Three classes of benchmark test have been defined. Class 1 and class 2 benchmark tests will likely be included in the first round/conference with class 3 benchmarks added in later years.
Class 1 benchmark test
Intent: Provide rigorous data for the development of quantitative simulation models for the entire AM process, from material feedstock to finished parts. An extension to full life cycle modeling is provided by the class 3 benchmark tests.
Conduct rigorously defined and executed AM builds using fully characterized feedstock, open architecture machines with in situ process monitoring (as available), and ex situ characterization. All specifications and characterization plans will be made public, allowing simulation modelers to model any aspect of the problem they like, with detailed knowledge about the starting material, what will be built, how it will be built, what will be measured, and how it will be measured. Post processing (e.g. annealing, hot isostatic pressing, vapor smoothing, tumbling, machining) of the as-built specimens may also be included. To help coordinate efforts, some specific simulation modeling challenges will be specified. While modelers are attempting to predict the measurement results, the people/organizations that helped design each specific benchmark test (members of the Benchmark Test Committees) will carry out the specified builds and measurements. If possible, builds using multiple machines with comparable processing characteristics will be used to explore machine-to-machine variability. Modeling results will be submitted by some deadline before the conference and the measurement results will then be made public. All results and comparisons will be discussed at the conference in dedicated sessions with discussion periods to discuss what worked, what didn’t work, and how to improve the predictions and measurements.
Class 2 benchmark test
Intent: To accelerate development of innovative build strategies for difficult geometries such as overhangs, cantilevers, and other unsupported structures.
Define a specific challenging AM geometry to be built using a specified composition and any AM method. This may include shapes with overhangs, cantilevers, etc. AM builders will attempt to produce the specified shape and will submit their entries to the benchmark test committee for measurement. The benchmark test committee may set limits on the number of specimens that can be submitted. Some of the build geometries may be coordinated with standard test structures under consideration by the joint ASTM F42 + ISO/TC 261 committees. Although the initial emphasis will probably be just geometrical tolerance, later class 2 benchmark tests may include additional properties such as surface roughness, modulus, directional strength under different loading conditions, creep behavior, etc.
Class 3 benchmark test
Intent: Part qualification requires assurance that a manufactured part will perform within its design specifications. The key factor in this benchmark test is functional performance. This may include both performance within a harsh environment (creep, fatigue, corrosion, stress corrosion cracking, impact resistance, etc.) and multifaceted performance metrics (high stiffness with low average density, combination of strength and thermal conductivity, etc.).
Define an overall specimen geometry, material class, and performance metric. All test procedures used to characterize the submitted specimens will be described. AM builders will attempt to produce an acceptable test part, usually related to some common functional requirement. Completed parts will be submitted to the benchmark test committee for evaluation using the announced methods and criteria.