RAM (Rough Mill Analysis Model)
Research Brief #6
Louisiana Forest Products Laboratory
Louisiana State University
Baton Rouge, LA
Research Objective
Develop user-friendly simulation software for both crosscut-first and rip-first rough mill production systems.
Synopsis of Results
Rough mill simulation software enables to design new or model existing
crosscut-first and rip-first operations and observe influence of input material, cutting order, plant
layout, processing and transportation times on parameters such as yield, throughput, processing
time and machine utilization.
Program Description
- The simulation model runs on IBM PC-compatible computers.
- The simulation model can be easily modified to accommodate various rough mill layouts. It is
equipped with a user-friendly interface to eliminate the need for user programming and simulation skills.
- The model contains a realistic board entity generator comprised of a database of digitized boards
and a program simulating cutup of these boards for both crosscut-first and rip-first rough mill systems.
- Cutting order describes length, width and number of parts information.
- Part quality can be clear two face (C2F), clear one face (C1F), or sound two face (S2F). Cutting
order information requires descriptions of part lengths, widths and quantities.
- The user can enter a feed rate for the unstacker; select the number of parallel machines for each
operation; enter transportation times, machine processing times, and surge deck capacity for each
machine; and enter sorting operation times.
- To provide lumber entities for the RAM simulation, lumber from the database is randomly
sampled to produce the userspecified grade mix. This grade mix may be comprised of a single
grade or any mix of the six grades. It is possible to use randomly sampled lumber from a
previous run or to use a new random sample of lumber. This insures that any difference between
simulation runs is caused by changes in input parameters and/or dynamic changes in the system
rather than by variation in the board entities.
Conclusions
A user-friendly rough mill simulation software package called RAM was developed. Individuals
with no knowledge of simulation can use this RAM software to model current or proposed rough
mills. A database of digital lumber descriptions allows the generation of realistic entities to flow
through the modeled rough mills. Ram was validated in both the crosscut-first and the rip-first
rough mills. Validation results show that RAM closely describes yield, processing time, and
machine utilization of modeled rough mills.
Researchers
Rado Gazo, Post-Doctoral Researcher
Louisiana Forest Products Laboratory
LSU Agricultural Center
Philip H. Steele, Professor
Mississippi Forest Products Laboratory
Target Group
Secondary wood manufacturers
Methodology
Rough mill yield, throughput, processing time and machine utilization can be determined by
simulating the material flow in the rough mill. The RAM (Rough Mill Analysis Model) is a
processoriented simulation software. The user describes the rough mill operation, and RAM then
simulates the flow of the specified lumber grade mix through the model rough mill in real time.
Boards for the simulation are randomly sampled from a digitized database of lumber. A
computer program simulates a three-stage rough mill lumber cutup by both the crosscut-first and
rip-first systems. For the crosscut-first system, these stages are crosscutting, straight-line ripping,
and salvage crosscutting. For the rip-first system, the three stages are an all movable blade gang
ripping, crosscutting, and salvage straight-line ripping.
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This page was last updated: 29-MAR-95, by: James Babin <jbabin1@tiger.lsu.edu>