Cleanrooms are fast becoming a necessity for molders of medical products who must effectively address the many quality and contamination concerns associated with producing medical plastics.

There was a time when systems designed for cleanroom environments significantly restricted efficiency and capabilities. However, new advancements in technology are giving molders cleaner, faster, more powerful, and more efficient options.

This article will examine two specific cleanroom advancements: all-electric injection molding machines and electric valve gate hot runner systems.

Clean efficiency Hydraulic injection molding systems provide numerous benefits to molders. Unfortunately, the risk of oil leaks and contamination makes them unsuitable for use in cleanrooms.

All-electric systems provide a much better solution. These types of systems have been growing in popularity not only because they're cleanroom compatible, but also because they use dramatically less energy. Machines such as the Roboshot and PowerPAK lines from Milacron reduce energy consumption by 50% to 80% with repeatable and precise cycles that are 5% to 50% faster than hydraulic machines.

All-electric injection molding machines offer other benefits as well.

Accuracy, repeatability, and consistency. Electric machines are digitally controlled and mechanically driven. Their processes do not vary over time since they have no hoses to expand, no valves to potentially stick and no hydraulic fluid to heat up or compress. Molders often report that these machines produce good parts by the third or fourth shot and then run without attention until it's time for a mold change.

Higher part quality. Electric machines turn injection molding into a more predictable operation. With a more consistent machine, the same process setup can be used repeatedly, without affecting part consistency or quality. For example, screw position for fill and pack is controlled with digital precision, eliminating overpacking and greatly reducing molded-in stress. Consistent machine performance also allows labor cost reductions with unmanned shifts at night or on weekends. Utilization of skilled labor is greatly enhanced.

Lower cost per part. From the day the machine starts up, it reduces cost per part. All-electric machines produce faster cycle times because of independent clamp/injection functions. Their precision shot control saves material and prevents using more resin, colorant or additive than the part needs. Electric machines let processors mold closer to the threshold of just-the-right-amount of material, without falling below it.

Lower operating costs. Whether small or large, all-electric machines dramatically reduce operating costs, using 50% to 80% less power than equivalent hydraulic machines. Connected power requirements for an electric machine are only 25 percent of those of a hydraulic machine.

Speed and precision

Hot runners have long made processing more efficient and cost effective while improving part quality. However, in cleanroom applications, those benefits have been offset by the need to use pneumatic hot runners with slower response times and weaker closing forces.

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