OEM engineers and designers get to do the easy part—they say, “This is what we want.” Or, “It needs to be smaller.” Or, “We want it made from this instead.” Molders have the hard part—they need to know the latest technologies, the most up-to-date material science and the best processes to make it all happen—and happen quickly (“By the way, we’d like that first prototype in about two weeks.”). No pressure, right?

Then there are the heightened regulatory controls to worry about—OEMs want to spread the risk by making vendors as responsible for meeting compliance standards as they are (or sometimes more so). These expectations have increased the need for better controls and documentation by the molder, especially as medical devices become smaller and more complex.

Every vendor knows that OEMs are shortening their supply chains, looking for partners who can do more and function as “one-stop shops” to provide multiple services. This, of course, makes everything move faster, including communication and decision-making. Molding processes that are in higher demand are overmolding, insert molding and multi-component molding—these improve product functionality by combining the properties of multiple polymers (both hard and soft).

“For example, medical device designers are using two-shot injection molding to move beyond soft touch and aesthetic features, by using the different materials for mechanical functions,” said Jay Smith, chief of operations for Classic Industries Inc., a Latrobe, Pa.-based provider of injection-molded products.

Medical device companies are putting an even higher premium on cost reduction and overall cost consciousness—another reason these molding technologies are gaining in popularity.

Two-component, injection-molded parts. Photo courtesy of Raumedic.

“The market is demanding that injecting-molding companies offer molding solutions that can eliminate established assembly processes, thus reducing cost and offering a more robust product solution,” said Tom Moore, technical sales manager for Leesburg, Va.-based Raumedic, a developer and manufacturer of polymer and silicone components via extrusion, injection molding and assembly. “From the purchasing side, the cost advantage is the elimination of labor-intensive assembly steps such as solvent or UV bonding. These molding techniques result in higher-performing products and also reduce the number of steps needed to make them, which improves quality.”

As products get smaller with tighter tolerances, OEMs look for vendors that are committed to using automated assembly techniques to combine multiple components, reducing labor costs and increasing quality. This, in part, is due to increased interest in bringing outsourced work back from Asia—especially for more complex parts made from multiple materials, where the risks for quality problems are much higher overseas.

“Quality control tends to be inferior in many overseas manufacturing settings, which can neutralize the savings in labor costs,” said Smith. “Also, because of the highly sensitive timeframes required for the turnaround of many of these deliverables, timely shipping from outside of theU.S.can be an issue. Automation, with its faster production speeds, can counteract the higher labor costs in America—combine that with the higher quality delivered by automation and the U.S. can be cost-competitive with Asia.”

High-speed automation is definitely in high demand and has made significant advances over the last few years—for example, automation and injection molding press cycle times have been greatly reduced. Not only will companies that embrace automation secure their place in the OEM supply chain, they will be much more competitive in the global economy.

“Yushin and Staubi produce some very impressive robotic systems,” said David Lennox, vice president of operations for C&J Industries, a custom injection molder and contract manufacturer based in Meadville, Pa. “We currently use Yushin robots on our presses and are expanding our usage of these systems to not only pick product from the molds, but to stage or load into secondary processes, eliminating human intervention. We are also considering robotics for off-line operations. We are always investigating equipment that is flexible in our custom operations to perform the repetitive operations.”

The Speed of Innovation
OEMs want their medical devices to satisfy the needs of their end users: improved patient outcomes, reduced hospital stays and improved recycling of disposable medical products—which are all opportunities for OEMs and their supply chains to develop more innovative products.

“The trend toward creating better patient outcomes has sharpened the focus on the engineering of plastics resins to help products and devices function better,” said Smith. “The medical industry wants smart polymers that help products function better, and they also want products and materials that help counter healthcare-acquired infections.”

OEMs are outsourcing much of this innovation (including material science, molding technology and assembly) to their manufacturing partners. However, as more control is enforced by the U.S. Food and Drug Administration (FDA), cost structures continue to increase and product margins erode.

“As a result, more emphasis is being placed on new market development and products to meet these evolving needs,” said Mike Nowaczyk, vice president of operations at SMC Ltd., acontract manufacturing and molding company in Somerset, Wis. “The old engineering methods and standards need to change, because the cost of the product will not support the value proposition for the OEM or consumer. OEMs must continue to evaluate their own manufacturing portfolio and outsource accordingly to maintain shareholder value.”

One way to bring costs down is by using better process controls. After many discussions with customers and potential customers, Raumedic discovered that one of the highest priorities for its clients was more inline process monitoring.

“The feedback we have received is 1) inline process monitoring increases the quality of the product as the molding process is being checked and dimensions are verified inline, and 2) a cost reduction is often seen as many companies complete a 100 percent inspection due to the criticality of the product,” said Moore. “If in-line controls can be incorporated that identify critical dimensions and features, the customer can eliminate the incoming inspection and achieve an overall cost reduction, sometimes as high as 30 percent.”

Raumedic uses specially designed in-line vision systems to confirm a product maintains critical dimensions.

“Our vision systems depend on the products and their key features,” Moore explained. “For some products the vision system will check filling the part (no short shots), dimensions and inspection for imbedded particles. The tolerance range is about +/- 0.002 inches.For short-shot and air-gap control, we utilize special pressure/temperature transducers that allow 100 percent in-line control of pressure and temperature within a qualified and validated process window.”

Molded pharmaceutical drug delivery plugs undergoing a laser inspection test. Photo courtesy of C&J Industries.

Vision systems also can be used to monitor part ejection—a critical step in achieving and maintaining a successful manufacturing process.

“The smaller the components, the more difficult detection becomes as they are ejecting from the mold,” stated Dan Tasseff, director of sales and marketing for Flomet, a Deland, Fla.-based custom manufacturer of metal injection molded components.“Vision systems play a major role in assuring that molds are not damaged due to a defective ejection of material.”

Technologies at the Forefront
The trend toward smaller components has a significant impact on various methods of molding and their capabilities, including metal injection molding. The feedstock is a custom blend of polymer and powder metals, where the formulation and particle size is critical to the moldability of the component. The process also requires precise process controls for the molding parameters to achieve the complex geometries of each component.

“For example, thinner walls and tighter tolerances are in higher demand,” said Tasseff. “We can mold components with wall thicknesses of .005 to .020 inches (the lower limit for many companies is about .040 inches). Thin walls are especially critical in package configurations where the inside of the package houses a number of miniature sub-assemblies.”

Conventional metal tools usually take four to six weeks to produce, but with stereolithography (SL) the complete process from computer-assisted design to fitted injection molds can be completed in eight working days. “As a result, costs and time to market are substantially reduced,” said Smith. “Tooling produced on SL systems also offers a number of key technical advantages, including more ways to build complex geometries and tight tolerances.”

A recent emphasis in tooling technologies is thermal management. Increasingly complex applications and molding processes require greater innovation in applying heating and cooling technologies to mold design. Traditional heating and cooling is done with either water or oil; cooling lines are created by drilling intersecting straight holes in the mold. Drilling straight holes limits where cooling lines can be placed—the biggest drawback to traditional cooling methods. The water or oil temperature must be controlled with a thermolator to maintain constant temperature as the mold runs and absorbs more heat from the cooling plastic.

In conventional molding, Phillips-Medisize, a provider of injection molding, silicone molding and extrusion based in Hudson, Wis., increasingly has leveraged the use of conformal cooling with additive construction of critical mold components. This technique allows for the manufacture of small, complex geometry cooling circuits that are not possible with computer numerical control or electronic drafting machine machining.

“We have been able to solve sink and other appearance issues with this approach,” said Bill Welch, chief technology officer for Phillips-Medisize. “Benefits include better dimensional accuracy and faster cycle times. For example, cycle time with a standard one-cavity is 16.78 seconds; with a conformally cooled four-cavity mold the cycle time is 13.02 seconds, a 22.4 percent improvement.”

Another cooling innovation is CO2 spot cooling. Phillips-Medisize uses this innovative technology to solve unique cooling issues, such as molding products that present long, thin core geometries.

“Usually core pins in the mold are too small to accommodate H2O cooling,” said Welch. “In addition, the thermal expansion of the coring has to be controlled to avoid breaking the tip of a pin while maintaining a shutoff. The coring forms a .007-inch hole in the part. This part cannot be conventionally molded without the use of CO2 spot cooling. CO2 spot cooling can also be used as a substitute for water when specific areas (hot spots) need cooling. The liquid CO2 flows in through capillary tubes then expands in cooling channels, creating a snow and gas mixture with a temperature of -79°C. After removing heat the CO2 is exhausted to atmosphere. The use of CO2 spot cooling can reduce surface defects, warpage and long cooling times.”

Another innovative process is multi-component injection molding, where hard and soft thermoplastic polymers are combined in one product without post-assembly.

“This is especially effective for applications such as sealing and connecting combinations of different thermoplastics,” said Moore. “The soft component reacts chemically with the hard component and can only be separated through destructive force.”

Raumedic has developed a unique process for piracy protection (anti-counterfeiting).The technology is the addition of micro-particles during the molding process.The incorporated micro-particles provide every product with a customer-specific fingerprint that is undetectable without special equipment.

“The sandwich-type-designed micro-particles can be as small as 5 microns and enable a targeted, adjustable color coding with billions of possible combinations,” Moore noted.“The use of special readers or suitable microscopes makes it possible to quickly and reliably verify whether a product is an original in-house product, or the result of a product piracy.”

Kaysun Corporation, a provider of critical molding applications for medical, industrial and consumer markets based in Manitowoc, Wis., incorporates in-mold labeling to imbed graphics into the plastic being molded—an effective solution when graphics on the device degrade from cleaning, or wear and tear.

“Graphics are printed onto a thin film and then placed into the mold,” said Mario Del Real, sales engineer for Kaysun. “When the plastic is shot into the mold the graphics are imbedded on the backside of the plastic. It takes some skill to perfect the right technique. Methods for holding the film in place prior to molding include applying an electrostatic charge or a vacuum. In-mold labeling can be a cost-effective way to add graphics to a part and eliminate the concern of the graphics wiping off or getting scratched. It also eliminates an assembly step.”

A Complex Challenge
The trend toward more complex, miniaturized devices continues to challenge molding technologies. Component designs are becoming more complex as OEMs take advantage of different types of injection molding to reduce the number of parts in an assembly (and the number of steps).

“Today’s demand is for smaller components for non-invasive procedures,” said Tasseff. “A large percentage of what we are seeing in the market is similar components in design and capability—graspers, cups, end effectors, for example—but with smaller overall dimensions, which translates to tighter tolerances, thinner walls and more complex and precise features.”

There is increased demand for micro-sized parts with more capabilities, especially in the spine, orthopedic, arthroscopic, cardiovascular, dental and neurologic markets. Such demand is creating new molding challenges.

“Controlling the shot size is very critical,” said Scott Herbert, president of Rapidwerks Inc., a precision injection molding and micromolding provider based in Pleasanton, Calif. “It is also not that easy to create a tool that produces such a small, detailed part.”

Micromolding requires advanced equipment, new tooling capability and more controlled science regarding material and material preparation.

“For example, creating a part that is implanted in the body, such as a bone screw, requires intricate detailed complex tooling to create the correct geometry (the lead),” continued Herbert. “The material needs to be prepared in such a way that the process of manufacturing does not degrade the material or create problems with the dimensions.”

As medical devices get smaller and more complex with tighter tolerances, designers sometimes turn to more exotic materials, such as PEEK (polyetheretherketone). Although it is more expensive and presents molding challenges, its unique properties continue to draw interest throughout the medical device community.

“C&J recently completed a metal-to-plastic conversion for a large surgical device project,” said Mark Fuhrman, director of sales and marketing for C&J Industries. “Even though using PEEK was extremely expensive, the injection molding process enabled our customer to integrate features into the components that eliminated machining and, in some cases, reduced the number of component parts. This ultimately gave the customer a double-digit cost reduction with a better-than-expected return on investment. PEEK provided the mechanical and heat properties required for the metal-to-plastic replacement. In some instances the metal parts were weldments that required machining and anodizing—our customer was able to avoid all three steps with the molded part alternative.”

Increased requests by OEMs for the use of high-cavitation molds and automation continue to stretch the limits of the injection molding process. The ability to build and support automated parts handling and inspection equipment is a necessity—they require 24-7 technical support.

“The challenges of higher-cavitation molds are numerous,” said Lennox. “When a company like C&J moves from a typical molding operation of 4-8 cavities to 32 and 64 cavities, every process in our manufacturing environment has to change with it. Inspection processes have to be compressed and water delivery systems need more capacity.”

The cost of producing bad product increases dramatically when you move to 32 and 64 cavity molds, Lennox added. “Everything you do must be right and checked and verified it’s correct the first time to insure zero defects.”

A Glimpse of the Future
Medical device companies are approaching cost-reduction process by shortening their supply chains and contracting with vendors/partners that provide multiple manufacturing techniques and processes, materials, development capabilities and deep all-around expertise.Molding companies will continue to be challenged by working with new advanced compounds including biomaterials, anti-microbial formulations, new co-polymers (for example, silicone/polyurethane with increased silicone content) and new silicones (UV-cured silicone).

“The medical industry is shifting toward suppliers with multiple manufacturing capabilities that use automated assembly techniques to combine multiple components in an effort to improve functionality and reduce costs,” said Moore.

According to Tasseff, metal injection molders that can adapt to the changes in the market quickly and efficiently will prove to be the leaders in the industry.

“Success and growth will be achieved by being recognized as a solutions provider that has ability to meet the demand in various markets through the development of new and exciting capabilities—thin walls, smaller and highly complex components, etc.,” he said.

With the rising costs of overseas manufacturing, longer lead times and quality concerns, the cost to manufacture overseas is starting to lose its advantage.

“Some companies are looking to bring business back from Asia because of the increasing costs in China, quality concerns and costs to ship,” said Del Real. “Competitive manufacturing in the U.S. is starting to take hold again and we are seeing this trend in several markets.When you take the entire cost into account, the cost difference may not be great enough to risk, especially on new program launches.”

Faster time to market is a strong theme for 2012 and certainly will affect manufacturing in the future. OEMs are challenging molding suppliers with unprecedented timing requirements to deliver prototype samples and to be production-ready.

“This challenge is enhanced as we see many large OEMs farming out new product development projects to design firms,” Moore explained.“Many of these design firms are looking for quick turnaround times (1-2 weeks) to have parts to check for functionality.In many cases, these ‘development projects’ do not yet have funding and therefore, the molding company is not only expected to react quickly, but also absorb costs in the start-up phase with no guarantee that the product will be embraced by the OEM.”

Overall, the industry has not fully embraced technologies that can streamline production validation, which also speeds time to market, experts noted.

“Over the past 20 years the industry has evolved immensely,” noted Smith. “However, there are complex challenges with regulations. Gaining [FDA] 510(k) approvals is becoming a difficult task, and is driving companies away from theU.S.market. The industry is troubled with the difficult economic environment and very few venture capitalists are investing in early stage opportunities. It is a tough environment and medical device executives must spend time trying to improve R&D, launch and commercialization processes.”

Even with capital investment in the latest technology, speed to market remains hampered by longer FDA approval times. The agency has increased scrutiny of the medical device industry, which directly impacts molding suppliers. OEMs are pressuring vendors to be sure components meet very strict risk-analysis requirements.

“More upfront planning and engagement of the contract manufacturers earlier in the design phase will reduce the chances of unattended product and process failures in the product realization process,” said Smith. “Identification of critical design features and failure modes that are supported by in-process investments, and that reduce risk for the OEM, is a crucial piece of the product realization process.”

Mark Crawford is a full-time freelance business and marketing/communications writer based in Madison, Wis. He can be reached at mark.crawford@charter.net.