A D V A N C E D M A T E R I A L S & P R O C E S S E S | J U L Y / A U G U S T 2 0 2 2 2 6 Another area of concern with AM is the directionality of heat subtraction from the forming part. Directionality in cooling yields increased directionality in grain growth, and, as a result, increased anisotropy in strength and ductility. Anisotropy in mechanical properties is acceptable when understood and is ideally optimized in design, but it is impossible to understate the importance of testing in the directions that correspond to which way the part will be stressed in service. Periodic checks to verify repeatability are similarly necessary, especially in the high stakes medical device, aerospace structures, and automotive parts industries. DATA MANAGEMENT While increasing the specimen quantity in a testing regimen is one way to garner more qualifying information, it’s also beneficial to apply methods that deliver more data for each specimen tested. Digital image correlation (DIC) is one tool that can be used to identify strain concentrations across the gauge length, increasing the field of observed behavior from a static test alone. While also useful in conventional applications, DIC is especially useful in AM part and process qualification where greater variability is expected. The combined effect of increased specimen quantities and increased values being measured may seem daunting for legacy data management systems; however, advancements in data handling have risen to the occasion. DIC in conjunction with data management software significantly reduces the workload of evaluating more locations from more specimens and ultimately enabling greater laboratory throughput. As additive manufacturing becomes increasingly viable for applications that are highly regulated and require predictable mechanical properties, it’s important not to let the inherent challenges of this production method detract from the valuable advantages of the technology. While rapid solidification and directional heat subtraction raise concerns for internal quality, they are also fundamental to this process that enables the engineering of complex, optimized, and individualized geometries. In conjunction with well-designed process monitoring and control, increased testing and modern data management provide the critical infrastructure for qualification and certification of a new generation of AM metal components. ~AM&P For more information: Dean Lovewell, metals market manager, Instron, 825 University Ave., Norwood, MA 02062, 781.575.5000, dean_lovewell@instron. com, www.instron.com. AM testing generates enormous datasets that can be difficult tomanage. The workload can be greatly reduced by modern software infrastructure, which enables the quick search, display, and analysis of results over time, across multiple samples and test systems.
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