Thermographic Characterization of Feal Green Sheet

Abstract

INTRODUCTIONThe automotive, aerospace, medical, and electronic industries all now use components derived from powder metallurgy. In many instances, this manufacturing approach can provide parts and stock materials of higher quality and reliability than those obtained using other manufacturing techniques, which contributes directly to the reliability of the products in which they are used. As the market for powder metal parts continues to grow, suppliers are seeking new means to monitor, control and optimize powder metallurgy processes. The focus of this work is the nondestructive evaluation of thin rolled iron aluminide alloy using thermographic techniques designed for quality control during manufacturing [1]. While the formation of products from powder metallurgy can be quite complex, the typical process can divided into four stages. In the first stage, powder metal constituents are mixed with a binder and/or solvent. In the second stage, intermediate products-commonly referred to as green parts-are formed under pressure. The third stage is the removal of the binder and sintering of the metal particles into a solid structure. A fourth stage involving machining or forming is sometimes required. Each of these stages usually has several intermediate steps and each step exhibits characteristic defect morphologies and underlying formation mechanisms. The guiding principle in minimizing the impact of these flaws (with the goal of zero defects) is to identify the most significant flaws as early in the process as possible. Early detection may provide the opportunity to correct the defect downstream in the process. Alternatively, if the flaw cannot be repaired, the defective part can be removed from the process before disrupting product flow or investing process resources in a bad part. It is in this context that the development of technologies that detect and quantify the quality of intermediate and final products will have a significant impact on the growth of future applications of powder technology. The goal of this research is a non-contact, real-time method of inspecting 100% of the green sheet produced by an existing industrial process.