MODELING LUMBER MANUFACTURING PROCESSES USING MONTE-CARLO COMPUTER-SIMULATION

Current methods for calculating lumber target size have been developed on the assumption that shrinkage, planer allowance, and finished lumber size are all constants. These methods do not allow for any interaction between the variable processes including green lumber variation, shrinkage, planer allowance, and finished size. if further gain in lumber recovery is to be realized. a method must be developed to account for interrelated stochastic processes found in lumber manufacturing. A computer simulation model was developed to account for, and represent, the interaction of the varying parameters used. The simulation model uses Monte Carlo techniques to simulate the manufacturing of a board. Each process is simulated by sampling a value at random from a probability distribution representing the process being tested. The model uses the value obtained by the random sample to calculate the dimension of a board output by the process. For this set of data, at least, the computer simulation model using Monte Carlo technique predicted the percent of skip dress lumber very accurately while the traditional method greatly under-predicted it. By simulating actual lumber manufacturing processes, more accurate studies can be developed to find opportunities for increasing the lumber recovery and profitability of a lumber manufacturing facility.