By Jennifer McCary
Mansfield, Ark.
Gilbert Travis is no stranger to the challenges of starting up new sawmill equipment systems. He has been involved in the design, equipment selection and installation of more than a dozen sawmill upgrades during his 30+ years in the industry. He's well aware of the variety and scope of the little hiccups that can bring a multi million-dollar expansion and startup to a screeching halt. So you tend to notice when a man of that background enthusiastically reports "Of the equipment I have ever bought—and I have bought million of dollars worth—this last upgrade has absolutely had the best payback of any I've ever done!"
Travis Lumber Co's 1999 upgrade—the fifth of a multi-phase 10 year expansion program—is also Advanced Sawmill Machinery's (ASM) first curve-sawing installation (see page 14). The sawmill's objectives were threefold: to achieve 100MMBF annual production while reducing operating hours from two shifts to one; to increase lumber yield and to make the conversion without any downtime. That third goal is particularly crucial for an independent operator whose capital reserves simply can't absorb downtime interruptions as easily as a publicly held corporation.
Left to right, John Chapman Jr., sawmill foreman; owner Gilbert Travis; and Jerry Craig, superintendent
The owner and his experienced management team did a lot of in depth study and analysis before making their equipment selections. "We wanted a piece of equipment that we felt was as close to bulletproof as it could possibly be," Travis emphasizes.
The May 1999 startup was achieved with zero mechanical, hydraulic or saw problems and the mill was back up to production levels in just ten days. The only reason it took ten days, Travis notes, is because it took a little more effort to fine tune the PLC controller that manages system flow. Production is now up to 40MBF per hour on a single shift, eleven hour, five-day operation, or 108MMBF annually. Today, the mill produces in one hour what it produced in a full day 12 years ago.
Yield gains are five times more than the level the owner had calculated it would take for the expansion to be profitable. A total of 26% increase in yield has been achieved since a startup a year ago. Those gains are the result of converting to thin-kerf saws as well as curve sawing.
Initially, Travis Lumber programmed and ran the new ASM system as a straight sawing system to give employees a chance to get used to thin kerfs before adding the curve saw technology. After four months, which is actually two months earlier than scheduled, the system's programs were converted to curve-sawing. Thus the lumberman has been able to document a solid 8% yield improvement resulting solely from converting to curve-sawing, with all other factors being equal.
ASM Vice President Russell Robertson, project engineer on the upgrade, provided extensive training for Mill Personnel. He was on site two weeks before and two weeks after startup to ensure a smooth transition.
The 3.5 million dollar project includes the Inovec optimized, ASM curve canter and versa gang curve-sawing system, as well as upstream and downstream system modification to accommodate the increased volumes and speeds. A half-million dollars of that sum was invested in a filing room upgrade to prepare for maintaining the new thin-kerf saws.
The heart of the upgrade is a simple but highly effective ASM curve-sawing system that includes an independent curve canter and a 10 in. single arbor versa gang curve saw with a 27 ft. transfer deck between. A sequence hook deck delivers two-sided cants from both primary breakdowns (sharp chain/twin band and carriage head rig) through the curve-saw system's Inovec transverse curve master scanner. The optimizer reads and calculates the best curve solution. Cants are positioned on an ASM round log sharp chain transport system similar to an ASM round log sharp chain system but with smaller spikes. As the cant advances, Forano conical canter heads are slewed and skewed to chip the profile solution. The canter is capable of sawing an S curve and is handling up to 4in of sweep in 16 ft.
the story continues...
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