New Tech Drivers

Advanced molding technologies create more options for keepingOEMs satisfied.

Mark Crawford • Contributing Writer

Molders have a lot to think about. With fierce global competition, there is always the risk of losing work, especially if they can’t keep up with the demands of their customers. U.S. Food and Drug Administration (FDA) scrutiny has led to increased quality certifications and up-front quality and design requirements, such as process failure modes and effects analysis and control plans. Then there is the desire by OEMs for tighter tolerances and smaller components, as well as reducing part counts and keeping costs down. Increasing numbers of OEMs are requesting their molders to perform destructive and dynamic-use testing as part of their ongoing quality plans, as well as expecting them to be the compliance sheriff for their section of the supply chain—even when the suppliers are specified by the device manufacturer. Pre-outlined disaster recovery plans that describe plans of action and timelines to start running production after a disaster strikes also are being requested by OEMs—no small task.

Then there is the technical side. Most new applications are more involved than standard conventional molding. Specializations range from being as simple as adding a post assembly and packaging work cell to merging new technologies and electronics in molding and assembly. OEMs want smaller and more complex parts, often built from new materials that are more challenging to mold. With parts that are smaller than a grain of rice, tolerances become absolutely critical.

With myriad expectations to fulfill, contract manufacturers must have a thorough understanding of all aspects of the devices they produce, not just the molded components. Integrating an electronic component, for example, isn’t as simple as placing the circuit board into the device.

“Issues such as containment of the electronics, stack-up tolerances, electrostatic discharge protection, and proper handling and assembly methods all need to be taken into consideration up-front for success of the product,” said Asmita Khanolkar, senior program manager for SMC Ltd. in Somerset, Wis., a provider of global contract manufacturing and molding services for the medical device and pharmaceutical industries. “As OEMs demand more from their suppliers, there is greater need to be prepared to learn, merge, and marry various technologies. Knowledge of medical applications, and experience in automation and specialized work cells, help integrate the various science fields into successful implementation.”

Quality and Compliance

Staying on top of all these demands in a smooth and integrated way can be daunting. Risk analysis, management, and control are three ways to generate solid, error-free procedures—especially as process complexity continues to grow. Sound validation methods and engineering studies are essential for establishing robust processes for device production. Further, OEMs are expecting this kind of proactive support from their suppliers through all phases of the production process.

At each stage of the project, testing and validation are required for mold build, molding, and assembly validations. Molding tolerances are getting increasingly tight, with +/-0.001 inches not being unusual anymore. This kind of high precision especially is challenging with high-cavitation molds that must meet specific Six Sigma capabilities. Simply the variation of resin viscosity within the lot can cause a drift in tolerance. Therefore it is important for manufacturers to identify the mold, machine resin, and process normal variation and try to minimize it as much as possible.

Performing risk analysis, both for the customer and the manufacturing process, in the earliest stages will help identify key molding parameters. For example, are the specifications well defined? Are the validations streamlined? Are the contracts in place?

It is essential to integrate the contract manufacturer’s risk analysis with the failure modes of the actual device provided by the OEM.

“Many people overlook this, since each company has its own ratings and risk procedures to follow,” said Khanolkar. “It is viewed as more of a procedural step. What could be a high-risk item formanufacturing for the contract manufacturer may not necessarily be a high-risk item for the device and vice versa. Thus, it is important to understand the device first and how it could fail, then marry that with the possible failure modes in manufacturing and risks.”

These results will change the direction of manufacturing. For example, in trying to manufacture a device for blood collection or to grow cells, the biggest risk factor is possible contamination and bioburden. Thus, the first thing the contract manufacturer needs to study is minimal handling and automation in a clean room.

“Cosmetic molding defects may not be a huge risk to the device,” added Khanolkar. “This changes the direction and risk ranking completely for manufacturing. Another example is surgical handles—any molding defect on the surface is a big factor, such as a sharp gate vestige that can rip the clinician’s glove.”

With the FDA’s changes to device validation rules, OEMs now are requiring more vendor validation. One of the biggest changes is that prototype tooling no longer is used to produce product for testing. Under old 510(k) guidelines, a medical device could be approved without any clinical data. Medical device companies were more concerned with quick prototypes to show functionality. 510(k)s were submitted and production design and implementation would follow.

Now, however, “medical device companies are faced with a longer approval process and need to provide clinical data,” said Steve Raiken, president of RENY, a Baldwin Park, Calif.-based plastic injection molder, mold designer, and fabricator. “Most device companies are recognizing that products built by less than a production method are susceptible to more clinical variation that could impact the approval process. More of our customers are requiring validated production tooling prior to clinical trials, whereas in the past this was only seen with products applying for a premarket approval (PMA).”

Increased validation costs and their impact on project lead times continue to be a growing hurdle. Even so, more medical customers are embracing the Installation Qualification, Operational Qualification and Performance Qualification (IQ, OQ, and PQ) validation process. Only five years ago such validation protocols were relatively uncommon; today they are being used by established medical OEMs as well as start-up companies.

“The biggest impact this has on tooling is the need for higher tolerance on the molds,” said Mark Fuhrman, director of sales and marketing at C&J Industries, a thermoplastic injection molder in Meadville, Pa., that produces component parts and complete medical devices. “On the molding side, the OQ portion stresses the process limits to determine the optimum process. The PQ portions then stress the optimum process over longer trial runs. In the past, a 32-piece capability study was often adequate to prove the production worthiness of a mold; that is now only a small portion of the overall validation process.”

Although these validations take more time and cost more money, overall it gives both the supplier and customer a much higher degree of confidence in the quality of the end product.

Kevin Allison is business development manager for Crescent Industries Inc.’s medical molding division, a provider of various custom molding processes for the medical device industry based in New Freedom, Pa. He indicates that upfront process development and validation using scientific and decoupled molding principles are good ways to bring consistency and repeatability to production. An example of this approach is a recent Crescent Industries project that required a piece of stainless steel hypo tubing and a pre-molded component that gets over-molded at three locations.

“We decided to run the parts on a vertical/vertical rotary table injection molding machine with a mold design that consists of two bottom halves that are two cavities each,” explained Allison. “One hot half is sequential valve gate controlled. The valve gates are controlled separately for each bottom half via an in-mold cavity pressure sensor for each detail. The advantage to this process is the plastic volume control gained with the sequential valve gates, material viscosity variation control using the cavity pressure sensors for individual valve gate closure, and a consistent robust process capable of producing higher quality parts, lower scrap rate, and less machine hours. The gate quality issues were eliminated with the control and monitoring capabilities of the sequential valve-gate system. The customer was satisfied with the improvedquality of parts and the mold continues to produce outstanding components today.”

Of course, process development and validation can be optimized using today’s mold simulation software. Simulation software predicts process simulation and optimization of gating locations, all which affect the quality of parts.

“This uses actual data for decision-making in the mold building process, not just an opinion,” Allison told MedicalProduct Outsourcing. “The more scientific upfront engineering work before the tool is built, the fewer tooling adjustments after the tool is completed—which means the project gets turned around more quickly.”

Molding Technologies

Injection molding is a standard molding technology in the medical device market that produces parts from both thermoplastic and thermosetting plastic materials.

“New advances in injection molding give contract manufacturers better control, less waste, and faster cycle times, as well as the ability to make smaller parts with more difficult features,” said Thom Murphy, director of business development for Vaupell Molding & Tooling Inc. in Hudson, N.H., an injection molder of engineered resins and implantable grade materials. “Thechallenge, however, is that we also have to invest in the capability to make the tools (injection molds) and be able to inspect the parts to maintain high quality.”

Different types of injection molding also can be combined to create unique parts and products. Raumedic AG, a German provider of components and systems for the medical device market with a sales office in Leesburg, Va., recently added “sandwich injection molding” to its molding services, a process that combines multiple thermoplastic materials injection molded into the same part. This molding procedure can enhance performance properties such as functional, tactile, or design features. The ability to combine rigid and flexible materials through sandwich injectionmolding, for example, can create a final product with a wide range of possible applications, such as barrier functions to prevent out-gassing of drugs or permeation.

“Multi-component injection molding allows us to combine various thermoplastic materials and harness their unique properties in combination to create customer-specific, innovative products,” said Richard DiIorio Jr., technical sales manager for Raumedic, Northeast USA. “Other benefits are the cost-effective assembly of individual components and the integration of our extrusion and molding capabilities assembled together into the one final device.”

Metal Injection Molding

As the medical industry faces increasing concerns about the price and quality of devices and instruments, more suppliers areturning to metal injection molding (MIM) to improve quality and reduce costs. Biopsy jaws, endoscopic instruments, bone screws, drills, and other instruments now are being produced with the MIM process.

“Femoral and tibial implants are produced with little or no secondary machining, resulting in a savings of 25 to 40 percent over castings, while improving part performance,” said David Smith, senior sales manager for Advanced Forming Technology, a metal injection molding company in Longmont, Colo., that produces implants, instruments bone drills and tibial and femoral F-75 knees.

MIM is an effective way to produce complex and precision-shaped parts from a variety of materials, with repeatable tolerances as low as ± 0.5 percent. The MIM process is a combination of plastic injection molding and powder metal. The first step is compounding, where fine metal powders are mixed with plastic and pelletized. The blend is approximately 60 percent metal and 40 percent plastic. This material then is placed in a standard plastic injection molding machine and processed. The resulting part is about 20 percent larger than its final size and ready for debinding.

“Using heat and/or chemicals, most of the binders are removed from the part at this time,” said Smith. “The component is then placed in a vacuum furnace for the final operation of sintering. The remaining binders are removed and the part shrinks about 20 percent to its final size, resulting in a high density, complex-shaped component.”

MIM is attractive to medical device manufacturers because it creates parts of very intricate geometry with tight, repeatable tolerances. “The very same part is not feasible to be machined at volume and is well outside the scope of other processes,” added Smith. “MIM has become another solid option that we offer to our clients.”

Micro-Molding

Over the years, micro-molding has become a go-to solution for companies that are expected to produce, with high-precision, parts that weigh 0.001 grams or less and are 0.075 inches in diameter or smaller.

“However,” cautioned Scott Herbert, president of Rapidwerks Inc. in Pleasanton, Calif., a micro-molder serving the medical device and orthopedic implant industries, “some companies in the industry have a faulty assumption that normal everyday injection molding machines can mold micro-parts. You simply cannot apply the same principles of injection molding for regular-sized parts to injection molding for micro-sized parts.”

Even micro-molding and small-part molding are very different (a small part might weigh 0.1 to 1.5 grams with a diameter of 0.25 inches or larger). Micro-parts require specialized machines for molding, specialized tooling, and custom part handling for part extraction and part packaging. Micro-molding also works well with engineered materials, including resorbables.

“The ability to micro-mold small parts out of implant materials cost-effectively, and to be able to save money long term by converting conventional molding to micro-molding, can lead to material savings worth millions of dollars,” said Herbert. “For example, injection-molding a micro part out of polyetheretherketone (PEEK) requires a hot runner tool, a $65,000, 40-ton injection molding machine, and there are problems with short shots, flashed parts, sink, and material degradation. Micro-tooling on a $26,400, five-ton micro-molding machine saves enough PEEK over one year to pay for the new tooling.”

The Advantages of Automation

The use of automation in the injection molding process has a number of advantages: It provides consistency, higher throughput and lower part cost, and faster inspections. By reducing errors and improving speed, automation leads to lower operational costs and greater customer satisfaction.

To offset low labor rates, automation and smart manufacturing is a must. Not everyone can automate and it requires both a huge initial investment and skilled talent to use the automation and maintain it. “The SMC culture is technical so this comes naturally to SMC,” said Khanolkar. “We have many such automated cells. One of these cells, for example, is saving us more than $100,000 per year. We have coupled two injection molding presses with automated assembly. Presses run simultaneously and the parts are transported through enclosed conveyors, ultrasonically bonded, and assembled in-line. All manufacturing takes place in Class 7 clean rooms. The savings come from no assembly labor, minimal handling, eliminating dual packaging, and streamlining production loading.”

Automation is a continuing quest for molding firms.

“The automation process is a long-term investment both to our customers and to our future,” said Fuhrman. “We have nearly eliminated direct labor from many of our high-volume, medical component parts.”

The entry cost to invest in automation can be quite high at first. Typically companies have two choices: outsource or hire talent and bring it in-house. There are steep learning curves on both sides. Outsourcing can lead to unexpected costs and longer lead times. Doing automation in-house often will result in more control, but not necessarily immediate results.

C&J’s responsiveness to these trends has resulted in some fairly dramatic growth. The company has grown over 25 percent so far in 2011—most of which can be attributed to sales in the medical device market. C&J is in the middle of $6 million expansion that will increase its overall clean room capacity in excess of 50 percent.

Impressive growth is, however, not without challenges.

“It’s been tough to find the type of talent we need to support our internal needs,” added Fuhrman. “Fortunately C&J Industries is located near both Penn State Behrend—they have an excellent plastics engineering program—as well as to Precision Manufacturing Institute (PMI). PMI is a local company that provides a degree training program for a wide host of manufacturing processes—including ‘Mechatronics.’ Developing relationships with organizations like these is a good way to connect with the best local talent, as well as stay on top of new developments in the industry.”

Mark Crawford is a full-time freelance business and marketing/communications writer based in Madison, Wis. His clients range from startups to global manufacturing leaders such as Kohler. He also writes a variety of feature articles for regional and national publications and is the author of five books. Contact him at mark.crawford@charter.net.