Injection Molding--The Next 10 Years

As molding evolved over the last decade to include more specialized and sophisticated parts, it also became subject to increasingly stringent manufacturing requirements for cost, quality, productivity, and speed. To cope, some molders embraced new technologies and processes. Gas-assist molding is a prime example. In 1998, it was a rarity; today, it's commonplace. The same goes for multi-material molding, another processing technology that can positively influence costs, quality, and productivity.

Over the next decade, today's manufacturing pressures will only intensify as OEMs demand ever-lower costs, higher quality, and greater productivity. And if these demands don't present enough of a challenge, OEMs will increasingly outsource manufacturing tasks they once handled themselves by requiring molders to take responsibility for product design, development, and assembly. This trend is already well entrenched among Tier 1 automotive suppliers and is now picking up steam in other industries.

With all these changes in the works, custom molders that hope to prosper 10 years from now will need to transform themselves in fundamental ways.

Take more responsibility

This impending transformation is most apparent when it comes to non-molding operations. Today, most custom molders do some assembly, but in 2009 successful processors will do far more. They will be fully integrated into the OEM's product-development cycle and will operate more like a contract manufacturer that has molding as just one of its core competencies. These "product-development companies" will have to select and qualify suppliers, source non-plastics components, manufacture finished assemblies and products, perform quality assurance, and sometimes ship the finished products to the end user.

Increased responsibility doesn't mean the molder of 2009 will need to be expert at, or "own," every aspect of manufacturing the OEM's products. Instead, smart molders will leverage the investments made by other parts of the supply infrastructure--such as machinery or material suppliers--rather than trying to duplicate those efforts. An example of this strategy can already be seen in the design of a thin-wall computer monitor housing made with sequential valve-gating techniques. Here, the molder, toolmaker, hot-manifold supplier, material supplier (GE Plastics), and industrial designers, all worked together throughout the project to avoid wasted cost and time from duplicating each other's technology-development work--in this case, a new manifold for thin-wall applications.

To participate fully in this streamlined product-development cycle, the successful molder of the future will increasingly need to get involved during a product's conception and work in concert with the designer, manufacturing engineer, toolmaker, machine manufacturer, and material supplier. Some of this early involvement goes on today. But given the direction more and more OEMs are taking, molders that can't provide value from the beginning of the development cycle will be seen as marginal suppliers and will be in a precarious position.

Early involvement doesn't come cheaply or without risk. Successful companies will need to invest not just in more complex manufacturing capabilities--such as manufacturing cells or advanced processes--but also in human capital. Industrial designers and engineers skilled in CAD and CAE will take on greater importance within the molding organization.

Look to your cells

Productivity through systems integration within manufacturing cells will be one key to the plastics industry's future growth. The productivity focus in complex, high-volume applications like CDs, DVDs, and so-called "smart cards" has already demonstrated the value of using manufacturing cells. As productivity demands intensify, so too will the use of cells in automotive, medical, personal-care, and electronics markets. Emerging micro-molding applications for parts weighing from less than a gram to 3 g will certainly go into cells as they can't be commercially molded any other way. Despite their high upfront costs and a somewhat risky lack of flexibility, manufacturing cells will likely win over other manufacturing methods because they can integrate many operations, such as insert loading, assembly, decorating, quality testing, and handling for shipping.

One way to combat the high cost and complexity of a typical manufacturing cell will again be a reliance on the supplier infrastructure. Ten years from now, molders will turn more often to the machinery supplier as a system integrator responsible for providing a smoothly operating cell.

In one noticeable shift from the way cells are run today, the manufacturing cells of the next decade will sometimes be set up and run by molders within the OEM's assembly facility. This strategy allows both the OEM and the molder--as well as other members of the manufacturing infrastructure--to bring all their core competencies together under one roof.

Try something new

Advanced process technologies will increasingly dominate the manufacturing cells of the future as a means to cut costly handling and secondary operations. Multi-material molding in all its variations will be widely used to produce cost-effective components and to support aesthetic and functional design goals. High-heat, chemically resistant, soft-touch, and aesthetic surfaces can all be achieved right in the mold without the cost and potential defects associated with secondary operations. Emerging applications for multi-material molding are as diverse as paint-free automotive components, thermoplastic connectors with silicone-rubber (LSR) gaskets, and plastic automotive glazing in a thermoplastic frame.

Gas-assist molding will likewise become more of an integral, "must-have" process than it is today. It has already demonstrated its value in diverse applications, including ones in the automotive, electronics, and appliance industries. Opportunities for improved dimensional stability, reduced part weight, improved surface finish, large-part production, functional integration, and low-pressure processing all but ensure this technique's continued growth. Add to these benefits the likelihood that legal issues surrounding the process will have been settled 10 years from now and that gas-assist capabilities will routinely be integrated into standard molding machines. Also, improvements in process simulation will put gas assist's development costs on an equal basis with standard molding. Finally, the process should get even more of a boost in the future from its potential to advance metal-replacement efforts in the automotive industry and elsewhere.

Expect to see combinations of gas-assist molding with multi-material techniques that couple the benefits of these processes and open new opportunities for plastics. For example, an automotive mirror housing can combine gas-assist molding of a glass-reinforced material for stiffness with coinjection of a high-gloss, uv-resistant material for surface aesthetics.

Because successful molders will be looking for technologies that can produce something close to a finished product in the mold, other manufacturing methods that are relatively uncommon today should take on a more prevalent role. In-mold decorating, in particular, will acquire new importance, owing to the auto industry's unwillingness or inability to expand existing paint lines. Hybrid manufacturing systems that combine compounding and molding could also become more than just a trade-show attraction, as large-part molders (of pallets, bumpers, or trash containers, for example) seek to reduce costs by buying neat resin in bulk and then adding the additive and colorant package in-line with the molding.

Other process technologies likely to grow are those that can open up new design possibilities for molded parts, enhance structural capabilities, or improve material utilization. Metal-plastic hybrid parts, such as the 1999 Ford Focus front end, meets all three goals. So does thin-wall molding.

Fewer but bigger

Due to the increased cost involved in producing assembled products, rather than just molded components, the number of injection molding companies will be significantly smaller than it is today. Product design and development, project management, and increased up-front investments for manufacturing cells simply require a level of funding not available to the small molding company.

Meeting future demands for investment capital, productivity, cost reduction, and quality will not only shrink the number of participants, it will also segregate the remaining players into tiers more rigid than those found in today's automotive world. The top tier will be well-financed "product-manufacturing companies" that have brought the product-development cycle in-house. This group will manage the development process, employ the most qualified designers and engineers, and have the most efficient manufacturing capabilities.

The next group will be less-profitable suppliers to the top tier. This group will not work directly with the OEM but with the first tier to provide molded components or sub-assemblies. This group will continue to use manufacturing techniques and processes similar to the standard ones used today.

Many of the forces shaping the molding organization of 2009 are well under way right now. Those molders who aspire to the top tier will be the ones with the vision to break out of molding's traditional boundaries. As Yogi Berra once put it, "The future ain't what it used to be."

Faster Tools Wanted

Keeping pace with the OEMs' accelerated timelines for new-product development means that tooling lead times will have to be compressed from roughly two to four months today down to as little as two to four weeks in 2009. That's especially true in the computer, personal-electronics, and consumer-products markets, which will see product life cycles as brief as six months.

One aid to reducing lead times will be the ability to capture experienced tooling engineers' knowledge in a database that becomes the basis for automating the mold-manufacturing process. A handful of emerging CAM technologies will play an important role in capturing the user's manufacturing knowledge and translating it into an appropriate machining strategy. These newer techniques include "manufacturing feature recognition" (MFR), "automatic NC" (ANC), and "knowledge-based machining" (KBM). By allowing less experienced machinists to draw on an organization's collective store of machining knowledge, these technologies will be critical to overcoming the worldwide shortage of good mold makers and to cutting lead times.

Tooling techniques based on rapid prototyping will also be used more extensively and in a larger number of applications as time pressures become more intense. Continued technical advances will likely overcome today's limitations on part size and dimensional tolerances. Similarly, these "rapid" manufacturing techniques will be capable of making anything from a few prototypes to market-introduction quantities to full-scale production volumes.

Since a job's cycle time plays such an important role in maximizing mold and machine investment and productivity, expect to see new tooling technologies that optimize cooling. These include using finite-element analysis to generate optimal mold-temperature distributions, "conformal" cooling channels that closely follow the part geometry, and mold materials with improved thermal conductivity. Early applications of these technologies indicate that cycle-time reductions exceeding 50% will be easily achievable by 2009--even though plenty of validation work remains to be done and a supply infrastructure still must be developed.

As manager of operational assets for the commercial technology group, Jack Avery decides which machines and processes will play a role at GE Plastics' Polymer Processing Development Center in Pittsfield, Mass.