Merits of Training

Our powder equipment supplier has told us that we need to use a lower delivery rate to get better application efficiency. Our operators like to run high flow rates to make sure that they get coverage on every part. Is there any training program that they can attend to learn more about how to adjust the guns? Can we set up our equipment so that only the supervisor can adjust the gun settings? Are there any gun controls that can be adjusted for specific powders and parts and accessed with the push of a button?

Allow me to get on my soap box and preach the merits of proper training. I believe that educational programs that are available will greatly impact your overall system efficiency in a very positive way. There are a number of opportunities available to you, including the PCI 2-day Hands on Training program available from the Powder Coating Institute as well as programs that are available from both powder and powder equipment suppliers. There are also industry consultants that will arrange training sessions in your facility designed specifically around your equipment. Most of the training programs that are available will teach you how to properly set your equipment, utilize the available features and actually apply powder to parts to maximize efficiency. I would recommend that you contact the Powder Coating Institute or any one of the industry suppliers or consultants to arrange for training. Your time and money invested will be more than returned in the benefits that your company and people receive.

Racking for Uniform Thickness

We are powder coating fence rails and we have trouble getting uniform film thickness. We changed racks recently and the new rack holds seven parts on each side with a slight stagger to open up the backside of the part. This helped a little but we are still finding a variance of over 1.5 mils from one side to the other. We need suggestions on how to set up our racks and how to adjust our spray guns to get more uniform coverage.

Your question is a good one and is probably similar to problems experienced by many other readers. It is difficult to give you a good answer without knowing some other details but I will attempt to give you some ideas that may help. You mentioned that the new rack design has helped your problem. I am not sure what changes were made to your design from the previous one but I would make several comments. Grounding is an important issue that can impact uniformity. I would make sure that you maintain a proper ground on all of the parts on the rack by keeping the rack contact points clean. Make sure that the design of the rack provides for proper grounding of all parts. If your rack design is such that some part of the rack is robbing powder from the parts this will cause a condition such as you have described. Make sure that your rack itself is not impacting the coating by attracting powder away from the part. Additionally, you do not mention the distance that you have between the parts on the rack. I would recommend that you maintain a distance of about 2 to 3" between parts. This typically gives you a more uniform coating thickness. I also recommend that you make sure that your equipment is all functioning properly. Is the voltage at the spray gun corresponding to the settings at the controls, is the gun-to-part distance the same on both sides of the part, is each gun at least 12" away from the other guns? These are all important details that can impact your coating uniformity. With properly set and operating guns you should expect thickness control that is much closer than 1.5 mils from one side to the other.