AS ISO/ASTM 52902:2021 pdf free.Additive manufacturing – Test artifacts – Geometric capability assessment of additive manufacturing systems.
5.5 Download files
The 3D digital models for standard test artifact geometries can be downloaded in .step format at
https://standards .org/iso/52902/ed-1/en. For a complete list of available files, please see Annex D.
5.6 Discussion of file conversion
When a CAD model is converted to AMF, STL (or any intermediate file format), sufficient fidelity shall be maintained to ensure that the test artifact produced from it fairly reflects the capabilities of the AM system under assessment. The file conversion tolerance selected should ensure that the maximum deviation of the data from the nominal CAD model is less than one quarter and, based on good measurement practice, ideally less than one tenth of the expected accuracy of the AM system being assessed. Currently, most additive manufacturing equipment cannot produce features with a resolution better than 10 pm, therefore CAD models are saved to STL/AMF ensuring at least a 2,5 pm accuracy or better. This is only general guidance and should be confirmed for the specific output system. It is recommended that users check the maximum deviation and record the conversion parameters used, as well as any maximum deviation (chord height and angular tolerance).
Files should not be scaled up or down either during conversion or afterward. Machine correction factors (e.g. offsets, axis scaling, etc.) may be used and should be documented as part of the process specification.
5.7 AMF preferred (with conversion instructions! resolutions)
The AMF file format as defined by ISO/ASTM 52915 is the preferred model format for test artifact geometry representation due to its ability to store high fidelity geometry with embedded units in an intermediate file format.
5.8 Need for test specification and test process
This document forms the basis for the general Test Plan/Specification described in ASTM F2971:2013, Annex Al, element ‘D”, but specifics about its implementation need recording to accurately document the Test Process (element “E” in Annex Al), used for producing the parts as discussed in Clause 6.
5.9 Quantity of test artifacts
For a complete test of machine performance, two things dictate the quantity of the test artifacts produced. First, the Test Specification/Test Process shall ensure a quantity of samples, typically no less than five, so that statistically significant measurements can be made. Second, sufficient coverage (see 5.5) of the build platform needs to be made to account for variations in performance between build locations. Fewer test artifacts with less complete coverage may be used for spot checks or limited demonstrations, such as the example detailed in Annex A. The number of artifacts shall be agreed upon between the buyer and seller and shall permit to perform at least 5 mesurements.
5.10 Position and orientation of test artifacts
As per ASTM F2971:2013, Annex Al, element F, it is recommended to report results in combination with the test artifacts’ build position and orientations according to the convention set forth in ISO/ASTM 52921.AS ISO/ASTM 52902 pdf download.