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The 23rd Annual WMI Workshop on
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| 7:30 - 8:20 | Registration |
| 8:20 - 8:25 | Introduction and Welcome Ryszard Szymani, Director, Wood Machining Institute (WMI), Berkeley, CA, USA |
| 8:25-8:45 | Economics of Sawing Variation and Potential Gains in Lumber
Value Recovery Using Thin Kerf Accurate Sawing and Sawing Options to Improve Profits Ryszard Szymani Optimizing log breakdown and the value of kerf and target size reduction will be discussed and examples of thin kerf accurate sawing will be presented. In addition, the WOODCIM an integrated optimizing software for sawmilling industry developed by VTT, Finland will be introduced. Using this program for integrated planning and optimizing system for sawing the logs into lumber grades according to the end user specific needs, it is possible to increase the profit or sales value of the production by several percent. |
| 8:45-9:15 | Wood Characteristics and Properties which are of Concern when Sawing and
Rupture Patterns in Cutting Wood – DVD Ryszard Szymani Review of the basic anatomical, physical and mechanical characteristics and properties of wood as they relate to sawing process will be presented including specific gravity and moisture content and temperature of wood and cutting forces during rip-sawing and cross cutting. Effect of spiral and interlocked grain, knots, and growth and wood drying stresses on saw stability (eg. saw blade binding and cases of workpiece kickback) and sawing feed rate will be discussed. |
| 9:15-10:00 | Circular Saw Stability Criteria and Advances in Saw Tensioning and
Tension Evaluation – DVD Ryszard Szymani This presentation provides a summary of advances in research and developments on thin circular saw vibration and stability and saw tensioning. The first part will include video demonstrating condition of critical speed. The second part covers stresses due to tensioning, rotation and thermal effects that influence saw stability, and reviews the developments in saw tensioning methods and latest equipment used for saw stiffness evaluation. |
| 10:00-10:30 | Coffee break |
| 10:30-11:15 | New Design Developments for Circular Saw Arbors Allen Gallant, Forest Products Technical Sales Representative, Vancouver Gear Works, Ltd., Richmond, BC, Canada This presentation will discuss new circular saw arbor design developments. It will introduce manufacturing improvements completed in the past 2 years by VanGear. The importance of saw eye to saw arbor fit will be discussed and old to new design will be compared. |
| 11:15-12:00 | Saw Tooth and Gullet Design, Advances in Saw Tipping Materials and Saw Tip
Failure Analysis Ryszard Szymani Variable saw tooth and gullet design and latest developments in saw tipping materials, including new Stellite, tungsten carbide, cermet, ceramic and PCD will be discussed. Failure of saw tips will be also covered. |
| 12:00-1:30 | Lunch break |
| 1:30-2:15 | Understanding Sawing Accuracy and Process Reliability In Double Arbor Gang Edgers Warren M. Bird, President, California Saw and Knife Works, Inc., San Francisco, CA A simple model explains why statistical analysis is generally misapplied to the measurements of lumber produced by guided circular saws, whether in single arbor or double arbor machines. A close look examination of measurements of double arbor mismatch or single arbor edging – in which saw flexibility plays a dominant roll – shows that the assumption of a normal distribution of board thickness is inadequate, and that the use of standard deviation to infer shifts in product quality is inappropriate. A new straightforward method for lumber size analysis will be presented. |
| 2:15-3:00 | Computerized Bandmill Monitoring for Increased Productivity Donald Miller, Engineering Manager, Lacey Harmer Company, Portland, Oregon The current technology tools in the computer and electronics industry today are now available to the wood industry for accurate bandmill monitoring. By the addition of an accurate and fast-responding proximity sensor and an industrial computer we can significantly increase throughput, decrease board size variations, reduce downtime, reduce saw damage, and supply real-time reports. This arrangement is best suited for high-speed applications, such as Twin and Quad bandmill small log breakdown and Resaw machine centers. |
| 3:00-3:30 | Coffee break |
| 3:30-4:15 | Machinery Maintenance Problems Relevant to Sawing on Primary and Secondary Sawmill Equipment Joe Shields, Senior Mechanical Service Technician, USNR, Woodland Division Typical criteria for machine performance will be discussed including: What affects sawing accuracy and dependability (including minimal amount of unscheduled saw changes); Positioning accuracy; Feeding accuracy (Feed roll diameter error); How does scanning accuracy affect sawing performance; and Rules for all Chipper Gangs and Chipper Quad Bamdmills. |
| 4:15-4:45 | An Update on Gullet Cracks in Saws and How to Avoid Them Ryszard Szymani Gullet cracks in saws have been a subject of many publications particularly by saw steel and saw blade manufacturers. There have been improvements in saw steel manufacture as well as in equipment for saw tipping with Stellite and tungsten carbide tips and saw leveling and tensioning equipment. This paper updates information on the status of gullet cracks in circular and band saws and how it is possible to avoid them. |
| 4:45-5:00 | Questions and Answers Ryszard Szymani |
Tuesday, March 11, 2008
| 8:15-9:10 | Ways to Improve Bandsawing: Bandsaws Dr. John Taylor, Sawmilling Group, Lumber Manufacturing, FP Innovations, Forintek Division, Vancouver, B.C., Canada The bandsaw is still one of the best saws for high-speed, thin-kerf, mismatch free, cutting. This is evident in most new double length infeed log breakdown canter lines, where the saws of choice are twin 5-ft or 6-ft bandmills. This presentation includes information collected over many years and questions and discussions are encouraged. The presentation will be drawn from the following topics: Levelling; Tensioning; Bandsaw Cutting Behaviour; Washboarding (I & II); Variable Pitch; Cutting Frozen Wood; Bandsaw Monitoring Systems. |
| 9:10-10:00 | Improving the Sawing Process by Management of Stresses
in the Tool and in the Wood: Three Case Histories Warren M. Bird, President, California Saw & Knife Works, Inc., San Francisco, CA An effective response to a difficult wood machining problem may require the integration of mechanical engineering, materials science, and statistics with the intuition of an observant saw doctor, the sustained attention of a dedicated quality control person, or an isolated finding from decades before. Here we will consider three examples of this process at work. Each case involved successful management of stresses in the tool or in the work piece: 1) Increasing feed rate in band sawing: managing stress imposed on the saw; 2) Improving surface quality and process reliability in cross-cutting; and 3) Improving cutting accuracy and product value in circular sawing. |
| 10:00-10:30 | Coffee break |
| 10:30-11:15 | Bandmills: Bandmill Alignment; High Speed Bandmills; Correct Guide Pressure; Active Guides; Canter Alignment Dr. John Taylor, Sawmilling Group, Lumber Manufacturing, FP Innovations, Forintek Division, Vancouver, B.C., Canada The bandsaw is still one of the best saws for high-speed, thin-kerf, mismatch free, cutting. This is evident in most new double length infeed log breakdown canter lines, where the saws of choice are twin 5-ft or 6-ft bandmills. This presentation includes information collected over many years and questions and discussions are encouraged. |
| 11:15-12:00 | Review of Circular Saw Guides Development Leonard Valadez, Vice President, California Saw & Knife Works, Inc., Tacoma, Washington, USA This talk will review guide design before and after the circular saw guide research that was conducted in the late '70's and early 80's. This discussion will cover guide lubrication aspects as well as guide saw stability in curve sawing applications. |
| 12:00-1:00 | Lunch break |
| 1:00-1:45 | On-line Lumber Size Control Using SizeCheck® Program Earl Barker, President, EB Associates, Inc., Enumclaw, WA Sawmills need a simple, reliable, and automatic way to monitor their sawing accuracy on a continuous basis. The SizeCheck® program measures every cant and board as it is produced. Data on individual boards in the form of strip charts, histograms, and shift summaries are displayed in real time. Mills report higher lumber quality and grade yield, the ability to use smaller target sizes, and a boost in production due to fewer unscheduled saw changes. |
| 1:45-2:30 | Effect of Side Clearance on Guided Saw Cutting Accuracy Gary Schajer, Professor, Dept. Mechanical Engineering, University of British Columbia, Vancouver, Canada This talk describes an investigation into the significance of tooth side clearance in guided circular saws. Smaller side clearance reduces kerf width, but at the expense of cut-line straightness. The balance between these competing factors is considered and practical recommendations are provided. |
| 2:30-3:00 | Coffee break Demonstration of CSAW software for circular saw calculations. |
| 3:00-3:45 | Bandsaw Tracking: The Effect of Saw Tensioning, Back Crown and Strain
on Sawing Performance Gary Schajer, Professor, Dept. Mechanical Engineering, University of British Columbia, Vancouver, Canada This talk explores the factors that make a saw blade track well and cut accurately on a bandsaw machine. The factors considered include saw tensioning, back crown and strain, as well as wheel crown, taper and cross-line. The influences of these various factors on each other will also be described. |
| 3:45-4:15 | Safety Issues in Primary Wood Industry: Review of Causes of Accidents in
Sawmills and How They Can Be Avoided Ryszard Szymani Accidents at the bandsaw headrig, board edger and location of machine operator; and accident during trim saw maintenance in a sawmill will be described and general discussion will follow how these accidents happened and how they could have been avoided. Included in the discussion will be machine design, machine guarding, machine operator location, and latest pictorial warning signs. This presentation is based on 30 years of experience in accident investigation in the primary and secondary wood industry and serving as an Safety Consultant on the ANSI 0.01 Safety Requirements for Wodworking Machinery Committee (1983-1997). |
| 4:15-4:25 | Questions and Answers |
| 4:25-4:30 | Closing Remarks Ryszard Szymani |
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________________________________________________________
Wood Machining Institute
P.O. Box 476
Berkeley, CA 94701 USA
Tel: 1-925-943-5240; Fax: 1-925-945-0947
e-mail:
szymani@woodmachining.com
www.woodmachining.com