Operational planning of a plywood plant is a daunting task given the number of variables at play:
- In a typical plywood plant, peeler blocks are peeled to green veneer, which is sorted, dried and sorted again. The dry veneer is further processed and then laid up into plywood panels which are pressed, sorted for grade, and finished.
- The plywood is laid up to various press thicknesses and grades, according to recipes or "builds", which specify the number of plies to be used and which of several possible veneer species, thicknesses and grades may be used for each ply, for each plywood press thickness and grade.
- The finished plywood is sold at a price that depends on the thickness and finished grade. Some of these are usually in more demand than others, and there may be limitations of how much of a particular thickness and grade can be sold at a given price.
- Similarly there may be alternatives for the species and grade, and hence price, of the peelers that are peeled. And they may be peeled to various alternative peel thickness. Sometimes they may be "split-peeled" to different veneer thicknesses from the same block.
- In the absence of raw material supply and sales constraints, various "bottlenecks", typically at the veneer dryers and the presses, will limit the production rate, and these are affected by the logs, the veneer thicknesses chosen, the product mix, and hence the "builds". And the raw material cost and production rate largely determine the production cost and profit. Depending on the log supply and the market it may sometimes be more profitable to use cheaper logs, and allocate the better ones to a sawmill, and sometimes it may be more profitable to use better, more expensive ones. If it is possible to choose which products to sell, there are rich possibilities for optimization there.
- Many plywood plants import, export and trade veneer, which increases the optimization opportunities.
So in a typical mill there are a huge number of possible combinations of alternatives, and it is impossible to calculate an optimum by trial and error with a spreadsheet. Because of the multi-product nature of a plywood plant, and the effect of internal constraints, it is not possible to optimize it successfully using standard accounting procedures. Any attempt to do so will usually result in wrong answers. HALCO's PlywoodOptimization™ solution has been developed to address this issue.
The PlywoodOptimization™ system combines HALCO's WOODSIM™ (bucking simulation) SAWSIM® (peeling simulation) and WOODMAN™ (linear programming optimization) to model your process from delivered logs to finished products, ready for market.
The primary inputs to PlywoodOptimization™ are:
- Log scale data
- Mill bucking practices
- Processing facility operating parameters
- Veneer/plywood/byproduct market information
From these inputs, PlywoodOptimization™ determines an optimal operating plan and reports detailing how the plan should be implemented and the expected resulting:
- Key operating metrics of the processing facility
- Volume and value of finished products produced and sold
Related application descriptions: