Metalcaster of the Year: GM's SMCO: General Motors' Saginaw Metal Casting Operations recently developed and installed a unique version of precision sand technology, earning it the title of Modern Casting Metalcaster of the Year.

Saginaw Metal Casting Operations Saginaw, Michigan 

Year Founded: 1919.

Facility Size: 1,854,000 sq. ft.

Metals Cast: 319 and 356 Aluminum.

Casting Process: Precision sand, green sand, lost foam, semi-permanent mold.

Casting Size: 28 to 115 lbs.

Monthly Production: 7,258 tons.

Employees: 1,000.

Several of the men on a tour of General Motors (GM) Saginaw Metal Casting Operations' (SMCO) new precision sand line in May already were well acquainted with the process. And they should have been. They were direct competitors of the new engine cylinder block producer, and their companies use their own versions of the precision sand casting method.

In promotional pieces leading up to the scheduled tour, GM explicitly told prospective attendees that all were welcome, even competitors. The company didn't want anyone to miss out on the opportunity to see this unique version of a process that is quickly coming to dominate the automotive castings landscape.

So, why is this highly lucrative, elite process so openly shared among competitors?

"When we show the folks what we're doing with precision sand, other suppliers have used that process," said Arvin Jones, manufacturing manager for GM casting and components. "There's a lot of technology sharing."

But that technology sharing only occurs among an elite group of manufacturers who have the capability to undertake such a process. If any old competitor were to come along and try to replicate the ins and outs of Saginaw's specific version of the technology, it would take considerable time, capital and a very good relationship with the existing precision sand supplier base. When SMCO began installing the process in 1999 with benchmarking and development, it already had strong ties to the other groups who were in the know. Four years later, it purchased production equipment, and in 2004, the melting and holding furnaces, core lines and finishing equipment finally were installed. The company began ramping up production in 2005, reached higher volumes in 2006 and is now hitting full production in 2007.

It's taken eight years and approximately $92 million to add precision sand to the facility's existing green sand and lost foam operations (it has more recently begun installing semi-permanent mold lines), and today, SMCO's investment has changed the company from a traditional iron block giant to a cutting-edge aluminum block producer. And it earned it the title of MODERN CASTING Metalcaster of the Year.

Shifting Gears

SMCO produced close to 4.3 million iron cylinder blocks in 2004. In 2007, it won't produce a single one. The changeover to precision sand meant a complete revamping of the product mix, not a gradual shift.

When GM eliminated production of its Generation III engine cylinder block, SMCO stood to lose its lifeblood, not to mention a significant portion of its workforce. For future engines, the parent company was going to strictly produce the Generation IV block, which had been fully outsourced in the past. The move followed a company-wide shift from iron to aluminum blocks. For SMCO to take part in making the new engine components, it had to be able to produce a product with material properties and dimensional tolerances as great as the competition. It had to go to precision sand.

The contract for the increase in Gen IV production wasn't handed to SMCO, though; the facility had to compete for it just like any competitor would. In the end, GM found it more financially sound to perform the expansion than to outsource more blocks.

"We feel like we're part of GM, but we have to compete," said Kenneth Stahl, senior manufacturing engineer. "So for us to be an asset to GM, we have to provide a superior product, and it has to be cost competitive."

The majority of the floor space in the old Saginaw plant was devoted to green sand lines and pumping out iron blocks. Most of that space has been cleared out for the precision sand line, but the new line is not currently running at capacity. While SMCO initially envisioned a one-to-one tradeoff from Gen III iron to Gen IV aluminum, it is now producing fewer of the new blocks than the old. The facility would have to tap into its residual furnace space to rev up to full capacity.

"We'd like to be fully utilized," Stahl said. "We like to be ready so if we are challenged, we can meet the demands."

What's in the Name?

So what exactly is precision sand? Precision? Understood. Sand? Seen it before. Both words are self-explanatory, but they come together to offer more than just a nifty title. The goal of the precision sand process is to produce high core-print quality with low dimensional variation (precision) in a bonded molding media (sand). Using numerous cores held together in a flaskless package, the internal passages and external geometry of castings are produced without the use of a traditional mold or pattern plate. All cast features produced through precision sand processes achieve about +/- 0.04-in. (+/- 1-mm) tolerances.

But that's about where the similarities among the world's precision sand outfits end. Variations are possible on myriad steps along the way toward achieving that kind of accuracy. SMCO's new line operates what has been dubbed the Saginaw Precision Sand Process, "a cross between the Cosworth process and low pressure precision sand," according to Stahl.

SMCO first moves away from the pack with its pre-treatment of the iron cylinder liners that are placed in the core packages that mold the shape of the cast engine blocks. Many precision sand operators preheat their liners in order to fire off solvents; others blast them with a particulate. SMCO originally found that preheating cost it considerable time and energy, and the hot iron in the packages degraded the microstructure of the final castings. So, it worked initially on the assumption that it would not preheat the liners. However, when that failed, the metalcaster shifted gears and determined a window of temperature that would remove the liner's coating but wouldn't affect solidification times and cause the liner to react with the bonding agent in the molding sand. To that end, they have developed a process in which a pre-heating furnace takes the liners to an undisclosed temperature for a designated amount of time before a cooling unit brings them quickly back down. The lowered temperature helps to achieve the desired material properties.

According to Jones, the most critical difference between the Saginaw process and other versions of precision sand comes from another step taken to achieve superior material properties--the use of chills in its core packages. SMCO chills the bearing area of the bulkhead in its engine cylinder blocks--nothing new there--but it also chills the side walls of the inner bore, giving the blocks industry leading material properties: 105 MPa fatigue, 350 MPa ultimate tensile strength, 270 MPa yield strength and 3.5% elongation.

Once the core package has been assembled and the liners put in place, the unit is inverted and bottom-filled with an electromagnetic pump, meaning the blocks are actually filled from top to bottom. The packages are then roiled so that they cool in the upright position. This eliminates the need for extraneous risers, because the core package's runners and gating system feed the casting and reduce the possibility of shrink.

This direction of filling and orientation during cooling is another of the significant differences between the Saginaw Precision Sand Process and other precision sand casting facilities around the globe, and it helps SMCO achieve yields of almost 72%, which represents a nearly 50% improvement over its largest competitor. But while the inverted-fill-and-flip progression helps give Saginaw's process its character, it also lends itself to new challenges.

"The problem we've seen is a lot of the changes in [other systems] don't work," said Paul Greskowiak, senior quality analyst. "Changes on one end of the mold affect the other end. We have to treat the whole gating system as one, and we're still having difficulty reducing shrink."

The company's external scrap rate currently is 0.6%, but it expects to achieve lower than 0.3% in the near future. If it can fix some of the existing problems and reach that goal, it would be an industry leader in that area as well as material properties. Internal scrap rates are at 8%, below the company's requirements.

GM also has gone to greater lengths to automate the process of precision sand casting than other facilities. While the actual casting processes--coremaking, core package assembly and pouring--generally are automated no matter where in the world the production is being done, GM has included automated shuttling among the processes, for the first time bringing automatic forklifts to a metalcasting floor.

"We saw those [automatic forklifts] in a manufacturing plant," Stahl said. "They said they wouldn't work in a metalcasting facility. We said why not? We've done a lot of things that have never been done in a metalcasting facility."

Gaining Leverage

Prior to the precision sand expansion at the Saginaw plant, GM sourced thousands of blocks through its main competitor, Nemak, Monterrey, Mexico. And to this day, the company still sources thousands of engine cylinder blocks through Nemak. Nevertheless, the company found it necessary to bring the capabilities in house.

"There are benefits to the balance of having components produced both inside and out[side the company]," Jones said.

In theory, GM could produce all of its precision sand blocks in-house, or it could outsource them all, but either situation would have its downsides. If the company were to rely solely on externally produced goods, it would have no leverage on the market, and competitors could charge exorbitant prices. As a producer and consumer, GM can have a direct effect on the economics at work in the marketplace. If the company were to produce everything in-house, it would risk becoming technologically isolated. It would no longer have competitors roaming its facility aisles, and it wouldn't be invited to do the same.

"You want to maintain good healthy supplier relationships for technological capability," Jones said. "But there are some things that we like to keep close to the vest because of the [proprietary nature]."

Automation Station

Competitors on a tour of SMCO certainly wouldn't be familiar with everything going on at the facility. In addition to the automatic forklifts, SMCO holds 14 patents on various pieces of equipment and processes. In all, 80 robots play various roles throughout the plant.

"There's a lot less of the human element," said Jay Roszatycki, general supervisor.

This automation may represent some loss of floor workers--at SMCO, the man-hour per unit target is 0.6. But according to United Autoworkers union co-chair of manufacturing Jim Clevinger, the working class is beginning to accept the fact that there will never be as many manual jobs in manufacturing as there once were.

"The automation was tough at first," Clevinger said. "But I think [the floor workers] eventually saw it was ergonomic."

For one thing, Clevinger notes that the plant has become a far safer place to work. The facility hasn't suffered a lost time injury since January. For another, there are now more opportunities to learn new trades and advance in the company in different ways.

"If you wanted to be a stale person, you'd prefer the old way," Clevinger said. "But now, you can go out and find a new challenge everyday. I got in from the ground floor and did things I never thought were possible for me. I'd prefer to work in precision sand."

Plant manager Rex Blackwell said that the ease of the personnel change has been critical to the success of the facility's expansion.

"The technology for this process is out there," he said. "The difference here is our joint relationship with our union partners and the willingness of this workforce to embrace change."

A Changed Plant, Company

Two photos stand out in and around Stahl's desk within the Saginaw administrative offices. But they're not of his daughter in an "I Love My Dad" frame and a shot of his son in an existential pose on his new album cover. Rather, the most striking images are two photos of the SMCO plant itself.

In one photo, the facility in 1956 is scarcely visible, surrounded by black smog. But in the second photo, the sun is shining, and a bright orange-yellow facade is visible. It's a metalcasting facility after all, not a cloud factory.

And the metalcaster hasn't simply cleaned up its act in the normal course of adding emissions-control equipment. The entire process of precision sand leads to a cleaner running and burning facility, bringing about a new culture of manufacturing surrounding its facilities in Saginaw. And the bottom line has reflected it.

SMCO can't measure its success in the same way that most metalcasters can. As a captive facility, it does not produce sales dollars per se. But the metalcasting facility showed a 15% cost reduction from 2005 to 2006, which led the accounting department to believe that a 21% reduction would be possible this year. Currently, it is seeing 23.7% lower costs. The metalcaster also judges its success by looking at what it can do for the company to which it owes its existence--GM.

"[Looking] at dollars and quality metrics, in the last four to five years, we've made huge gains in both cost and quality," said Kai Spande, engineering manager. "And from [GM's] customers' perception, we have been able to reduce costs on engine warranties."

SMCO isn't the only place that GM has invested significant amounts of money into casting processes. Since the beginning of this year, the company has brought more than $160 million to the table to improve metalcasting operations. In addition to the precision sand operation at Saginaw, that includes another $63 million to install semi-permanent mold lines at SMCO, a $61 million investment in its Defiance facility, and a $44 million upgrade at its Bedford plant.

At a time when other major car companies, particularly Ford, are hemorrhaging casting operations, those investments represent a significant leap of faith in in-house metalcasting. "We view castings as a strategic part of GM," Jones said. "We think it's strategic for us to take advantage of that globally. We feel very strongly about maintaining the casting business in GM Powertrain."

Saginaw Metal Casting Named Metalcaster of Year

MODERN CASTING selects its Metalcaster of the Year based on the recipient of the annual American Foundry Society Plant Engineering Committee's Plant Engineering Award. The award is presented annually to a North American metalcaster that has demonstrated engineering expertise to advance the capabilities of the industry. General Motors' Saginaw Metal Casting Operations, Saginaw, Mich., was chosen for the installation of a unique version of precision sand casting, making it one of only several facilities in the world using the technology.

Past winners include Dotson Iron Castings, Mankato, Minn.; Hayes Lemmerz Montague, Montague, Mich.; John Deere Foundry, Waterloo, Iowa; International Truck and Engine Corp.'s Waukesha Manufacturing Facility, Waukesha, Wis.; Neenah Foundry Co., Neenah, Wis.; Mercury Marine-Mercury Castings Div., Fond du Lac, Wis.; and American Cast Iron Pipe Co., Birmingham, Ala.

Small Lessons From a Big Company

For most metalcasters in the U.S., the technology at play in large-market facilities like Saginaw Metal Casting Operations (SMCO) is out of reach. The investments necessary just aren't possible. But according to executives at General Motors (GM), every metalcaster can learn a few things from the company's experiences.

1. Ensure capital and knowledge--Whether you're GM or a small shop, before any expansion, a company must honestly appraise whether they are capable of bringing adequate capital and know-how to the table. "Are you capable from a cost and quality perspective?" asked Arvin Jones, manufacturing manager for GM casting and components.

2. Work with the government--Depending on where you will be setting up shop, local and state incentives and tax breaks could make an otherwise cost prohibitive project a reality. Work with as many government organizations as you can to determine what public funds are out there and whether you can acquire them.

3. Duplicate production exactly when using test runs--Working out the kinks of full production in a prototyping phase can benefit any facility looking to expand and add a molding line, but it is important to match the intended process exactly.

4. Ensure that all equipment is compatible--SMCO worked with several suppliers to bring together all of the equipment it needed for the considerable expansion. But in at least one case, they overlooked a piece of software that was needed to make two pieces of equipment compatible, causing a temporary setback.

Shea Gibbs, Associate Editor

Saginaw Metal Casting Operations Products for 2007 Model Year

    Part Name         Customer     Engine Application

  4.2 L 16 Block     Flint South     Vortec 4200 16

  4.2 L 16 Head      Flint South     Vortec 4200 16

    4.8 L Head         Romulus      Vortec 4800 V-8

    5.3 L Head         Romulus      Vortec 5300 V-8

   5.3 L High-         Romulus      Vortec 5300 V-8
 performance Head

5.3 L Gen IV Block     Romulus      Vortec 5300 V-8

    6.0 L Head         Romulus      Vortec 6000 V-8

6.0 L Gen IV Block     Romulus      Vortec 6000 V-8

6.2 L Gen IV Head      Romulus      Vortec 6200 V-8

    Part Name              Vehicle Application          SMCO Process

  4.2 L 16 Block        Buick Rainier; Chevrolet         Lost Foam
                        TrailBlazer, TrailBlazer
  4.2 L 16 Head         EXT; GMC Envoy, Envoy XL;
                                Saab 9-7X

    4.8 L Head        GMC 1500/2500 Sierra, Yukon,       Green Sand
                       Savana 2500/3500; Chevrolet
                       1500/2500 Silverado, Tahoe,
                           Express (2500/3500)

    5.3 L Head        GMC and Chevrolet 1500 Sierra      Green Sand
                      and Silverado; GMC Yukon; GMC
                         Yukon XL and Chevrolet
                        Suburban; GMC Savana and
                      Chevrolet Express; Chevrolet
                                Avalanche

   5.3 L High-       GMC and Chevrolet Extended Cab      Green Sand
 performance Head         Sierra and Silverado

5.3 L Gen IV Block    GMC and Chevrolet 1500 Sierra    Precision Sand
                        and Silverado; GMC Yukon;
                       GMC Yukon XL and Chevrolet
                        Suburban; GMC Savana and
                      Chevrolet Express; Chevrolet
                                Avalanche

    6.0 L Head           Yukon Denali/Yukon XL;          Green Sand
                           Chevrolet Suburban;
6.0 L Gen IV Block    3500 GMC Sierra (2500/3500);     Precision Sand
                     Chevrolet Silverado (2500/3500)

6.2 L Gen IV Head      Cadillac Escalade, Escalade       Green Sand
                         ESV & Escalade EST; GMC
                     Yukon Denali & Yukon XL Denali