Issue link: https://www.e-digitaleditions.com/i/941907
POWDER COATING, February 2018 23 up rapidly close to the oven's operating temperature, and according to the cure window, we want to be in that temper- ature range for no more than 10 min- utes maximum. Fortunately, there are instruments available that provide us with the capability and confidence to properly and repeatedly cure the coat- ings that we apply. Thermal profile data logger. There are a few manufacturers of these devices, and they offer them in a varying degree of technical sophistication. With the use of temperature probes and the data logger (a small computer that records the temperature and time), the custom coater is able to attach the temperature probes to areas of varying thickness and run the bedframe through a dry run. The resulting data will provide the cus- tom coater with an accurate recipe for baking the bedframe. With the device that I am familiar with, when combined with the powder manufacturers' cure window data, a value will be produced that gives clear indication if cure has been achieved or not. This device can and should also be used to profile your oven on a regular basis to ensure proper temperature balance. For those powder coaters who run a conveyor line coating system, thermal profile data loggers are also available in a wireless configuration that allows for real-time data reporting. Pyrometer (infrared thermometer). This is an invaluable tool that provides the custom coater with real-time data on the floor. The downside is that you have to open the oven and hold the pyrometer 8 inches to 12 inches from the piece to get an accurate readout. Our powder coaters are trained to hit each piece with the pyrometer before pulling it from the oven every time. Caution must be taken, however, to consider the amount of time the piece has been in the oven. Meaning, just because you get a readout of 360°F on the piece and it has been in for 20 min- utes does not mean it is cured, but the process certainly has begun. In our own tests, we have seen a 10- to 15-degree drop in part temperature right now, for the sake of argument, if our oven is set at 425°F, the product is going to take 20 minutes to get up to 356°F. Looking at our cure window, to achieve full cure of our coating, the bedframe needs to be in the oven for an additional 15 minutes at a minimum. The challenge comes when we have to allow for the 1/16-inch sheet metal dec- orative headboard and the solid cast iron bedposts. The varying mass and density complicates the cure process because these two additional compo- nents are going to heat up at varied rates, increasing the risk of over- and under-bake. Important instrumentation W i t h o u t t h e l u x u r y o f b e i n g i n v o l v e d i n t h e design process, custom coaters must be able to adjust their baking process to accom- modate products like our hypothetical bedframe. At 425°F for 35 minutes, you can be sure that the 1/16-inch sheet metal on the bedframe will have heated X X D J S C B N P U T V D D X G for Ind our Leader o G X Y X G X ! P O J _J N P D D F U B D G ustrial Finish G r In Masking S U B D J S C B N P U T V D ! G hing. G Solutions U B D J N P D F U N P D F U aint Masking (tapes & di P Custom Molded iscs) Custom Die Cut 3D Printing astest turnaround F • Y SHIPPIN Y SAME DA • ts y d time in the Masking Industr STOCK ORDERS on all NG Plugs and Caps 414.421.2700 . 414.421.2600 F: P. 414.421.2600 F: P WI 53132 anklin, Fr ood Park Drive est Oakw W 5500 WISCONSIN P: 562.944.1410 562.944.1400 F: P: CA 90605 , Whittier Suite Q , venue A 9925 Painter ALIFORNIA C endor Managed Inventor VMI (V • SOLUTIONS Expert Design Eng • RAPID PROTOTYPING available with our 3D Printer • location TIPLE T • referred Conv 3M P • astest turnaround F MUL • 440.463.3777 F: P: 414.421.2700 404.414.0448 F: : GA 30115 Canton, y Place c amer 301 Gr GEORGIA y) Programs available ged Inventor ineers to create CUSTOM NG available with our 3D Printer ns Nationwide verter y d time in the Masking Industr 281.219.3300 F: P: 414.421.2700 0.463.3777 F: H OH 44095 Cleveland, antage Parkw V 15401 e Drive oodmer W 264 OHIO 281.219.3344 9.3300 F: TX 77032 ouston, Suite 104 est, W ay age Parkw TEXAS 800.556.7188 877.487.1950 800.556.7188 800.556.7188 855.219.3300