Study of the production in a custom-cut sawmill through the use of discrete event simulation and experimental design

Introduction: When sawing logs without diameter sorting, the cutting program generates decisions and routes depending on the log’s appearance and machine load. Objective: To optimize the production flow of a custom-cut Pinus radiata D. Don sawmill, through detection and analysis of critical machines, using discrete event simulation and experimental design. Materials and methods: Two simulation models were developed for sawing logs with lengths of 2.5 and 5.0 m, and diameters between 34 and 44 cm to produce sawnwood with a thickness of 5/4" with variable width. The number of logs processed per shift was the response variable of the model. Heavily-used machines and transports with long queues were candidates for critical machines. The impact on production was determined by means of experimental design, where the factors assessed were: (A) delivery from bandsaw carriage 1 to band saw 3, (B) increased debarker capacity, (C) failures eliminated from bandsaw 1 and 2, and (D) direct delivery from bandsaw 2 to edger 2. Results and discussion: Modifications to the production flow were proposed because factors B, C and D significantly increased (P = 0.1) the production level (logs per shift); the increases over the sawmill’s initial condition were 13 and 18 % for lengths of 2.5 and 5.0 m, respectively.  Conclusion: Simulation and experimental design can be applied in small and medium-sized sawmills to improve production when processing logs without diameter sorting.