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If you work with injection molding machines making parts all day long, what would you like to see redone to make them better or easier to use? My list is long. Molding machines are complex and each of us has our preferences. In my evaluations, I have nearly 100 criteria to review and evaluate before purchase. Far too many to discuss, so let's keep it simple and consider just one. At first glance, this issue seems trivial, but it often sends me into a rage. I'm talking about the placement of the wires for the thermocouple and heater bands. These wires supply power and temperature control for the nozzle body and tip. Why does the placement set me off? It is not a complex issue, but in my observation, they are misplaced 98% of the time. Not only do I consider the standard placement dangerous, but it also causes downtime, wastes processors' time, builds frustration, and costs molding shops big money. My bet is that this trivial item costs each molding plant $100,000 a year, perhaps double that. Further, this dollar value does not address the frustration and safety issues that hamper the efficiency of every processor and scheduler in your shop. This is a consistent and significant problem in the industry, and yet it gets little attention. It starts with the machine builder and gets worse Nozzle Heaters & Thermocouples: A Case of Wiring Done Wrong after use in the plant. We are talking about a problem that would save hundreds of thousands of dollars and a few injuries for little to no cost, if done correctly when building the machine. The accom- panying photos show the problem. The photo above shows the wires that supply power and temperature control to the nozzle body and tip. Note that the wires are dangling below the nozzle body and tip. This may seem OK to a non-user. However, there is the force of gravity, and if you couple it with what has to happen in this area of the molding machine, you begin to see the bigger picture. A short list of normal production routines done in this area, and this does not include common nozzle leaks, include: 1. Changing colors; 2. Changing resins; 3. Changing molds; 4. Purging; 5. Opening a plugged or frozen nozzle tip; 6. Changing a nozzle tip; 7. Removing a stuck sprue; 8. Checking the match between nozzle-tip radius and orifice to those of the mold's sprue bushing; 9. Checking melt temperature; 10. Checking nozzle-tip or body temperature; 11. Checking heater bands. Two major points about all the tasks done in this area of the machine: First, processors deal with this area of the press almost anytime the machine goes down. Second, nearly every time we do any of the above routines—or when there is a leak in the nozzle-body assembly or junction of the nozzle tip and sprue bushing—molten plastic Incorrect placement of wires for these components frustrates molders and costs them money to boot. Get more insights on Injection Molding from our expert authors: short.ptonline.com/moldingKH Learn more at PTonline.com KNOW HOW INJECTION MOLDING This shows the wires that supply power and temperature control to the nozzle body and tip. Note the wires are dangling at the bottom of the nozzle body and tip. 34 JANUARY 2018 Plastics Technology PTonline.com K now How By John Bozzelli INJECTION MOLDING