak, Styrologic/Vulcan--Provided early expertise on bead preparation and foam-molding for the process.

Norm Lilleybeck, John Deere--Vingas credits Lilleybeck for the first push of momentum for the Lost Foam Div. "He started opening up when everyone was keeping the secrets to themselves," he said. He also was credited with bringing new mathematics into the discussion.