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it's a good idea to regularly replace a percentage of the water. •Environmental issues. Ambient conditions can also affect the way an injection mold and associated heat-transfer equipment perform. Hot, humid summer weather can burden your heattransfer system by adding to the heat load. In hot weather, heat transfer to ambient air is reduced and thus more heat needs to be removed by the system. In addition, outdoor cooling-system equipment effciencies and capacities may be negatively affected by higher ambient temperatures and humidity. Condensation that forms on cooling lines also diminishes effciency. Every gallon of condensation reduces cooling capacity by half a ton. Conversely, ventilation around a mold or cooler weather can assist in mold cooling, reducing the burden on the system. •Refrigerant Leaks. A gradual loss of refrigerant pressure due to a slow leak will degrade chiller performance. Not only is it costly to repair the leak and replace the refrigerant, but many cooling gases (especially Freon used in older systems) pose an environmental hazard. be able to use it properly and maintain the operation and maintenance logs mentioned above. Again, reputable equipment suppliers can help you develop an appropriate training program. about the author Tim Miller became heat transfer product manager at conair, cranberry township, Pa., in 2008. Prior to that he worked in various positions with the trane company for 30 years. contact: (724) 584-5500; email: tmiller@conairgroup.com; web: conairgroup.com. GOOD MANUFACTURING PRACTICES The more you know about your heattransfer system and the closer you monitor its operation on an ongoing basis, the less likely it is that you'll deal with problems like those described above. Just as you keep a "recipe" for the injection molding machine setup for every job and every mold you run, you should also establish and maintain a baseline setup guide for your heat-transfer system that includes at least the following information: •TCU model/capacity required; •Chiller model/capacity required; •Ideal áow rate through the mold; •Key pressure drops; •Key temperature drops. Also, since effcient operation of your heat-transfer system depends on the equipment being in good working order, it is important to establish a regular maintenance program and to keep a maintenance log. Most reputable suppliers of heat-transfer systems can help set up such a program and provide service personnel to manage it. Finally, make sure your operators are well-trained in the operation of heat-transfer equipment. The more they understand about why it is important to process effciency and part quality, the better they will ¥ Material Handling Ð Loaders, Tumblers, Material Storage Bins and Dryers ¥ Production Ð Chillers, Water/Oil Circulators and Temperature Controllers ¥ Post-Production Ð Lime Buster, Conveyors, Grinders and Static Eliminators Visit the link below for the full line of IMS Industrial Equipment Supplies: www.imscompany.com/PT5.htm Trusted source for Molding & Extrusion Supplies, Engineered Components & Supplies, EQUIPMENT, MROP Supplies and Engineering Services Visit us on the web or call toll-free 001.888.304.1307 (Mexico) equipment@imscompany.com Since 1949 © 2013, IMS Company. All rights reserved. Plastics technology february 2013 27