Amir K. Shadab envisions controlled expansion at his foam products company. Literally.
Sebastian, Fla.-based MDI Products LLC has adapted Italian equipment and a process long used to make shoe soles to injection mold an array of soft, colorful foam products from cross-linked polyethylene pellets with precisely calculated expansion and density factors.
The process - developed during the past few years with the help of retired consultant Don Nelson, a former partner in Adrian, Mich., rotomolder Rotoplastics Corp. - eliminates the costly, time-consuming middle step of making such products from bun stock. Traditionally, a foam slab had to be die cut to an approximate thickness and shape, then compression molded or vacuum formed into the desired end product.
The name of the 3-year-old MDI stands for Macho Direct Inject, which reflects the company's ties with affiliate company Macho Products Inc., a Sebastian-based vinyl nitrile dip molder that Shadab also controls. The 200-employee, 22-year-old Macho Products also holds a minority stake in MDI, which has four employees. Macho makes proprietary trauma-protection foam products used by law enforcement officials and martial arts practitioners.
Shadab grew up and was educated in England, came to the United States in 1970 and earned a master's degree in business administration from Harvard University. He is chief executive officer of both companies. He joined the Macho Products board five years ago, a couple years before buying a majority stake in the firm.
MDI makes one proprietary product - the Softwear line of vinyl dipped and injection molded foam knee pads sold at do-it-yourself retail outlets. But MDI sees its future in leveraging the detailed materials, tooling and processing expertise it has gained in injection molding cross-linked PE into a booming custom-molding business.
Nancy Grossbart, MDI's vice president of business development, stresses the significant challenges involved just in getting to that point, including customizing a molding machine that precisely heats the resin to chemically cross-link it once it is injected into a specially designed mold.
``The learning curve is extemely steep,'' Grossbart said in a recent interview at a Columbus, Ohio, district conference of the Industrial Designers Society of America, where MDI had a tabletop exhibit aimed at educating de- signers about the process.
One molding machine and ancillary equipment alone costs about $500,000, and then precise fine-tuning is required of both the compound and tool to obtain the desired result. But, she added, ``We make it very easy for customers to get into the business.''
The mold maker and compounder on any given project also must collaborate closely. Grossbart said MDI ensures the customer talks directly with its mold maker, Creative Mold Co. in Auburn, Maine. MDI now works with two unidentified compounders - one in the United States and one abroad - to tailor the flow properties, tensile strength, densities, etc., of materials for specific end products. Some of the resulting compounds are proprietary to MDI.
She claims the process is very cost-competitive with processes such as self-skinning polyurethane foam or stapling PVC skin to injection molded urethane foam. And, she added, being a closed-cell foam also makes the cross-linked PE products chemical- and water-resistant, in addition to being soft and durable. MDI can make products in varying densities, including as soft as Shore 00 65.
MDI owns one small prototyping machine and two large processing machines, each equipped with six-cavity aluminum molds - a size Shadab calls ``optimum for us.''
Process takes shape
In a recent telephone interview, Shadab explained how the process works: The injector unit moves on a rail, which can be mounted in a linear or circular fashion, and employs hydraulic pressure to inject resin sequentially into each mold. Each mold cavity is smaller than the finished part's desired size, to allow for expansion.
``There is a relatively long cooking cycle - from six to 10 minutes, depending on the thickness of the part,'' Shadab said. ``When the last mold is filled, the first mold is opening.''
``Draft is extremely important,'' he said. Parts must have an unimpeded path out of the mold, as the chemically expanded foam immediately ``pops into shape.''
Mold design is based on the inverse-ratio principle. For example, ``if there is a 1.8 expansion factor, everything in the mold is 55 percent of the finished part size,'' Grossbart said. A bolt also can be inserted into the mold to create an undercut that increases in size as the part ejects.
The highly engineered end product conforms to an exactly predetermined size and density, and can feature bright PMS-matched colors, textures, undercuts, even living hinges, and such molded-in detail that one can read the text of a tiny trademark.
``It's a beautiful process,'' said Shadab, but there are many interrelated factors to master - the compound, the mold and the way it is processed, including such matters as barrel temperature, mold temperature and back pressure.
Shadab said MDI is collaborating closely with the Italian machinery makers, who have been using such equipment for more than 30 years to make shoe components from PVC, ethyl vinyl acetate, thermoplastic olefins and urethanes.
``We feel that the potential market is enormous'' for cross-linked PE foam products, said Shadab. He said that MDI, which expects sales of about $2 million this year, is well-capitalized, but did not elaborate. This month, Shadab is heading off to Italy again, to negotiate the purchase of a third large processing machine. A machine can work eight-hour shifts, nonstop, with two operators.
``You can amortize costs very quickly,'' he noted. ``The mold cost is the biggest cost for the customer.''
Meantime, MDI is busy targeting the industrial design community.
In April it participated in IDSA district conferences in Columbus, Philadelphia and Minneapolis, and may exhibit at the Dulles, Va.-based association's national convention in Monterey, Calif., in late July.
``This year, we're attacking the design market,'' Grossbart said. ``If you go to purchasing people, they just say, `How much?' '' She claims the response from designers has been positive, once they grasp the concept and its possibilities.
``Part of the design process is to design thickness out of the part,'' Shadab said. ``We can remove most of the polyurethane's thickness, and still achieve its performance properties.''
MDI is targeting the automotive market for such applications as console covers, where PE foam can be attached to an ABS structural core, which he said offers weight savings over currently used materials. Shadab also sees uses in the marine and consumer-product markets, where the foam's resistance to water and chemicals provides an advantage.
But how will tiny MDI keep pace if business takes off like a rocket?
Shadab says a joint venture or licensing venture is possible if, for example, an automaker wants to produce cross-linked PE products on a huge scale.
``We are in it for the long haul,'' he maintains. ``We want to be a leader in this technology.''