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comes out and gravity works to allow the plastic to cover the wires. The results are evident in the photos above. When this happens, there is no easy way to clean the molten plastic off the wires. The electrical wires have 120 V or 220 V on them, so most processors just leave them alone and hope they don't break or short out during their shift. If you are thinking about turning off the power and cleaning things up, that would shut the job down, and that is a no-no. The norm is to let it ride, and with time, more plastic builds up until a wire breaks or shorts. Then the job is shut down and maintenance is called to replace all the wires, heater bands, and thermocouples. They cannot be salvaged. Things are often not labeled well, so there are times when the wrong voltage heater band and/or type of ther- mocouple is installed. Then "Murphy" shows up and more time is wasted as troubleshooting takes on some serious downtime. When finally fixed, the processor turns on the heaters, waits for everything to come back up to temperature, and then spends significant time starting up the process, sampling parts etc., etc., etc. What does it take for the industry to understand that plastic is subject to gravity? Somebody explain to me why these wires are not in a protective cable (one that can be easily removed for replacement) and are routed not down, but to the non-operator side of the machine to avoid the plastic getting on them in the first place. In addition, everything should have plugs or quick discon- nects, as these components are replaced often. To add injury to insult, there is accompanying frustration. More than half the time this area has guards, brackets, or some physical barrier that severely restricts access—to the point that the processor or maintenance person needs to be a gymnast to get the work done. This difficulty can and does cause accidents. It's not unusual to get burned, even with the best of protection. Yes, it is critical to shield this area to prevent molten plastic at 20,000 psi (1500 bar) or higher from harming those in the vicinity. Safety first, no question, but some machine builders do provide an easy-to-use mechanism whereby the shield slides, lifts, or folds so that it is easy to move it out of the way for work to be done safely. This "room to work" issue is so frustrating. I often wonder if the people who design the machine ever have worked on it. With a little thought, maybe a little extra time in putting it together, there would be less machine downtime and lower maintenance costs, along with fewer injuries and stressed-out processors. ABOUT THE AUTHOR: John Bozzelli is the founder of Injection Molding Solutions (Scientific Molding) in Midland, Mich., a provider of training and consulting services to injection molders, including LIMS, and other special- ties. Contact john@scientificmolding.com; scientificmolding.com. During normal production, gravity will pull hot plastic down, where it will build until it completely covers the wires, making them impossible to clean. (Photo-right: Bill Hartwick, Filter Specialties Co. & Enersavecontrols Inc.) The standard placement of the wires for the ther- mocouple and heater bands is dangerous, causes downtime, wastes processors time, builds frustration, and costs molders big money. Solidified Plastic 36 JANUARY 2018 Plastics Technology PTonline.com I N J E C T I O N M O L D I N G K now How