Non-Contact Measurements for Industrial Quality Control

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The proposed research aims to develop improved methods for non-contact testing and quality control of industrial products and processes. Such techniques are attractive because they minimally impact production flow. They can give real-time information and allow prompt decision making for material quality and process control. To give a specific focus, I have framed my research program from the perspective of two applications of non-contact testing in the wood industry, but practical applications reach substantially beyond. The proposed work extends and builds on prior research on the development of non-contacting optical and X-ray sensors for material quality control in the wood industry.******LUMBER GRAIN ANGLE MEASUREMENT***To compete effectively in the international market, Canadian sawmills must produce the highest value products from the available raw material. For construction products, wood strength is a primary focus. However, the substantial variability of wood presents a serious challenge to strength assessments, so quality control becomes very conservative. While of good safety, this approach seriously wastes a lot of high value material.******The strength of wood depends directly on grain direction. A deviation of about 15 deg. halves wood strength. Consequently, grain angle is a very effective wood strength indicator. Established measurement methods are limited because they can measure only the surface (in-plane) grain angle, but not the diving (out-of-plane) angle. The directional reflection method explored here is unique in that it can measure both angles. The method exploits the characteristic of a wood surface to reflect incident light preferentially in a plane perpendicular to the grain. In the proposed work, a measurement device of novel geometry is explored to enable grain angle profile scans to be made over a wide range of grain angles.******INDUSTRIAL SAWBLADE TENSIONING MEASUREMENT***In sawmills, the wood raw material consumes about 75% of total costs. Thus, it is very important that industrial saws should be as thin as possible to produce minimum sawdust waste, while also being thick enough to cut in a straight line. The allowable sawblade thickness can be further reduced by inducing stresses into the saw body by a process called "tensioning". To determine effective processing conditions, it is necessary to assess each saw individually. This assessment involves observing very small shape changes that are difficult to measure in a consistent way. Electronic Speckle Pattern Interferometry (ESPI) is proposed here as a means of measuring the small deformations in sawblades. The shearographic ESPI technique is particularly well suited because it measures surface slope and so can better detect local deformation details.********