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Paint EfficiEncy audit material off the substrate, both resulting in reduced transfer efficiency. Using the paint gun manufacturer's suggested air cap and fluid tip combination for the viscosity of the product being sprayed will provide the best results in finish quality and efficiency. Size and shape of the part. To improve transfer efficiency, it is important that the spray pattern height matches the part being sprayed. Material blow-by from too large of a spray pattern reduces transfer efficiency. The tip size should be sized to the largest spray pattern height for the parts, but not bigger. It is also important to purchase a spray gun with a fan pattern adjustment knob so that, as the part size varies, the operator can adjust the spray pattern height down to match the part size. Operator technique. Optimal operator training can have a big impact on transfer efficiency. Operator spray techniques such as spraying the right distance from the part, spraying parallel to the part, and triggering and detriggering at the proper time can affect transfer efficiency by 10 to 30 percent. For example, it is important to overlap each successive stroke (e.g., 50 percent for conventional spraying or 25 percent for airless spraying) using a crosshatch overlap when required. Triggering the spray gun at the beginning and detriggering at the end of each stroke is recommended. This minimizes the lead, and even a small decrease in leading and trailing edges can reduce overspray and result in significant improvements in transfer efficiency. Spray Gun Set up Comparison Applicator selection. Selecting the most efficient spray gun for the intended application is important in optimizing the efficiency of any spray operation. Conventional air spray, compliant, HVLP, air-assist and electrostatic all offer excellent benefits, depending on the application. Mix Room Equipment In the mix room of finishing operations, pumps are often the biggest consumers of energy as a result of compressed air consumption. Improving the efficiency of current equipment, or switching to hydraulic or electric pumps that use less energy are effective ways to reduce long-term energy consumption. Pneumatic systems are often the choice of most finishing operations because they are easy to install and operate. And because air is often an existing power source in the plant, the upfront cost is typically less expensive. Hydraulic systems are more cost-efficient than pneumatic systems because they use about 1/3 of the energy of pneumatic systems. A system using hydraulics can match the power of a pneumatic system even if the horsepower of the hydraulic system is listed as less than that of the pneumatic system. With the highest up-front expense, electric motors often provide the largest energy savings in a finishing operation. Most notably, they offer direct conversion of electrical energy to mechanical pumping. This not only uses less energy, but it also eliminates the inefficiency of compressed air systems. A table on the next page illustrates how switching from pneumatic to electrical pumps can yield thousands of dollars in savings for finishing operations. Air compressors have ongoing liabilities, including leaks, maintenance and equipment downtime that can also lead to inefficiencies. In fact, the majority of air compressor costs are not from the initial capital investment but from energy usage in their 10-year lifespan. Another benefit of electrical pumping is the improved control and automation potential. Pumps Technology Comparison PRODUCTS FINISHING — pfonline.com 25