Injecting Progress into Molding

April 21, 2005

7 Min Read
Injecting Progress into Molding

Originally Published MPMN April 2005


Injecting Progress into Molding

New technologies and business practices generate savings

Analee Zelaya

Demag Plastics Group introduces the IntElect series with direct-drive technology. Already proven in Europe, the all-electric IM machine features NC-4 control.

Cost-effectiveness seems to be on the minds of suppliers of molding services and equipment. Whether it be where the devices are manufactured or how efficiently, molders are offering ways to save money. Saving time is also a goal for molders. While some are reducing setup and lead times, others are using innovative materials or introducing new technologies to make products more readily available.

Chinese Molder May Save OEMs Time and Money While Maintaining Standards

Quality Biomedical Manufacturing Ltd. (QMB; Fotan, Hong Kong) provides molding for North American and European medical device manufacturers. Using CGMPs in Chinese factories, QBM can mold high-performance resins on 28- to 500-tn injection molding machines. The company has also produced millions of parts using other materials such as rigid and flexible PVC, polycarbonate, ABS, polypropylene, and Kraton thermoplastic rubber. Labeling of components using engraving, hot stamping, and pad printing is also offered, along with insert molds that use metals and plastics.

QBM is currently installing a new 1500-sq-ft Class 10,000 cleanroom in its Lung Wah, Hong Kong factory, which was scheduled to be completed and certified in the first quarter of 2005. This facility will be used exclusively for medical device assembly. The firm is also considering a joint venture for molding silicone medical devices in a separate Class 100,000 cleanroom on the same floor.

According to company president Sean Lundy, potential customers who question the ability of China-based subcontractors to meet the standards of medical device OEMs should rest at ease. He points out that factories in China have a long history of ISO and GMP compliance. “I have found that it is not usually the standards of the Chinese factories that are lacking, but the knowledge of such compliance amongst Western medical device manufacturers,” he says. “It is rare that prospective customers have any quality concerns after they visit our factories for a quality audit. However, in such an instance, I might suggest that they first try out QBM with a project where quality issues are minimized, but where the economic value of China outsourcing can be maximized.” Lundy maintains that an export-tooling project might be the right fit in this case. He adds that an equivalent injection molding tool in the United States might be three to eight times more costly than QBM’s, and that his company can often deliver its products in half the time of a U.S. vendor.

Unlimited turns are possible with the CNC servomotor-controlled core from B A Die Mold.

QBM offers 300% inspection, meaning that every molded part is inspected by three people, to ensure quality. The company has no minimum run-size requirements.

Small, Quiet Machine Makes Noise in Injection Molding

A direct-drive molding technology is available in 55- to 165-tn all-electric injection molding machines. According to Demag Plastics Group (Strongville, OH), these units are quicker, cleaner, and more precise than its 220- to 385-tn versions that feature the traditional belt-drive molding technology. The company gives molders in the medical industry both options through its IntElect series of injection molding machines. They are often used in liquid silicone molding because of their high degree of accuracy in controlling the position of the screw.

“While [it is] new to North America, our European operations have been building and selling IntElects with direct-drive technology since [early in 2004],” says Tim Glassburn, IntElect series product manager. “The direct-drive technology has already proven itself in real-world applications and in tests since we first exhibited it as a prototype in 2003.”

The all-electric belt-drive technology is most commonly used today. It offers maintenance and productivity benefits compared with its hydraulic counterparts in certain applications. However, it requires gear trains for rotary and translatory movements of the machines. While quieter, cleaner, and more efficient and precise, the equipment tends to be more costly than hydraulic systems because of its high-speed, low-torque motors combined with reduction gearing.

Incorporating synchronous, high-torque, water-cooled direct drives, Demag’s smaller-tonnage IntElect models do not rely on reduction gears and mechanical transmission components. Instead, direct-drive technology calls for only a few parts, resulting in reduced maintenance time and costs.

The IntElect series uses NC-4 control, the firm’s global machine control system. A high-torque motor on the end plate powers the opening and closing movements of the direct-drive IntElect mold. The motor transmits rotation using a ball screw to the toggle system, which induces the axial movement of the moving platen. Rapid response and precise mold movement, resulting from the accuracy and short reaction time of the motor, are the advantages of the toggle clamp.

Useful Prototype Accelerates Transition to Production

Stockwell Rubber Co. fabricates and molds silicone rubber components.

A company, specializing in injection molding has automated and standardized its entire injection molding process. Prototype Plus, a rapid tooling system from J&L Plastic Molding (Wallingford, CT), offers design engineers or product developers a way to test new injection-molded parts, and then transition into production.

“Customers can get their parts with any grade of material, and run production off those tools as well,” says Marty Kellaher, the company’s vice president of marketing. “They don’t need a prototype, then a secondary tool.”

Kellaher explains that some companies use aluminum or cast molds, the output of which cannot satisfy production needs. However, J&L machines everything soft in S-7 steel. Then, once the part is approved, the steel is hardened. Production-type numbers are then possible.

The system accelerates time to market, because it combines CAD/CAM, automation, and craftsmanship. Once the customer gives J&L a CAD file, the firm can be cutting steel within hours, since it fabricates and maintains all the mold components it needs. J&L has also created a whole framing system. This saves money for customers by eliminating the need to buy a frame or do lead work.

Typical lead time is 3 weeks or less when parts require high-speed CNC machining. Electrical-discharge machining (EDM) technology may be employed to achieve desired finishes and intricate shapes. Up-and-down part to 90° side-action designs are accommodated.

Additionally, customers end up owning their mold components. As a result, if at any time they want to transition to traditional framing, they can do so.

Company Strives for Core Positioning

A patent is pending on a CNC servomotor-controlled core that offers accurate, fast, and efficient core positioning with unlimited turns and programmable speed profiles. Ideal for electric molding machines, the PERC System is offered by B A Die Mold (Aurora, IL). The firm designs and builds molds for clear and optical parts, as well as close-tolerance internal and external threaded applications.

Molding Performed On-Site

ISO 9001:2000–certified Stockwell Rubber Co. (Philadelphia) offers in-house compression, injection, and custom molding. The company’s main focus is providing die-cut, fabricated, and custom-molded components in silicone rubber and similar high-performance elastomers. These components are most often specified to meet requirements such as special ESD and EMI shielding in high-technology OEM equipment designs.

The firm employs lean business practices to reduce setup costs. This provides unit cost reductions in curtailed production runs and shortens lead time.

Copyright ©2005 Medical Product Manufacturing News

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