Manufacturing analysis using computer flow simulation has been applied successfully in pilot projects to several Alberta value-added wood products companies in the sectors of re-manufacturing and furniture manufacturing. This project continues these pilot projects examining the application and potential benefit in manufactured/prefab homes. An Alberta manufactured/prefab home manufacturer was selected for this project. The wall-line was chosen for this study. The study was accomplished through detailed observations and data collection, which identified several bottlenecks that included the framing table, squaring table and the linear configuration of the line. From observations, the squaring table was labour intensive and the material handling equipment was quite slow. At the framing table, the stud grade being used contained many twisted and bowed boards, which required additional time to align and fasten the studs. Lastly, the single-line configuration created bottlenecks during the transition from sheathed and unsheathed products. From observations and discussions with staff, potential improvement scenarios were developed. Simulation models were developed for each of these scenarios to evaluate their effectiveness and return on investment. The scenarios examined were: affect of panel sheathing ratio, improving efficiency at the squaring table, improving efficiency at the framing table, addition of a branch-line for unsheathed products and the addition of the branch-line in combination with increased efficiency at the framing table. The implementation of pre-cut OSB panels was simulated to reduce processing times at the squaring table by 30%, which increases throughput by 15%. The addition of a branch-line for unsheathed products showed a potential production increase of 10.8%. However, the simulation models also showed that the framing table could not maintain a consistent supply to the squaring table. The use of a higher stud grade was modelled showing a potential production improvement of 17.5%. As a result, the potential benefits in this particular wood products business demonstrates that computer flow simulations can be applied to Manufactured/Prefab Home manufacturers and may potentially have further implications in other similar Alberta value-added industries.
Particleboard (PB) is an important panelboard material used in value-added wood products. Its advantage is its low cost but its disadvantage is that its surface quality degrades when machined. Extensive research has been conducted in PB machining, the key aspects of which are highlighted in this report. Research to improve machineability has focused on the PB material, cutting tool and process parameters. Work on the PB material has mainly focused on reducing tool wear and, more recently, on PB micro-scale behaviour during cutting. This work has led to the reduction of impurities in PB. Work on the cutting tool has focused on tool geometry and tool material improvement. This has led to the development of specialized bevel sawtooth profiles that reduce edge chipping. Tungsten carbide and polycrystalline diamond have been extensively tested and are the most widely recommended tool materials for PB. Work on the cutting parameters has focused on developing operating guidelines as well as on optimizing the milling angle relative to the workpiece. A cone-face milling tool has been designed to reduce edge chipping in the edge banding process. Research and testing has also led to general guidelines for parameters such as feed per tooth. The effect of PB material, tool and cutting parameters is commonly measured by the change in cutting force and surface quality. A standard measurement method for melamine edge chipping and an approximate method of calculating cutting force have been developed. Although many developments in PB machining have been made, several key industrial machining process areas still require research. These include machinery set-up, process optimization and troubleshooting. There is an urgent need to account for the variability and micro properties of PB in the machining process. If successful, this should increase the reliability of research results and increase the industrial applicability of the work.
Particleboard (PB) is a widely used panel material for value-added applications. Unfortunately, machining problems can sometimes occur in practice that are time consuming and costly to resolve. The main reasons are the wide range of PB characteristics and excessive reliance on intuition and experience in PB use. Previous research on PB cutting has assumed plane isotropic properties and applied cutting theories from other materials for modeling. Unfortunately, the complex and non-uniform structure of PB at a microscopic scale is not accounted for in these approaches. A practical model requires that these factors be included. A PB cutting model is under development to increase the understanding of PB behaviour and guide the set-up and troubleshooting of machinery. The experimental results described in this report examine the effect of chip thickness and particle size on PB cutting behaviour. When the chip formation process is examined over a continuous range, PB displays unique cutting behaviour. First, the chip thickness can deviate from the theoretical value as a result of fractures that form in the PB below the tool path. These sporadic deviations also affect the chip thickness of subsequent cuts. Second, the chip formation process displays three distinct phases: Rub, Scrape and Cohesive Chip. No cutting occurs in the Rub phase. Third, the particle size also has a significant effect on PB cutting behaviour. The Rub and Scrape phases in chip formation tend to increase in duration with particle size while the Cohesive Chip phase tends to decrease. In addition, the cutting force and the amplitude of its fluctuation about an average tend to increase with the particle size.
The objective of this research work is to identify the critical parameters that are important during the manufacture of particleboard, and during subsequent machining. Particleboard manufacture and subsequent end-use can then be matched to each other to achieve the best results. These processing advances will directly improve product quality and the economic competitiveness of value-added manufacturers who use particleboard.
A quality control system ensures that lumber is manufactured to the correct size and highest grade. The system currently used by most sawmills is labour intensive and as a result, limits the frequency of quality monitoring. Automatic in-line systems have been developed but found to be inaccurate and produce false alarms. UBC researchers have identified the problem with automatic systems to be faulty statistical assumptions and poor design and is developing a new statistical method and scanning system that is more reliable and accurate. Forintek Canada Corp. is developling a defect recognition system based on the new UBC system. The UBC system utilizes single point laser sensors that scan the surface of lumber along its length. This provides the potential for detecting eleven common machining and machinery related lumber defects. Washboarding, saw marks, roll marks, spike marks and scallop are repetitive defects that can potentially be detected by the system. Wane, taper, snipe, tear out and wedge are non-repetitive defects that may also be identifiable. Fast Fourier Transform (FFT) and other algorithms are being developed to detect repetitive defects. Each defect produces a FFT frequency spectrum that can be used as a fingerprint for identification. Development of algorithms to diagnose non-repetitive defects will begin in the near future.
A wear test was conducted on two Cermet and one tungsten carbide tool materials when cutting green western red cedar. Three 4.35-inch diameter sawblades were custom manufactured for the KT125 (Cermet), KT195 (Cermet) and K3030C (tungsten carbide) tool materials with a 0.140-inch kerf. The Cermets were successfully braised using a copper interface between the saw tip and saw body, high silver content solder and limited heat application. The cutting test was conducted on a Delta vertical single-spindle shaper using a bite of 0.026 inches. Wear measurements by impression method were taken at 0, 5000, 10000, 15000 and 20000 lineal feet of cutting. The KT125 grade Cermet fractured early in the test after 140 lineal feet of cutting and would not be considered appropriate for green western red cedar. At the completion of the test, the tungsten carbide tool material had reached the end of its useful life. Measurements showed substantial wear. The KT125, on the other hand, showed significantly lower wear and remained in a running condition after 20000 lineal feet of cutting. Since the KT125 did not reach its end of life, it is difficult to estimate its wear advantage over the tungsten carbide. Based on the wear rate measurements of recession, width and diameter and making several comparative assumptions, a preliminary estimate of the wear advantage may be obtained. It is projected that the wear advantage of KT195 is 1.7 to 4 times beyond that of K3030C under the conditions in this test. Validation of this wear advantage and the determination of the optimum operating conditions for Cermets will require more extensive testing and sawmill trials.
Forintek conducted a series of tests to investigate the properties of five indigenous wood species: trembling aspen, Jack pine, black spruce, white spruce and white birch. The relative performance of these wood species in machining, fastener withdrawal, and finishing are compared in this guide.
The results are relative and not absolute. With this guide, you should be able to compare the performances between these five species and make informed decisions in choosing a species most suited to your operation. It will also allow you to identify potential problems and make rapid changes to machine and process set-ups to suit each species.
Lumber remanufacturing in Alberta plays an important role in increasing the value of the province's wood fibre resource before it is exported, but it is facing challenges on several fronts. The high value of the Canadian dollar, softwood export taxes, and changing market demands all place pressures on producers. One Alberta lumber remanufacturer has responded to these challenges by re-tooling their plant with a state-of-the-art automated line. A payback period of 1.7 years was estimated based on early data. The new line removes most manual material handling by performing automatic grading, cutting, sorting, material movement, and stacking of products, and has cut the labour requirement of the lines it replaced from 31 workers per shift down to 14. Changeovers are done in 10 minutes or less, rather than the 30-90 minutes required for the old lines. Removal of the old lines and installation of the new one was completed in the course of approximately six weeks. The new line is now in its final implementation phase. Ramping up of production to its predicted amount of at least 170 000 fbm per shift has taken longer than planned, due to the plant's unfamiliarity with the new technology. The experiences of this company are shared to show the potential benefits and pitfalls that may be encountered when undertaking such an upgrade.
The objective of this publication is to compare the performance of five common Saskatchewan wood species in typical secondary wood processing applications. The machining, fastener withdrawal, and finishing properties of trembling aspen, black spruce, white spruce, western white birch and jack pine are presented. The American Society for Testing and Materials test procedures used as a guideline were D-1666 and D-1761 for the machining and fastener withdrawal tests respectively; and D-3359 and D-4541 for the finish coating adhesion test. The machining tests included planing, sanding, shaping, mortising, drilling and turning. In these tests, the resulting machined surfaces were examined for machining-related defects. The fastener withdrawal tests measured the mean force required to withdraw nail and screw type fasteners. The finishing tests determined the adhesion of a number of typical commercially available coatings to each of the wood species and the appearance attributes of a broad range of furniture-type production finishes. All of the species performed well in the tests but some of the results were surprising, as comparisons revealed relative strengths and weaknesses across species.