Many plastics processors fail to seriously consider the importance of water management in the injection molding process.
That observation emanates from more than two decades of selling mold temperature-control and quick mold-change systems to processors, witnessing their basic carelessness with water management and getting frustrated at the unnecessary waste.
Computer technologies have made terrific contributions to the molding floor. I see intimate control of the molding machine and processing of the melt, sophisticated hot-runner systems, molds with integrated CPU's and mold temperature controllers using Windows software. Managers have eagerly embraced these important tools needed to stay competitive.
Many managers fail to understand that poor water management prohibits investments in high-tech molding machines, molds and support equipment from reaching their potential. It's like putting a governor on a high-performance race car engine; you will not win with restricted engine power.
A mold is a nonsymmetrical heat exchanger, dictated by part geometry and the cooling channel design. Cycle time is totally dependent on efficient heat removal. Therefore, poor flow equals poor heat removal, and, in turn, equals a poor cycle. A quick barometer for checking molding efficiency is to simply time the seconds from completion of the screw recovery to mold open. Divide that number by the overall cycle time to determine what percentage of the molding cycle your machine has become a very expensive cooling fixture. The target is to cycle the machine as fast as you can melt plastic. Are you aware that, on the average, 40 percent of the mold change time is just hooking up water lines?
Often during plant visits, I observe many problems in and around the water system. Almost always, the setup guys on the floor tell me that they cannot get any money in the budget to make improvements. In most cases, water management falls under the already over-taxed maintenance budget, and generally managers do not regard the water system as a serious part of the production planning process.
Managers, go take a look at your molds running in your machines now. If these molds remind you of the Mating Ritual of the South American Anaconda, you may be guilty of ignoring proper water management.
Take a serious look at the restrictions within your water systems, and make plans to correct them. The resulting improvement will be one of the best small investments you will ever make.
Paul G. Sloane is president of Technology Rx Inc. in Santa Clarita, Calif.