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March 4, 2003

12 Min Read
A multimolding mall-crawl


Netstal displays an array of multicomponent parts molded on its SynErgy 2C Series machines in its shop window here in the Multimolding Mall. SynErgy 2C multishot presses are available up to 660 tons. Newer technology has been developed for molding clear jewel box tops and colored bottoms on the same press in a stack mold. The parts are automatically removed and assembled. This offers more output at lower cost.

Krauss-Maffei has been building multimolding presses since the early 1980s, and builds them today, up to 6000 tons. K-M?s latest, in which the second shooter comes into a turntable platen from the moving-platen side of the press where the ejector usually sits, will be on display at NPE 2003.

With conventional injection molding jobs migrating East, many in the West see the value-adding processing specialty of multiple-material/multiple-color molding as a competitive advantage.

Multimolding? What?s that, you ask? It?s shorthand for injection molding parts with more than one material or color. In these hyper-competitive times, many in the industry believe multimolding is an extremely important niche specialty that should be in any North American Free Trade Agreement (NAFTA) molder?s survival kit to help them improve their customer?s productivity.

We?re going to take a look at what?s available from the suppliers?window shopping, if you will. But, while strolling through the aisles we?ll also bump into others who have their own opinions about the state-of-the-art, global market conditions, opportunities for growth, and, regrettably, multimolding problems.

Ready? Let?s crawl.


Husky says most multimolding presses are less than 200 tons, and most multimolding activity presently is in Europe. But it adds that activity in North America and Asia is on the rise.

The Directory
Welcome to the Multimolding Mall. Our first stop is the Mall Directory. As we can see, multimolding has evolved into a bewildering array of different forms since the technology really started to take hold in the early 1980s. Generally, they fall into two basic categories: multishot and multilayer molding.

Multilayer (also known as coinjection or sandwich molding) feeds two materials into a mold cavity in such a way that one material forms the core of the finished part and the other material forms its skin. Multishot molding?the main reason for this mall-crawl?is the sequential addition of different components, or the overmolding of one material or more over another.

Multiple injection units for delivering the different components can be configured in every way imaginable?horizontally, vertically, piggyback, in parallel?and in combinations of the same. Some multishot machinery suppliers have specs for systems with up to seven different shooters. One multilayer molding method can deliver two different materials using only one injection unit?another does it all inside the mold.

Leaving the Directory, we begin to hear some troubling whispers about multishot molding as we start our window shopping. ?Psst,? we hear. ?The machinery isn?t the problem. It?s the molds.?


Not every Mall-crawler feels we suffer a multimoldmaker shortage in the U.S. ?I believe that the supply of multishot moldmakers is growing sufficiently to meet demand,? says John Onzik, president of custom molder Dickten & Masch Inc. (Nashotah, WI), who multimolded this power tool part.

Heart of the Problem
Molders in the NAFTA region have difficulty finding moldmakers here capable of building reliable multishot molds. As a result, they frequently ask their machinery suppliers to provide turnkey systems?systems with tooling included. We bump into Jack Avery, manager of operational assets for GE Plastics (Pittsfield, MA), and ask his opinion.

?Tooling is difficult, as few toolmakers are familiar with the requirements of the multishot molding,? Avery says. ?The simplest kinds are those for components that are actually inserted into a second mold prior to the second shot. More difficult are the molds incorporating rotating cores or cavities. This is complex tooling with very few sources. If the mold is not done correctly the first time, it may be very expensive to correct.?

Outside the Krauss-Maffei (Florence, KY) store, a company source has a word or two about multimold costs: ?The problem can be that the tools are more expensive than single-shot molds?for sure. But you don?t need the fixing costs and handling costs to assemble, for example, two plastic parts into one. The real task is to find specialized moldmakers.?

Many of the machine suppliers say they have three options: a cadre of experienced moldmakers they can draw on to help them deliver turnkey systems; build the molds themselves; or act as project managers, steering their customers to specialists. However, suppliers often are reluctant to spread the word about their favorite multimoldmakers for competitive reasons.

?We do offer ?turnkey,? what we refer to as sub-systems consisting of the machine, mold, and takeout device,? says a source at Netstal?s shop. ?We do have some very good technology partners for molds, but I agree, they are not easy to find, particularly for the higher cavitations. I can give you some good names, but I hate to make it too easy for the others.?

Internalize Expertise
Out in the hall we?re stopped by a molder, Rick Spindler, manager of new product development at Kaysun Corp. (Manitowoc, WI). He tells us that he had 15 years of engineering and sales experience with a dedicated multimolder before joining Kaysun. He questions the effectiveness of molders looking to machinery suppliers to solve their multimolding problems.


All-electric multimolding? Why not? Toshiba asks. Everyone knows that injection units consume the most energy on any molding machine. So, if you?re using two or more, why add to your costs? Toshibas feature full energy-saving a-c servocontrol and both shooters can operate independently for faster cycles, reportedly slashing operating costs by 80 percent. Even a servodriven rotary platen is available as an option.

?If I had to pick one factor that is most critical in multishot molding, I would have to lean towards the tooling technology,? says Spindler. ?There are some good custom multishot molders in our part of the country. The one thing they all have in common is in-house tooling expertise.?

Spindler continues, ?Indexing clamp plates and spinning center platens can be injection machine driven, but tooling precision and know-how are what make these companies successful. I?ve always felt that if you can build multishot tools, you can build anything. The level of precision in many of these molds can rival that of fineblanking dies.?

He says he believes molding machine salespeople must struggle with these issues because most don?t understand enough about the technology to talk knowledgeably about it, much less help a molder choose the correct machine design for a particular application.

?With the numerous multishot molding technologies, both creativity and versatility are critical,? he says. ?The machine that you bought last week to mold a pushbutton doesn?t work for the cover/gasket job you received this week, or the toothbrush you will quote next week.?

To make matters worse, Spindler says the offerings from injection molding machine manufacturers vary considerably, so ?as a custom molder, bringing machine suppliers, toolmakers, and material people together just so you can quote a job usually isn?t practical. You have to develop the expertise internally.?

Luck of the Draw
Even with considerable internal toolbuilding experience, there can be problems. That?s the word from Gunter Weiss, president of custom micromolder/ molder/moldmaker Precimold (Candiac, PQ), who passes us by, shaking his head. He?s running single-shot parts on his new multishot machine.

?I am sad to say that we have a 150-ton Engel that can do multishot molding?two-color molding with or without rotating. It even does coinjection. But we have yet to do any of the above,? says Weiss. ?In more than 18 months we have not yet found a customer interested in this kind of work.?

Another custom molder/micromolder is much more upbeat?Stuart Kaplan, president of Makuta Technics (Columbus, IN). A member of the global Sansyu Group of companies headquarted in Japan, his company has inherited an expertise in both multimoldmaking and machines.

Makuta has always had multimaterial injection molding as part of its business strategy, says Kaplan. ?Makuta and Sansyu have developed unique systems for engineering and producing multimaterial injection molded parts. We have no trouble acquiring multishot molds. Sansyu builds them. In fact, we would not want a machinery supplier to supply molds with machines, as it reduces our flexibility in creating new opportunities for multishot molding for our customers.?

Sumitomo (Norcross, GA) works directly with Sansyu to develop micromolding machines from 15 to 30 tons and has done so for years. As a result, Sansyu is able to simultaneously incorporate improvements in its mold technology with improvements in machine hardware and software.


Like multishot molding, coinjection molding is not standing still. For example, here in this Mall window we see Ferromatik Milacron?s patented coinjection manifold technology. It reportedly brings a new level of versatility to this value-adding process, including, but definitely not limited to, multicavity hot runner coinjection; multigated, hot runner, single-cavity coinjection; or even multicomponent, two-color, coinjection overmolding.

Multishot sourcing can be a problem, but what about multishot technology in general? Our question is answered by a passing NAFTA multimolder, who asks to remain anonymous. Multimolding is the prime breadwinner at his organization?14 of his 18 presses run multishot tools 24/5.

?Rotary platen molding is a very expensive proposal,? our anonymous molder says. ?The disadvantages include the cost of machine and the cost of the mold. Multiple cores lead to more expensive molds?reflex inserts for lenses are very expensive, and three-station molds end up being cost prohibitive.

?I think that people make the technology more difficult than it needs to be,? this molder continues. ?Our organization has several hot-transfer injection molding machines. With some assistance from a subcontractor, we have retrofitted our machines in-house with a second barrel. We use servorobots with fully capable wrist actions to demold parts and then insert these first station parts in the second station. As a result, our tooling is more conventional.?

Europe Leads the World
We hear a recurring refrain in the halls of the Multimolding Mall: Most multimolding work is being done in Europe.

At the Ferromatik Milacron (Batavia, OH) store, a company spokesperson tells us of a market analysis study done late last year. It showed that the European Union (EU) market for multimolding machinery is 10 times bigger than it is in NAFTA. The European molding community, he explains, has had ?a gun at its head,? in terms of global competition, for a much longer period of time. The result is that Europe has had to aggressively pursue such specialties as multimolding to distinguish itself.

?The U.S. does not have the same base, the same critical mass, in terms of know-how, training, and experienced people, as Europe does,? he says. ?I?ve read that the average North American toolmaker is 55 years old. And there?s no real, excellent program here to bring youngsters along. We need a ?center-of-excellence,? or Silicon Valley type of community in this country to train moldmakers, molders, and part designers.?

GE Plastics? Jack Avery generally agrees. ?My experience tells me that the Europeans are much further ahead in this area. Why? My opinion is that they are much more ?technical? in the manufacturing process?they apply much more expertise to the manufacturing process, where we typically have very low levels of experience as machine operators.?

However, all agree with a source from Husky Injection Molding Systems? (Bolton, ON) store, who?s joined us. ?The majority of multimaterials molders are located in Europe, but the North American markets are increasing.? Husky also believes that the clamp tonnage range for multimolding machines also is increasing?one-third of the global market reportedly is now about 200 metric tons, thanks largely to the growing demand for larger parts and increased cavity counts.


GE Plastics? Jack Avery believes multimolding (shown here on a rotomold on a Husky machine) is a good opportunity to for a molding shop to differentiate itself from its competition, improve its productivity, and provide customers with a higher-value product. But, he says, ?This comes at a price?equipment is more expensive, molds are more expensive, and more engineering is required, including early and ongoing involvement in the product design process.?

Opportunity Knocks
While leaving the Multimolding Mall, we?re handed flyers and see advertisements everywhere announcing new developments in NAFTA multimolding. For example, P.C. ?Hoop? Roche from closure molder Erie Plastics Inc. (Corry, PA) stops by to remind us of the three-shot press he?s installed in his company?s Innovation Center to provide customers a total solutions capability. Makuta Technics? Kaplan rushes up to tell us of a breakthrough multimolded sensor technology Sumitomo helped it develop for Texas Instruments (Dallas, TX).

We almost miss a store belonging to Accede Mold & Tool Co. Inc., a U.S. moldmaker based in Rochester, NY, who specializes in building multimolding tools. And machine makers from Asia, Europe, and the U.S. drop hints of some of the newer multimolding systems they?ll show you at NPE 2003 this June in Chicago. There?s evidence everywhere that multimolding is on the rise in North America. But Kaysun?s Spindler stops us at the door with a few words of caution.

Spindler says multimolding, as a whole, is certainly not a ?flash-in-the-pan,? ?gee-whiz? technology. It should be used whenever the product justifies the investment. But he adds that molders need to look beyond one or two possible applications before moving full-speed ahead.

?In that respect multishot molding isn?t much different from any other ?niche? technology associated with injection molding,? he says. ?The costs to operate a multishot plant are higher than conventional injection molding. Tooling and machine maintenance costs increase. Overhead costs increase, too, because twice as many dryers and material handing systems are required. Plus, more technical personnel are needed to support the machines.?

Spindler says it?s not just about machinery, or tooling, or even material selection, for that matter. ?You not only have to bring together expertise in all three to be successful, but in most cases you also need to work closely with the end customer to modify the plastic part to use the chosen tool design and processing method.

?You can?t dabble,? he warns us. ?If you are not willing to invest in a big way in the people, technology, equipment, and tooling know-how that is required to be successful, find another niche.?

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