Today's machine centres are being increasingly automated but often operate as a collection of isolated machines run by a variety of computer systems. Clearly, such heterogeneous computing and control environments present a formidable barrier to the problem of interoperability. Already there are vendors that provide a partial solution to the problem, since they provide methods of interoperability only between machines that they supply. Vendor-specific methodologies are in general proprietary, and do not inter-operate with any other vendor's equipment. What's needed to facilitate widespread machine-to-machine data exchange is a universal methodology to connect to optimizer data, or any data for that matter, with plug-and-play simplicity. In order to enable enhanced data availability and also to lay the foundations for the evolution of process monitoring and control in the sawmilling industry, this project was undertaken to create a common methodology for vendor-neutral data exchange between machine centres, process monitoring and control systems, and business systems.
A task forceª, with members drawn from sawmilling and equipment vendor companies, selected the well-established specifications for data exchange published by the OPC Foundation, a consortium of companies committed to universal data exchange in industry. While these specifications specify standards-based methods for data exchange, the task force recognized that there was an additional layer required to create standard plug-and-play access to sawmill optimizers. This additional standardization layer specifies exactly what data is made available per optimizer type. After testing these ideas for primary breakdown optimizers and PLCs in a sawmill-based pilot project, the task force unanimously adopted the OPC specification and our per-optimizer layer as a practical standard for data exchange in the sawmilling industry.
Given this initial success, however, there needs to be a continuing effort to ensure that the evolving sawmill standards eventually are applied to all optimizer types, and that sawmill managers and executives are aware of their benefits. Continuing effort must ensure that multi-vendor support per optimizer type does not result in tag list fragmentation which would undermine the benefits of standards. The methodologies adopted during this project will never become standard in the sawmilling industry unless the majority of sawmillers demand the standard OPC optimizer interfaces defined by this project.
ª In this document, “task force” is used interchangeably with “working group”. On 21 March 2002, a standards committee was struck from task force members, but soon lost its meaning when the task force adopted an email list approach to collaboration. The email list was much more inclusive and therefore much larger, and became the defacto “working group”. By project end, the working group consisted of 40 members.
This report presents the results of the first stage of an investigation into the feasibility of developing a machine capable of automatically tensioning a bandsaw blade. The present work involves an experimental and analytical investigation of the effects of roll tensioning upon the cutting performance of the bandsaw. In order to understand the role of roll tensioning its effects on internal stress distribution, torsional and lateral natural frequencies and stiffness of the blade have been investigated. The results of strain measurements induced during different rolling patterns and with different thickness of plate and differing rolling pressures are presented and an analytical explanation of the results is given. Experimental results showing how the stiffness of the blade and its natural frequencies are affected by the roll tensioning are also presented. An accurate analytical model that relates the rolling pattern to the lateral stiffness has not been found. Cutting tests have been conducted in which the performance of a blade with no tension is compared with a blade with different levels of tensioning. The results of these tests are presented and indicate that the relationship between cutting accuracy and tensioning is very subtle.
Recent advances in scanning technology have enabled the detection of surface defects in green boards. This report is the second phase of a project that was initiated to investigate the benefits of surface defect scanning (grade scanning) on the value of lumber that can be recovered from optimized edgers. The first study focused on BC Interior mills and found that little or no potential increase was available. In this study, the benefits for mills processing large logs into high value products (e.g. BC Coastal sawmills) were investigated. Sixty-six hemlock cants were evaluated, with cant widths from 12 to 27 inches - large enough to allow multiple sawing solutions. After a sawing solution was generated for each cant by an optimized shifting-saw gang edger, using only profile scanned data, a grader, taking visible defects into account, proposed alternate sawing solutions. The values of all sawing solutions were calculated and for 76% of the cants, a sawing solution proposed by the grader was more valuable than the one generated by the optimizer.
The study found that an average increase of 29% in the value of large cants was available when edging decisions took surface defects into account, in comparison with the value resulting from optimization based on cant profile alone. However, it should be noted that the accurancy of vision systems will likely be less than that of a human grader so the actual gains will likely be somewhat lower.
Le rapport présente une carte routière traçant les grandes lignes d'une stratégie d'innovation technologique, de recherche et de développement, ainsi que de transfert technologique pour les opérations forestières canadiennes au cours de la prochaine décennie. La carte identifie les points de départ et d'arrivée, discute des forces motrices, décrit les occasions favorables à des améliorations technologiques et donne des recommandations sur la meilleure route à choisir pour l'avenir.