Surface Characterization of Weathered Wood Using A Laser Scanning System

Most of the existing methods to assess the effect of weathering on wood surfaces have some drawbacks that limit their use to specific tasks. The amount of surface erosion is often used as a measure for the weathering action. The application of a laser scanning system to reproduce surface profiles and to measure weathering erosion was tested on various samples and was found to be a very useful and superior alternative to existing methods. Further improvements of the system used can be made by refinements of the calibration procedures and by more comprehensive profile analyses

Traditional Versus Engineered Abrasives on Material Removal and Surface Quality

Recently, abrasive manufacturers have developed a new generation of tooling denominated Engineered Abrasives, which present a known grit geometry and distribution in contrast to the traditionally random arrangement of minerals. However, this new abrasive has been developed for use on metals and its behavior and performance on wood is still unknown. The objective of this research is to compare the performance of traditional versus engineered abrasives when exposed to different machining conditions on wood. The contributions of this paper include a characterization of the new abrasive on wood machining and a comparison of their performance against traditional abrasives

Parametric Characterization of Peripheral Sanding

The processing and manufacturing of wood products commonly ends in finishing operations with the perceived quality of the product depending mostly on the finishing processes as well as the preceding surface preparation. Consequently, it is of great importance to achieve the best possible surface quality prior to the application of finishes. The objective of this research is to provide the necessary information to understand the effect of key process parameters involved in the peripheral sanding of wood on the resultant surface quality. In this experiment, a linear-trend resistant split-plot design was implemented to evaluate the impact of factor-level combinations of the following input variables: wood species, spindle speed, feed rate, depth of cut, grit size, tooling resilience, and wood grain orientation. The results show grit size, tooling resilience, and wood grain orientation to be significant for all species considered in the study. Feed rate showed significance for white oak and eastern white pine; an d spindle speed was only statistically important for white oak. The surface descriptors that were sensitive to the machining conditions were [R.sub.a], [R.sub.q], and [R.sub.z], while the descriptors [R.sub.sk] and [R.sub.ku] did not show any particular trends

Quantification of Process Parameters in a Wood Sanding Operation

Sanding is one of the most common practices for smoothing surfaces in the woodworking industry. Among the wood machining processes utilized in contoured furniture making, sanding is one of the most skill-based, time-consuming, and expensive operations. Automation of the sanding process has been severely limited by the lack of information about the effect of key process parameters in the sanding operation and their interactions. The objective of this study was to provide information on the relationships between the key input variables and material removal rate and resultant surface roughness. In this experiment, a randomized full-factorial design with local control was implemented to evaluate the impact of factor-level combinations of the following input variables: wood species, interface pressure, type of abrasive mineral, and sanding orientation. Also, the impact of interactions with respect to the desired quality characteristics of the finished workpiece was assessed

Machining-Induced Subsurface Damage of Wood

As wood is machined, characteristic chip formation mechanisms take place while the workpiece is exposed to severe, but very localized, forces. The result is deformation of the material, concentrated in a narrow zone usually called the shear plane or shear zone. This widely studied deformation/fracture process is perhaps best described as one of tearing. In wood, however, some deformations take place in layers located underneath the freshly generated surface by those forces applied during machining. Although this subsurface deformation has been observed in metals, wood is more susceptible to damage under the stresses caused by machining loads, mainly because of structural heterogeneity and varying material properties. The permanent or semi-permanent compression in woods manifests itself mainly by cell deformation, void crushing, or layers of different density invading one another. This deformation will, to some degree, react with certain applications (like water-based finishes and high ambient humidity among others) and spring back, thus adversely affecting the final surface quality. The result can be fiber-pop, fuzzed grain, and undesired variations in the outer surface of the part. This paper presents the results of a microscopy study regarding the subsurface crushing phenomenon. A taxonomy, with the types and extent of this phenomenon, is also proposed

Comparison Between Geometric Shapes of Engineered Abrasives on Material Removal and Surface Quality - Part II

One of the most recent areas of research in the wood industry is engineered abrasives for wood applications. Engineered abrasives have become a very important product of study and form a class of new products, supplied by several suppliers that are not made in the conventional manner of applying individual abrasive grits to a backing. Engineered abrasives, developed for the metal industry, are made by some type of microcasting process with ceramic or abrasive slurries. The result is a grid of abrasive geometric shapes that are very regular. These regular geometric shapes permit a more consistent, predictable, and even performance during sanding process, and open a universe of possibilities of different shapes and materials mixes. However, this new abrasive has been developed for use on metals and its behavior and performance on wood is still unknown. The objective of this research is to compare the performance of different geometric shapes of engineered abrasives when exposed to different machining conditions on wood. The contributions of this paper include a characterization of the new abrasive on wood machining and a comparison of their performance according to different geometric shapes

Article Process Monitoring Evaluation and Implementation for the Wood Abrasive Machining Process

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