Mercury castings: this firm's 2001 introduction of the pressurized lost foam process set a new standard for production casting. Here is an update on the foundary's progress since our May 2001 cover story.

In our May 2001 issue, MODERN CASTING unveiled the pressurized lost foam casting process the Mercury Castings Div. of Mercury Manne, Fond du Lac, Wisconsin, had installed for the production of captive and commercial engine components (see "'Core Competency' Includes Lost Foam at Mercury Marine," MODERN CASTING, May 2001). Fifteen months later, we name Mercury Castings MODERN CASTING's 2002 Foundry of the Year.

Based on the recipient of the 2002 AFS Plant Engineering Award [which is awarded by the AFS Plant Engineering Committee (1-D)], the Second Annual MODERN CASTING Foundry of the Year Award is bestowed upon Mercury Castings for its innovative, first-in-North America casting process. This article provides an update of where this foundry stands today, a little more than one year after turning up the pressure on the global lost foam casting community.

A History Recap

In 1985, Mercury Castings built a R&D lost foam casting line capable of 12 flasks/hr to produce aluminum engine blocks and cylinder heads for its parent corporation's (Mercury Marine) inboard and outboard marine engines. The goal was to determine the feasibility of the lost foam process for full-scale production. Over 15 years of production, this line grew to account for 15% of the firm's overall casting production.

While Mercury Castings developed proficiency in the design and manufacture of complex small engine components in lost foam, the foundry was presented with a new challenge in 2000 when Mercury Marine started to design a new 6-cylinder engine. Based on the success Mercury Marine's engineers had with designing its three-cylinder block and head in lost foam, the firm targeted the 6-cylinder for the process.

By designing for lost foam, this engine design (Fig. 1) could accomodate hollow sections that couldn't be cored-out in diecasting or semi-permanent mold (the processes used for its previous 6-clinder blocks). In addition, Mercury wanted the ability to produce this block and head integration with its newest alloy development, B391, a high corrosion-resistant aluminum alloy with increased wear resistance.

The dilemma was that this new component would tax the capacity and quality limits of Mercury's existing lost foam line. This was coupled with the fact that Mercury had determined its skill in the design and manufacture of complex lost foam components was in demand and could open the door to commercial casting jobs.

"OEMs are looking for lost foam casters with our skill in design and casting of complex small engine components," said Dave Dickirson, director of Mercury Castings. "There is a niche that needed to be filled, and we had already developed the expertise to do it,"

With the new 6-cylinder engine on the horizon and a desire to solicit commercial business, a new lost foam facility capable of higher production volumes was required. The result is a 20,000-sq-ft lost foam casting plant that began its first production run in May 2001, The $10.7 million facility has a single lost foam line operating at 24 flasks/hr, and is projected to produce up to 15 million lb of castings.

A Production Recap

This lost foam line is state-of-the-art technology, according to Dickirson, centered around the first North American installation of the French firm Pechiney's Castyral Process for pressurized lost foam casting. This process, which applies 10 ATMs of pressure during casting solidification, provides Mercury Castings with three advantages for its components:

* reduced porosity to near undetectable levels;

* increased elongation properties;

* increased fatigue life.

In the past, the potential use of this pressurized process had never been fully realized by other lost foam casters due to the copper content of the alloys being cast. Due to this, Mercury Marine only uses copper-free aluminum-silicon alloys (such as 356 and 391) as they have high corrosion resistance and an unique feeding response to modest applied pressure.

During pressurized lost foam casting at Mercury Marine, the flask is lifted from the foam molding line by a gantry (after being filled with the gated foam pattern and molding media) and placed in one of six pressure vessels (Fig. 2). The robotic arm then pours the metal, the lid on the pressure vessel is closed and 150 psi of pressure is exerted on the casting for approximately 15 mm as it solidifies. After the prescribed cycle time, the flask is removed from the vessel and placed back on the line for automatic extraction, quench and finishing. Both conventional and pressurized production can be run on the same line.

Current Status Report

The only major changes to the lost foam production system in the last 15 months include the addition of an oxidizer to control polystyrene emissions, additional process control devices and additional measures for noise control. The firm also is planning to add a second compaction table to the molding line to eliminate a current bottleneck. In addition, the "white side' (foam pattern production) for Mercury is now being outsourced to two different firms (only one previously), one of which is a local polystyrene manufacturer Mercury has teamed up with to teach the art of lost foam pattern production.

Currently, the new casting line is at 50% capacity. However, based on projections and components in qualification, Mercury projects the new foundry will be at 80% capacity in two years.

"While the customer response to our pressurized lost foam casting has been very positive, we continue to be part of the engine OEM's long new product development cycle that has full-scale production for components one to two years out,' said Dickirson.

A Slight Change in Focus

When Mercury Castings first began quoting non-captive lost foam work, its focus was to target jobs that:

* have complex geometry;

* have part volumes from 25,000500,000/year;

* are used in the non-automotive, small-engine manufacturing industries;

* have sales volumes of at least $500,000/year per part number. For the most part, this focus hasn't changed except: "We are now working with automotive on complex medium volume and service components," said Dickirson.

According to Dickirson, Mercury Castings recently secured a commercial job from a major U.S. automobile manufacturer for the production of lost foam cast cylinder heads. This job is expected to ramp up next year.

Mercury Marine projects that it will grow its commercial casting work from its current 200/a of production to 50% by 2006. This growth will be with lost foam and diecasting. Based on this projected growth, Mercury is preparing itself for the installation of a second lost foam line in its new facility. By utilizing sold capacity tracking software, the firm will determine the need for the second line by the end of this year. Installation and ramp-up of a new line will take eight months.

Lessons Learned

The two biggest lessons that Mercury Castings has learned over the last 15 months are related to gating and qualification.

In terms of gating, the pressure lost foam process has forced Mercury to revisit how to feed metal to thin sections. For some castings, the thin sections would freeze off before the pressure could impact the rest of the casting. Without any predecessors from which to learn the rules of pressurized foam gating, Mercury had to work through the development issues itself.

In terms of component qualification, the firm didn't properly estimate the extent to which it would have to requalify existing lost foam components for the new pressurized lost foam line or the lengths it would have to go to qualify new production parts for the process. According to Dickirson, "With a new process, customers always are cautious. We just underestimated the time it would require to run these components through design reviews, FMEAs, prototype runs, etc."

Despite these obstacles, Mercury Castings believes it is on schedule with its five-year strategic plan to turn up the pressure on the lost foam market.

"We know we made the right decision with the new lost foam casting facility," said Dickirson. "We have no regrets."

Mercury Marine-Mercury Castings Div.

Fond du Lac, Wisconsin

Year Founded:          1969.

Metals Cast:           356, Xk360 (se]f-developed), 364, A380, A383,
                       390, 391 self-developed Mercosil) and 515
                       aluminum alloys.

Casting Capabilities:  Lost foam, diecasting and low-pressure permanent
                       mold.

Melt Capabilities:     On-site smelting operation to produce all
                       low-copper, marine specialty aluminum alloys;
                       and conventional reverberatory melt and hold
                       furnaces.

Size:                  More than 200,000 sq ft.

Key Markets:           Captive--inboard and outboard marine engine
                       components; non-captive--engine components.

2001 Production:       40 million lb (85% diecasting; 15% lost foam).

Employees:             More than 400.

Corporate Officials:   Fred Brightbill, president-Mercury Marine; David
                       Michaelson vice president of
                       manufacturing-Mercury Marine; Vic Schutte vice
                       president of strategy-Mercury Marine; Dave
                       Dickirson, director of Mercury Castings; Dave
                       Grebe, plant manager; John Bebrendt, lost foam
                       area manager; and Tim Newman, sales manager.