How to mold with 0 PPM quality

Medical Design Article, December 1, 2007

Like any other medical manufacturing process, plastic injection molding must hold to rigorous standards of cleanliness and accuracy. Our company uses what we call the special “Scientific Manufacturing Assures Reliable Throughput” or Smart method. A conventional use of scientific molding rarely goes beyond cavity-pressure monitoring. Smart, on the other hand, considers this and all other aspects of injection-molding as well as secondary operations to develop a well defined, controlled manufacturing process.

Besides customer requirements, the method considers product development from design through manufacturing and from the point of view of the plastic pellet. The method includes three essential areas: environment, equipment, and employee education.

For example, Smart works to control every stage of the environment surrounding the resin. This might entail, for example, controlling flow, humidity, and temperature. And the facility has a predictive-maintenance program in place to anticipate repairs and reduce the risk of equipment failure. These safeguards reduce variation in manufacturing for maximum throughput.

The method also considers each piece of equipment the plastic pellet encounters, before, during, and after processing. It specifies comprehensive standards for handling, data input, visual management, and inspection for reliable plastic processing.

Component tooling plays an especially critical role for equipment. Each mold is carefully designed, using software for prototyping, solid modeling, and mold-flow analysis. Molds are built with collaboration among tool builders, project managers, and the production floor.

Last, and perhaps most importantly — employee education. Employees are trained and certified by internal and external verifiers on the widely recognized Global Standards of Plastics Certification program. Following the Smart method requires a complete cultural investment. But the effort is well worth results. These include 0 PPM quality levels, and consistent just-in-time delivery.

The three articles in this section provide a varied perspective on the rapidly developing landscape of injection molding. The first tells how to find a molder capable of manufacturing parts smaller than a 0.5 in3. The second discusses how monitoring more than cavity pressure improves dimensions and tolerances, and the last assists with transitioning a critical part from one mold shop to another.