https://www.pfonline.com/atom/zones/controls-parts-racking Process control and monitoring devices can enhance the operating efficiency of your powder coating system. When you look at first-pass transfer efficiency, consider a system where the guns are triggered on at all times and the space between the parts is equal to the part size. The highest achievable first-pass transfer efficiency of your system will be no more than 50 percent because one-half of the powder is sprayed into the air. Using a stop watch, record the amount of time the guns are spraying without parts in front of the gun. System history has shown us that the time will vary from 20 to 60 percent of the time the guns are spraying with known parts in front of the guns. Your overall first-pass transfer efficiency could improve from 20 to 60 percent based on gun triggering. An added benefit of automated gun triggering is the ability to adjust the spray duration to either reduce heavy edges on parts or to increase wrap on parts (see below).