Damage detection in load-bearing additive manufacturing components through use of high-frequency ultrasonic waves

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Damage detection and health monitoring of load-bearing components have been always prime concern for designers and manufacturers. One of modern processes used for manufacturing of metallic and non-metallic parts is additive manufacturing (AM), also referred to as three-dimensional printing or rapid prototyping. In an additive manufacturing process, a computer program directs a scanner to deposit the material precisely at desired spots to build up the final product layer by layer. This makes it possible to produce objects with complex geometries relatively easier and at an affordable cost. The material could be metal, plastic or ceramic which is melted by an energy source such as laser beam, arc, electron beam or ultrasound. The absence of defects in AM components is critically important, particularly if implanted in human body as a prosthesis. For prostheses, such as knee joint, the product must be defect-free. The detection and monitoring of defects growing under repeated loads necessitates to employ advanced non-destructive testing (NDT) techniques, which do not damage the serviceability of the product. In this project, a unique phased array ultrasonic testing (PAUT) method will be employed. The PAUT has been in use for several years by industries with limited frequency of maximum 10 MHz. This level of frequency is not high enough to assure detection of very small defects/cracks in load-bearing AM products. The present study offers the use of phased array ultrasonic testing method with higher frequencies, as high as 50 MHz, to detect and monitor AM manufactured prostheses components under repeated loads. The method enables defect detection and cracking of few microns over early stages of loading addressing shortcomings of other NDT techniques. The outcome of this project upon completion is to safely manufacture additive components, to minimize damage in the manufactured parts, and to promote risk-free and reliable biomedical products including knee joint prosthesis in service. It is also expected that the mutual collaboration between Ryerson University and FUJIFILM VisualSonics Inc. expands over longer terms through this NSERC engage proposal.