Abstract:
Because of their high cost, reducing the number of boards used to fill an
order of dimension parts is an important goal in a lumber rough mill. FLCO
(Fuzzy Logic Cutting Order) is a computer program that achieves this goal.
Using the concepts of fuzzy logic control, FLCO provides a heuristic approach to
this problem. FLCO incorporates a version of the CORY lumber cut-up software,
and provides a model of a rough-mill system that is able to reduce the number of
boards needed to fill a cutting order. FLCO allows different control methods to
be used, including fuzzy logic control, dropping sizes from the cutting order as
their demands are met, and no control. Because of the modularity of its design
the FLCO code can easily incorporate other control methods.
CORY lumber cut-up software provides sawing solutions for boards based
on the values assigned to the sizes in a cutting order. After each board is sawn,
the fuzzy logic controller adjusts the value of each size to achieve the objective
of filling the demand for each size in a cutting order at about the same time.
These new values are subsequently used by CORY when finding a sawing
solution for the next board to be processed. Upon completion, FLCO reports the
number of boards required to fill the cutting order, the average percent area
yield, and the number of each piece recovered.
Three cutting orders, three lumber grades and two types of control
provide a means of determining the effects of fuzzy logic control on reducing the
number of boards used to fill a cutting order. Across all lumber grades and
cutting orders, fuzzy logic control greatly reduces the number of boards as
compared with dropping sizes. Fuzzy logic control slightly reduces the number
of boards as compared with a more complicated method of control across all
lumber grades and most cutting orders, but the difference is not statistically
significant. In addition, the effect of fuzzy logic control on individual sizes is also
examined.
