New strides in plastics research and development are opening doors for advances in the production of medical parts and components. | courtesy of Kaysun Corporation
during production through cavity pressure feedback — a pressure reading of the resin as it is going into the mold. The feedback provides data on the consistency of the pressure and where correction is needed, such as a change in the viscosity of the molten material. Thus, the mold and the process must be designed to suit both the part and materials. No medical OEM would tolerate a soft-touch keypad separating from one of its handheld monitoring devices during use. Nor would they accept a waterproof seal failing because materials were improperly selected or the manufacturing process was not expertly designed.
• High-heat resins. Polysulfone and
other high-heat resins used in some medical applications and to withstand autoclaving have their own set of process considerations. These materials are more difficult — and therefore more costly — to work with, mainly due to their higher melting points, which complicate everything from safety compliance to the molding process.
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For instance, polysulfone has a melting point of 700°F compared with 500°–550°F for typical resins. Oil, rather than water, must be used to control mold cooling, requiring a longer molding process and different equipment with different risks involved. Heating oil also takes longer than heating water and metal-braided hosing must be used instead of rubber. These higher demands mean higher risks for both safety and deviation. Since the mold itself can reach 325°F (whereas a water-heated mold typically reaches 180°F), it is subject to higher levels of thermal expansion, adding complexity to the overall mold design process.
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partner’s operations, equipment, personnel, track record, culture, and financial health. A site visit should also be part of this process to assess the quality of the plant’s environment and team. DW Kaysun Corp. | kaysun.com
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Selecting a complex injection molding partner Finally, consider working with a complex injection-molding partner. The importance of selecting the right partner increases in direct proportion to the intricacy of the task at hand. The selection process should cover every aspect of a potential injection molding
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August 2018
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7/27/18 3:29 PM