When you walk into a sawmill today, the changes in technology quickly become apparent with the use of programmable logic controls (PLC), optimized log breakdown and automatic lumber scanning and handling. It is easy to observe how the adoption of technology has allowed mills to increase lumber yields and reduce production time and costs.
We believe that technology will continue to change the way sawmills do business. Over the last decade the majority of changes has focused on obtaining greater yields through optimization and new saw technology. While adoption of this technology has been rapid in the softwood industry, the hardwood industry has been a bit slower.
A 2001 study looking at technology adoption by the hardwood industry indicated that only 27% of mills responding to the survey had head rig optimization. A more recent survey conducted by Virginia Tech indicated that approximately 49% of hardwood sawmills now have this technology. Table 1 provides a comparison of hardwood sawmill technology from the 2001 study, published that year in the Forest Products Journal, to the new survey. Mills with optimized edgers increased from 10 % in 1999 to 26% in 2007 and mills with optimized head rigs increased from 27% in 1999 to 49% in 2007.
While costly, the increased adoption of these technologies has improved the industry’s competitiveness and performance. The use of optimization technology typically is associated with mills with larger production, which is still somewhat true. However, even smaller hardwood sawmills have begun to implement optimization for head rigs. Table 2 lists the technology used by hardwood sawmill production.
Technology utilization by sawmills is now moving in new directions. There is a great deal of interest in the use of computer technology to track inventories, maintenance events and inventories, quality control, customer contacts, actual lumber sales and advertising. It is now estimated that 84% of hardwood sawmills utilize the Internet and e-mail.
In the hardwood industry, computers are used for log tallying (60%), lumber tallying (63%) and inventory control (46%). Fifty eight percent of hardwood sawmills have a Web site and 23% are selling lumber on the Internet.
Firms using these technologies have rated the computer-based log, lumber, and inventory technologies as the most important computer-based technology that impacts their performance. Table 3 shows how the hardwood industry uses the Internet.
Changes in the Mill
We discussed new sawmill technology with vendors, suppliers and mill personnel. It became apparent that the advantages optimization can bring to a mill are well understood. The industry has begun to look at technology to solve problems other than the traditional yield increase.
The majority of softwood mills already has adopted head rig, secondary breakdown, edging and trimming optimization and is now looking for upgrades to equipment and greater optimization opportunities. There is also great interest in automated lumber grading systems, which are now a reality and are being implemented in many softwood mills. One example is the COMAC GRADEXPERT, which is capable of determining a grading solution for up to 220 boards per minute. The system can measure bow, crook, twist, skip and wane while detecting knots, pith, stains, decay, bark pockets, paint marks, splits, shake, and worm holes. It already has been installed in several softwood sawmills.
Hardwood sawmills with head rig optimization are now looking closely at edger optimization. Linear fed edgers have gained interest with the industry due to their need for less space and the ability to handle skew in boards. According to Mike Ballard of Sawmill Md., the ability of an optimized edger to handle skew often allows greater grade and volume recovery. Unlike many transfer feeding systems, linear scanned and fed edgers do not require the same squaring and leveling, making installation easier. Linear edgers also often fit into existing space with less modification, which is a big plus in today’s economy.
For both hardwood and softwood mills, there is an increased emphasis on saw kerf thickness, saw guides and saw lubrication systems. As many companies attempt to increase yield through saw kerf reductions, the importance of guide wear increases.
Several companies now market unique coatings designed to increase the hardness and toughness of both saws and guides. An example is EXO technology from UCT coatings, which lowers cutting forces and friction and increases wear resistance.
High pressure water spray has been introduced as a method to cool saws to reduce stress. These systems reduce the use of lubricants, significantly reduce water usage and reduce water damage to bearings. The Danfoss high pressure mist system is one example currently on the market.
As mentioned at the beginning of the article, there is an increased interest in the use of technology to assist in mill performance other than increasing yields. There are several maintenance management systems available to the industry that provide a more effective way to manage maintenance activities, improve manpower utilization and control parts inventory. Such systems can be combined with a Total Productive Maintenance Program (see the April issue of Pallet Enterprise) to greatly improve maintenance efficiency. An example of this type of software developed specifically for the sawmill industry is USNR’s DyaStar.
The ability to link different production systems together to provide better optimization and control over product mix and scheduling also has improved significantly. One example is USNR’s Mill Controller, which can communicate with each connected optimizer and automatically adjust production priorities to meet the mill’s production and market needs.
On the Horizon
It has been stated that the only constant is change. The future will bring great changes to the sawmill industry through the introduction of new technology. A few new technologies look particularly promising.
The first is scanning and optimization for hardwood lumber grade recovery. While lumber volume optimization based on log shape is currently available, researchers are working to be able to identify defects within the log using real-time scanning technology. Several researchers have attempted to use – with limited success — technology similar to CAT scanning technology in the medical profession.
However, a new approach being tried by the Hardwood Scanning Center at Purdue University, headed by Dr. Razo Gado, is working on a system that would scan hardwood logs to a depth of 27 inches at a scan rate of 1 log per minute. The group has developed software for such a system for both the sawmill and veneer industry.
Another approach to lumber grade optimization in hardwoods is being taken by Ed Thomas, a research scientist with the U.S. Forest Service Northern Research Station. Ed is working to develop a system that uses high resolution laser scan data to examine the potential for using laser scanning for detecting internal defects. The concept behind it is that external defect indicators provide information about internal defects. Defects can be classified based on type and an estimated internal shape.
The second area where researchers have been focusing is the development of better methods to estimate production costs for sawmills. Typically, the cost of lumber production is allocated equally to all the lumber produced from a log. In reality, there are different costs associated with what part of the log the lumber is produced from and what equipment is used in its production. Several new methods of estimating or calculating raw material and production costs are being developed. The Appalachian Hardwood Center in Morgantown, West Virginia is working on a methodology that would allow for better lumber tracking during production to assist with real time and more accurate information on costs and yields.
Conclusion
There have been a great number of changes in the industry in regards to technology and optimization. While the majority of efforts in the past focused on improving yield, there has been a steady increase in the use of technology to collect and process information that directly impacts mill performance. While more technology will become available to help increase yields, we will also see more technology to assist with maintenance, quality, sales, and marketing.
(Editor’s Note: Brian Bond is a Virginia Tech associate professor and extension specialist in the department of wood science and forest products; he writes a regular column for Pallet Enterprise called Sawmilling & Treating Insights. Brian Perkins is a Virginia Tech graduate student in the department of wood science and forest products.)
