CURE MONITORING OF PLYWOOD AND COMPOSITE WOOD PRODUCTS

NO DIAGNOSTIC TOOLS EXIST TO DIRECTLY MONITOR THE QUAILITY OF MANUFACTURING PARAMETERS OF PLYWOOD AND OTHER WOOD-BASED COMPOSITES DURING THE PRESSING WHERE ADJUSTMENTS OF TIME, PRESSURE OR TEMPERATURE CAN BE MADE. LACKING SUCH TOOLS, MOST MANUFACTURING GUIDELINES HAVE BEEN DERIVED AFTER-THE-FACT USING TRIAL AND ERROR DESTRUCTIVE AND NONDESTRUCTIVE TESTING METHODS. AS A RESULT, THE PROPERTIES AND FAILURE POTENTIAL OF THESE PRODUCTS VARY WIDELY. THE OBJECTIVES OF THIS FEASIBILITY STUDY ARE TO DEMONSTRATE (A) THAT USEFUL SENSORS CAN BE DESIGNED, FABRICATED AND CONFORMABLY MOUNTED ON A PRESS PLATEN WHERE EXTREME ENVIRONMENTAL (PRESSURE AND TEMPERATURE) CONDITIONS EXIST, AND (B) THAT THE SENSOR'S ELECTRICAL RESPONSE CAN PROVIDE USEFUL DIAGNOSTIC INFORMATION ABOUT THE DYNAMIC PHYSICAL CHANGES AND CHEMICAL REACTIONS THAT ARE OCCURING IN THE WOOD/RESIN/MOISTURE COMPOSITE. THE PROPOSED TECHNIQUES ARE BASED ON THE PRINCIPLES OF MICROWAVE DYNAMIC DIELECTRIC ANALYSIS. USING A RESONANT MICROWAVE (ABOUT 700-800 MHZ) SENSOR, THE REAL AND IMAGINARY COMPONENTS OF THE BULK COMPLEX DIELECTRIC CONSTANT ARE DIAGNOSTIC INDICATORS OF THE CURE REACTION CATALYZED BY HEAT AND MOISTURE. THE PROJECT WILL FOCUS ON SIMPLE PLYWOOD FIRST, FOLLOWED BY THE MORE COMPLEX MEDIUM DENSITY FIBERBOARD.