Non-Contact Measurements for Industrial Quality Control

拟议的研究旨在开发改进的方法，用于工业产品和工艺的非接触式测试和质量控制。此类技术很有吸引力，因为它们对生产流程的影响最小。它们可以提供实时信息，并允许对材料质量和过程控制做出快速决策。为了突出重点，我从非接触式测试在木材工业中的两个应用的角度制定了我的研究计划，但实际应用远远超出了这一范围。拟议的工作扩展和建立在木材工业中的材料质量控制的非接触式光学和X射线传感器的发展先前的研究。 木材纹理角度测量 为了在国际市场上有效竞争，加拿大锯木厂必须从现有的原材料中生产出最高价值的产品。对于建筑产品，木材强度是主要关注点。然而，木材的大量变异性对强度评估提出了严峻的挑战，因此质量控制变得非常保守。这种方法虽然安全性好，但严重浪费了大量的高价值材料。 木材的强度直接取决于纹理方向。大约15度的偏差。木材强度减半。因此，纹理角是一个非常有效的木材强度指标。现有的测量方法是有限的，因为它们只能测量表面（面内）晶粒角度，而不能测量俯冲（面外）角度。这里探讨的定向反射方法是独一无二的，因为它可以测量两个角度。该方法利用木材表面的特性，优先在垂直于纹理的平面内反射入射光。在所提出的工作中，一种新的几何形状的测量装置进行了探索，使晶粒角度轮廓扫描要在很宽的晶粒角度范围内。 工业锯片张紧测量 在锯木厂，木材原材料消耗约75%的总成本。因此，非常重要的是，工业锯应尽可能薄，以产生最少的锯屑浪费，同时也要足够厚，以直线切割。允许的锯片厚度可以通过由称为“张紧”的过程在锯体中引入应力来进一步减小。为了确定有效的加工条件，有必要单独评估每个锯。该评估涉及观察非常小的形状变化，这些变化难以以一致的方式测量。本文提出用电子散斑干涉法（ESPI）测量锯片微小变形。剪切电子散斑干涉技术是特别适合的，因为它测量表面斜率，因此可以更好地检测局部变形的细节。

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.