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1.1 This guide illustrates a test specimen geometry and testing protocol that can be used to assess the quality of a metal powder bed fusion build cycle as it could be affected by major system errors (for example, corrupted calibration, disrupted inert gas flow, laser wear) severely affecting the quality of materials fabricated by laser beam powder bed fusion (PBF-LB).

1.2 This method is designed to interrupt the manufacturing process if poor material quality is identified through go/no-go torque/angle of twist measurements of witness coupons after each fabrication.

1.3 Units—The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this guide.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

5.1 This guide describes the use of torque and angle-of-twist data as a preliminary acceptance criteria for a production run utilizing a previously qualified AM process through periodical or continuous evaluation. A torsion device (for example, torque wrench, instrumented lathe with torque readout) is used to break strategically placed torque specimens within the build volume in the as-built state to provide evidence of build health. If a round of tests from a production run is determined to fall outside of some criteria (for example: 3 standard deviations from the mean or other user defined criteria), additional qualification procedures should be performed to ensure the AM machine or process health are acceptable.

5.2 This guide is not intended to replace rigorous qualification procedures and should only be considered as a preliminary acceptance criterion to increase confidence that an AM machine or process has not been significantly compromised.