Application Equipment Maintenance
Posted on Tuesday, January 24, 2023
By Josh Gilmore
Similar to regular maintenance on a vehicle to sustain maximum fuel efficiency, your powder line must be maintained periodically to achieve maximal first pass transfer efficiency. In both cases, there are two primary areas that need routine attention: consumables and preventive maintenance. Consumables, or wear-items, are bits and parts of the system that need to be restocked or replaced to keep the car going or the powder line producing. Preventive maintenance (PM) is mainly inspecting areas, deep cleanings, and trying to stay ahead of any potential issue that might come up.
There are different forms of consumables, some that are value-adding such as windshield washer fluid, and some that are necessary for the vehicle to operate like gasoline. The washer fluid does not get you down the road, however it creates a better experience for the driver if the windshield gets dirty. The main value-added consumable you will see within a powder coating operation is the powder itself. Non-value-added consumables, which tend to require more effort to maintain to ensure sure they are not worn out, are compressed air, air hoses, powder hoses, powder tubes (throat), gun nozzles, and hooks to hang the parts.
Similar to replacing consumables in your own car, it is nearly impossible to have a consistent, regular schedule to replace these items. Timing will rely heavily on how often the equipment is used. Grandma’s car only needs tires every ten years because she only drives to church and the grocery store, whereas I am on the road 30+ weeks a year and am replacing tires every two to three years. Similarly, a hobby job shop doing powder coating in a garage will go through consumables less frequently than an automated powder line coating eight hours per day.
Replacement of value-added consumables is much easier to estimate. It is very easy to look into a box or a hopper, see that the powder supply is running low, and replace the box or refill the hopper. However, some non-value-added consumables are more difficult and require some intervention to take apart and inspect the equipment. Powder is actually an abrasive substance and depending on additives, like metal flakes and other textured ingredients, can become even more aggressive. Over time, the powder wears down components of a powder coating line, decreasing efficiency and overall effectiveness of the application equipment. The spray nozzle or deflector being used will suffer from wear due to the abrasiveness of powder, as will the throat in the powder pump and the powder outlet tube of the gun. These parts are all known wear items and have been designed in all powder coating equipment to be replaced as wear occurs. This prevents the end user from having to purchase an entirely new gun or pump. Some of the preventive maintenance steps we will look at in the next section will help determine how frequently these parts should be replaced, and most importantly how often they should be cleaned and inspected.
Consumables Replacement Schedule
Open to outside factors like the coating environment, temperature, humidity, and general human interaction, other consumables that need replacement on occasion include your hoses, which can be run over by forklifts, accidentally spliced open, or begin to leak as a result of age. Hooks are a VERY important consumable that need to be checked regularly. If you have a hook coated with multiple layers of cured powder, your part will not be grounded, which means it will be difficult to coat. Be sure to strip hooks regularly and replace them on occasion. Electricity and compressed air are relatively plentiful in the coatings world, as long as the bills are paid, and the air supply is consistently clean and dry.
Unlike the consumables that usually only get replaced once they are completely worn, preventive maintenance (PM) is a measure that takes place before an issue arises and a proactive way to minimize downtime in a powder coating line. We all know that downtime is expensive and following a PM schedule can help keep it to a minimum! All equipment manufacturers have their own PM schedules, and they all have a few steps in common—most importantly cleaning and inspecting. Knowing the equipment, and regularly cleaning and inspecting it, allows for early detection of issues before a potential loss of production.
PM Replacement Schedule
One might ask, how frequently should PM measures take place? Again, I tell you, there is no specific answer to this question. Your car’s oil might be changed every 3,000 or 5,000 miles depending on if you’re using a synthetic oil or not. Similarly for powder coating equipment, it depends on how often the equipment is used, for how long, and the environmental conditions of the operation. Some things should happen every single shift, like cleaning the guns, hoses, and powder pumps, inspecting all for wear, and making sure a good, solid ground is provided at the part.
It is also recommended to, on a daily basis, inspect the gun electrode, check all of the gun output settings, verify that the gun-to-part distance has been maintained, clean all booth walls and ceiling, and check for proper fluidization of powder. Doing this will help determine the wear of consumable items and aid in establishing a routine schedule for replacement. It will also enable you to keep an eye out for impact fusion in various components of the system. Impact fusion happens when there is moisture in the powder or when particles align perfectly and join to become larger clumps. These conglomerations can block a hose or powder passageway creating more surface area for additional powder to stick to and constrict powder flow.
Less frequent maintenance tasks include checking the hoses for impact fusion, cleaning all of the gun connections and cables, as well as the outside of the booth. All of these tasks should be performed weekly. Monthly cleaning and inspection of hoppers, pickup tubes, and fluidized plates can help determine if you have oil in your compressed air that is being collected on the fluidized plate. This also ensures that the powder is fluidizing properly. For a full maintenance checklist and schedule, refer to Powder Coating: The Complete Finisher’s Handbook published by the Powder Coating Institute, Appendix D: Maintenance Checklist.
Whether you’re changing the oil in your car or replacing a powder outlet tube once a year, keeping up on the preventive maintenance of your equipment will prolong its life. Completing these tasks regularly will establish a steady record base, help determine how frequently wear-parts are being consumed, and enable you to include them in the PM schedule. For instance, if during the regular inspection of the powder pump, it is noted that every three and a half months or so significant wear is showing in the powder throat tube, an action to replace the throat tube every three months should be added to the schedule. This will prevent total failure of the component and keep product consistently flowing out the door. With a solid PM program, together, like a couple of plucky 2007 Toyota Tundra pickups, we can reach the 1,000,000-mile mark… Errrr, 1,000,000 pounds of powder mark!
Josh Gilmore is Central States regional manager at Sames.