On my first visit to Pleasant River Lumber, I sat down with owners Chris and Jason Brochu to discuss their needs of an automated stem breakdown system for their yard with mobile log slashers. It required at least 3 or 4 units to keep up with mill production. Over-trim was an issue and block optimization going into the mill was nonexistent. The subcontract cost and the lack of yield into the mill seemed that a quick payback could be achieved with an automated system.
Initially, Chris and Jason had envisioned a single line, linear, twin saw cut up arrangement. There were several issues with the design, overall production being a primary concern. The linear system could only produce a maximum of 4 to 5 stems per minute into merchandised blocks. They need 9 stems per minute…. I showed them video tapes of recent multi-saw transverse systems we had installed easily doing 9 stems per minute and they quickly realized it was what they needed.
Layouts were presented and PRL contracted with Endurance to supply the equipment necessary to modernize their woodyard.
Stems are presented to the system by twin decks with a waterfall. The waterfall helps to straighten and separate tangles. Stem lengths range from 30′ to 60′ and diameters run typically from 6″ to 20″. Species are all softwood. An Endurance 2 Stage Singulator positions the stems for scanning. Progress Engineering installed a new type of transverse scan camera that detects overall stem length and the diameter. With this information, a look up table based on known cut dimensions for given stem types is utilized to determine the proper cut solutions. Block lengths of 8′ through 16′ are considered.
After scanning, stems are even ended by the Endurance Stem Positioner and indexed for cutting. The Endurance Stem Positioner allows for the incoming stems to be positioned while the previous stem is being cut into blocks. The operator is located in a position 10′ above the log flow where he has line of sight to the infeed decks and the entire merchandising process. He can override the automatic system if he needs to cut a lily pad or if he determines that the sawing solution needs altering.
Three (3) 72″ diameter saws slide on carriages to achieve all necessary cuts in a particular stem. Hydraulic Linear Positioners move the carriages and the up/down motion of the saw assemblies. The Positioner is an open architecture design and allows defect blocks to drop directly into the waste system after being cut.
After getting the input to transfer, the Positioner rotates to place the optimized blocks on the Outfeed Conveyor. A continuous flow of log blocks heads out to the receiving pockets. The decision was made early on to not tie the new Merchandiser directly to the mill.
Blocks are sorted by diameter and kicked into the four receiving pockets by high speed Endurance Pinball Kickers. Blocks are stored in the yard and supplied as needed to the sawmill.
The Brochu’s are very pleased that the new system can cut enough blocks in one shift to run the mill’s two shift operation.