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EPC producer-user conference examines latest achievements.

Expendable Pattern Casting (EPC) has been consistently gaining credibility within the foundry industry as a viable casting process. But the ultimate success of EPC will be determined through its acceptance by casting users and design engineers.

A recent AFS International EPC Conference held in Rosemont Illinois offered the opportunity to discuss the latest achievements with users and designers. A mini exhibit allowed attendees to meet the suppliers and equipment manufacturers who are the leaders in EPC casting development and casting production.

Twenty-nine presentations were made to over 100 attendees (from the U.S., Australia, France, Brazil, Germany, Canada, Singapore and England) on a wide variety of topics.

Success at Saturn

Parker Stroom, Saturn Corp., the conference keynote speaker, addressed the success of EPC production at Saturn. Six EPC components are being produced: an aluminum engine block, two cylinder heads in aluminum and ductile iron, a crankshaft, and two designs of the differential transmission case.

Of the many reasons for choosing EPC over conventional casting methods were the near-net-shape, as-cast details, greater design flexibility, combined components cast into fewer parts, reduction in machining and assembly operations.

The floor level get the job done" attitude served as a benchmark in corporate resource commitment and support. The foundation of the Saturn people system is the work unit. A self directed, multi-disciplined team of approximately 10 to 18 members. A single work unit produces and is responsible for one part family from EPS beads to finished casting. The design stimulates team building and job enrichment.

With today's focus on environmental concerns, Thomas Bohnert, Dow Chemical Co., discussed a new polymethylmethacrylate (PMMA) expendable resin containing a hydrocarbon blowing agent to replace chloroflourocarbon. The new formulation was developed to abide with the Montreal Protocol dealing with ozone depleting substances in response to customer feedback.

Foundry evaluations worldwide showed that the use of this new resin results in significant reduction of problems related to lustrous carbon defects. Compared with original PMMA resin, the new resin provides the added advantage of shorter total molding cycle times. The performance characteristics of the new material include a slightly longer pre-expansion time at lower densities, equivalent moldability, shorter mold cooling time similar dimensional shrinkage, equivalent strength and similar castability.

Users Evaluation

The users evaluation session provided insight into the growing credibility of EPC. Tom Betchen, John Deere Dubuque Works, discussed experiences and expectations at Deere. Some of the applications that were evaluated were steering drums, flywheel housings and oil filter adapters. The steering drum, being the most successful EPC application to date, was machined directly from EPC for prototype work to eliminate the high cost of prototypes for the initial evaluation. The flywheel housings were previously machined on a multi-spindle machine the machining savings were not as remarkable as other applications.

Another bucket tooth application successfully made EPC prototypes with a comparable piece price, but the tooling was more costly than the shell core method currently in use. Since the EPC method is not a cure-all for all problem casting applications, companies must take an educated look at what they are tying to accomplish before jumping into new applications.

Some of the advantages that Betchen sited were cost-competitiveness on medium-to-high volume parts with conventional casting methods, machining savings and rapid prototyping (from machined EPC). On the other hand, high tooling and prototyping costs (with molded prototypes) along with lengthy development times were considered detrimental to the process.

Michael Allegrucci, Bendix HVS, discussed the conversion of conventional green sand cast applications to the EPC process. Green sand applications were machined and assembled as regular production parts. For the EPC castings, some cast-in features were added. Both groups were poured from the same base iron alloy. The EPC test castings were found to have a higher level of silicon than was desirable.

Jim Olgilvy, U.S. Army, Tank-automotive Command, feels that there are many cast armor areas that are perfect for EPC. The Army eventually hopes to supply 1100-1400 vehicles with EPC ballistic castings.

European Interest

Dr. Laurent Marais, Saplest, France, presented the status of EPC opportunities and new developments in Germany after unsuccessful attempts with EPC in the early'80s. Besides Italy and France where a few more foundries are active, now countries such as England, Sweden, Spain and Switzerland are also joining the EPC world.

During the last few years, EPC has been developed and used as a production process mainly in italy at Teskid and in France at Peugeot and Citroen. More recently, several more independent foundries or those belonging to automotive companies have been developing the EPC method for their own use. Applications include: diesel engine blocks, brake discs, engine supports, electrical railway components, and the heating and piping industry. One of the main advantages seen in these new applications is the increase in design possibilities and less weight and machining costs.

Future of EPC

Raymond Monroe, Steel Founders' Society of America, summed up many of the opportunities that are available for future EPC castings during his dinner presentation. "New technology creates new opportunities, and this is clearly true of the EPC process," Monroe began. The casting user reaps many rewards with EPC: greater design flexibility, good dimensional capability and possible part consolidation. Before the full benefits of EPC are available, several hurdles need to be overcome or at least lowered significantly.' They include: process complexity, development of tooling, production of prototype castings and the development of new markets.

The EPC process requires teamwork between the casting producer, part designer, patternmaker and statistical analyst. Few of the opportunities of EPC will be realized without a systematic statistical approach that uses all the available experts to design and interpret new developments.

Cooperative research is another essential ingredient to success. An AFS/ Department of Energy project shows the benefits of this type of approach. No one company or organization has the expertise to move the process forward quickly. This type of project allows all the major players to share the costs and risks of new developments.

Successful companies will differentiate themselves by creative and aggressive implementation of research results. The most significant opportunities lie in market development. The only way to efficiently and profitably expand the use of EPC is to better meet customer needs.

A conference sponsored by the Society of Manufacturing Engineers (SME) in cooperation with AFS, Designing EPC Castings' will be held November 6-7, 1991 in Nashville, Tennessee. For information, call 313/271-1500.
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Title Annotation:AFS international conference; Expendable Pattern Casting
Author:Thomas, Susan P.
Publication:Modern Casting
Date:Oct 1, 1991
Previous Article:Foundries alerted to new environmental regulations.
Next Article:Common goals! AFS chapter leaders exchange ideas.

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