Engineering Barbie

DN Staff

December 18, 2000

8 Min Read
Engineering Barbie

El Segundo, CA -Mattel Corp.'s engineers have a strange way of playing with Barbie. They're far more likely to tear her limb from limb than to invite Ken over for a tea party. Sorry Ken, but sometimes you have to break a few dolls to build a better Barbie.

Though already a hugely popular icon, as evidenced by last year's sales of $1.5 billion, Barbie continues to evolve in ways that go beyond a new outfit or accessory. And Mattel's engineering staff continually looks for ways to incorporate all the new features that make her more fun to play with, less expensive to make, or both. "It's not always fun and games around here," says Isaak Volynsky, Mattel's corporate director of new technology.

Get under Barbie's skin as Volynsky has, and you'll notice that Barbie's most recent enhancements have relied on materials innovations. This year alone, three such advances have made Barbie more attractive than ever: New elastomers have given her a more lifelike body. Engineering thermoplastics have improved her complexion. And developmental water-based paints could soon result in a face that goes easier on the environment. You may not care much about Barbie-though it's really okay if you do-but each of these materials taps into something bigger than a doll. "All three have broader applications than toys," Volynsky notes.

Do the twist. Barbie might have seemed a bit stiff in the past, but a newly developed articulated waist-or "twisty tummy" as the 10-and-under set call it-now lets her bend in ways she's never bent before. Volynsky says the flexible waist grew out of a continuing effort to make Barbie's movements more lifelike. "You can't expect a handful of plastics to behave like a complex human system," Volynsky admits. "But we can try to mimic it."

Mimicking the physical movement of a waist turned out to be the easy part. A fairly straightforward acetal ball-and-socket joint forms the flex waist's skeleton. Finding the right elastomer to cover the joint proved more difficult. "Most importantly, the elastomer had to be flesh-like," Volynsky says. This fleshy quality calls for a material that combines softness without stickiness-a problem for many soft elastomers. "Low durometer materials tend to be tacky," Volynsky says, noting that some candidates even leached oil onto their surfaces.

The elastomer also had to balance the fleshy feel against a sometimes-contradictory list of physical and mechanical properties:

Flexible enough for Barbie to "stay" in place when posed

Tensile strength to survive bite and tear tests

A low compression set to keep creases at bay if Barbie stayed in one position for too long

Environmental resistance to UV, heat, saliva and perspiration

Mattel engineers scoured supplier literature for more than a year, finding nothing that would meet all the requirements. "We tested all available soft elastomers-even the ones we thought wouldn't work," Volynsky recalls. "After an exhaustive search, we concluded that the material did not exist," agrees Joe Cristina, Mattel's vice president of inventor relations.

Mattel finally got a break during one of symposiums it holds annually to evaluate new technologies. Here, engineers ran across an alloy of styrenic block copolymers that looked like it would fit the bill. From that point forward, it still took two more years of development work with the elastomer supplier, GLS Corp. (McHenry, IL), to fine-tune the material and molding process.

At the beginning, the development work involved translating the subjective notions of "fleshlike" into specifications to give to GLS to send to its compounding lines. Rather than starting with firm engineering specifications, Mattel de- signers conducted touch tests to determine which GLS "Ultrasoft" grade felt the most like skin. "We started with a 40 Shore A grade," says staff engineer Henry Reyes. "That was GLS' standard soft material at the time." As the designers laid their hands on more and more elastomer grades, a consensus emerged for a far softer material. Mattel ended up specifying an elastomer with 10 Shore A durometer. "It almost has the softness of foam," Reyes says.

From bathware to Barbie. Barbies that wind up in the display cabinet rather than the toy chest also challenge the toy maker's ability to find the right materials. Volynsky points out that that collectible dolls have to be just about perfect-with defect-free surfaces, finely detailed features, and the solid feel of a small statue. "For collectors, each and every detail is important," he says. In the past, dolls in this category sported porcelain bodies-and price tags that start at $200. For its latest line of collectible Barbies, however, Mattel created a thermoplastic doll that passes muster with collectors but costs only $60.

These "Fashion Model Barbies" feature solid bodies injection molded from PBT, an engineering thermoplastic best known for bathware, countertop, and other durable applications. "This is heavy-duty stuff, not something usually used for small, detailed parts," Volynsky notes. To meet its engineering and aesthetic requirements, Mattel and BASF Corp. (Mt. Olive, NJ) had to develop a custom PBT formulation. Called "Silkstone" it contains proprietary impact modifiers and a 30% mineral filling.

"Impact modification was the most important thing," Volynsky says, explaining that the Fashion Model dolls endure a series of drop tests that would shatter porcelain. The tests disallow any ductile or brittle failures. In the toughest test, the half-pound Barbie falls 36 inches onto an outstretched arm so that her tiny thumb bears the full force of the drop. So brutal is this fall that the impact-modified doll also needed a helping hand from a design change. "We ended up angling the thumb in closer to the hand," reports Reyes.

Silkstone's durability also enabled Mattel to develop a simple cardboard box that doubles as a display. Porcelain dolls, by contrast, require far more protection, so they typically come in a more elaborate box and custom foam wraps-a packaging approach that Volynsky describes as "humongous and expensive."

Silkstone also imparts just the right look and feel to the Fashion Model Barbies. According to Volynsky, the inherent heaviness of the filled PBT approximates the weight of porcelain, imparting the heft that collectors associate with quality. And the material also has the defect-free, non-glossy surface that collectors want. "The aesthetics are superior to porcelain," Volynsky insists. The surface appearance has been so good, in fact, that Mattel uses the PBT parts straight off the molding machine. "We had our doubts at first because solid, filled parts are so susceptible to surface defects," he says. But Mattel's molding know-how and a yearlong process development effort prevailed, eliminating the sinks and swirls that would have otherwise plagued the part.

Despite Silkstone's advantages as a body material, a hairy problem did prevent its use on the doll's head. PBT couldn't accommodate the tiny holes that secure Barbie's hair, so a hard vinyl compound forms the head, and Mattel color matches it to the Silkstone.

Volynsky's team briefly considered hard vinyl for the body parts. But the vinyl parts, which would have been hollow, couldn't provide the heft of solid PBT, and they exhibited a chintzier tactile quality. "Vinyl just didn't have the qualities we needed for this market," Volynsky says.

The eyes don't have it. Barbie may not be crying over the solvent in her eyes for long, thanks to a developmental water-based paint system from a confidential supplier. According to Volynsky, this environmentally friendly system has a low enough solvent content to win an exemption from federal VOC regulations, and it may soon replace the solvent-based paint now used to put on Barbie's face. In August, as part of an effort to cut solvent use, Mattel tried the system-which consists of the paint, a spray gun, and an environmentally friendly cleaner-on selected manufacturing lines in Indonesia. "The results look very promising," Volynsky says.

The paint is remarkable on several scores. For one, it dries in a "few seconds," Volynsky reports. And drying speed matters, given that Barbie's eye and face details require roughly 20 consecutive spray-paint operations. What's more, Volynsky says the new paint adheres to just about any plastic, including troublemakers such as polypropylene and other olefins. Finally, the water-based paint offers the same color fastness and gloss levels as its solvent-based predecessors. "You would need a microscope to tell the difference, and even then I'm not so sure you could tell," Volynsky says.

For more information

Go to www.designnews.com/info or enter the number on the Reader Service Card:

Elastomers from GLS Corp.: Enter 545PBT from BASF: Enter 546Water-based paints from Mattel: Enter 547

Attractive but complex

Look inside Barbie to see just how complicated she really is.

Don't believe the rumors. Barbie is not easy. "She's very complex," says Volynsky. The flexible-waist Barbie consists of more than 20 parts.

The torso has four pieces-two upper and two lower. Two arms with insert-molded sockets engage arm holders in the torso, for four more pieces. Each leg has a two-piece armature plus an attachment pin and overmolded elastomer for eight more parts. The flexible waist itself consists of a two piece ball-and-socket joint covered by an elastomer skin.

Mattel puts elastomer skins over the legs and waist armatures in a overmolding process that saves assembly steps. The flexible waist, for example, has no glue to attach the elastomer to the adjoining torso pieces. Instead, a molded-in lip in the torso entraps the edges of the elastomer, forming a nearly seamless joint.

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