Pressure on lumber pricing and processing costs demand that lumber manufacturing be done in the most efficient way, extracting the maximum amount of value from every log that enters the mill. Nature, however, does not make this an easy task, as every log is different in grade, shape, and species.
The proven solution to these challenges in wood optimization is to employ 3D laser and color scanning. Laser and color scanning provide dramatic improvements in yield and value recovery in all areas of lumber manufacturing.
LMI has pioneered scanning solutions in the wood industry for 50 years. This two part blog introduces our chroma+scan and Gocator solutions for sawmills.
Log Optimization (Primary Process)
The first operation in a mill is cutting logs into semi-finished boards (flitches). These operations can occur at up to 30 logs per minute, requiring a large amount of data to be collected and analyzed in a short time. The scanner configuration implemented for 3D log scanning depends on the layout of the log transport system.
When logs travel on a sharp chain into the mill, the common scanner configuration mounts 3, 4, or more laser line scanner heads in a ring layout spaced to provide full coverage. As the log moves through the scan plane, a full 3D map of the log surface is generated. Cutting patterns are then computed and sent to a downstream gang saw that strips away the outer flitches and produces a center cant.
Logs can also be loaded onto a headrig carriage—a kind of moving platform that positions, rotates, and transports the log through a single bandsaw. In this design, multi-line laser scanner heads are mounted along one or two sides of the carriage along the entire log length such that a single capture produces profile data every 6". This snapshot data can immediately be used to make decisions on the next cut for the current opening face. Moving the platform just 6” produces even greater shape detail.
The cutting decisions are an accumulation of multiple scans and back and forth passes through the bandsaw until the final cant is dumped for downstream processing.
After log breakdown, flitches are transported to an edger and can either be processed with a lineal scanning system or with a transverse design.
Stay tuned for part 2 where we will cover board optimization using modular Gocator 200 multi-point 3D scanners.