AS ISO ASTM 52911.1:2021 pdf free download – Additive manufacturing – Design Part 1: Laser-based powder bed fusion of metals

AS ISO ASTM 52911.1:2021 pdf free download – Additive manufacturing – Design Part 1: Laser-based powder bed fusion of metals.
This document specifies the features of laser-based powder bed fusion of metals (PBF-LB/M) and provides detailed design recommendations.
Some of the fundamental principles are also applicable to other additive manufacturing (AM) processes, provided that due consideration is given to process-specific features.
This document also provides a state of the art review of design guidelines associated with the use of powder bed fusion (P1W) by bringing together relevant knowledge about this process and by extending the scope of ISO/ASTM 52910.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO/ASTM 52900. Additive manufacturing — General prmciples — Fundamentals and vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/ASTM 52900 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http://www .org/obp
— IEC Electropedia: available at http://www.electropedla.org/
3.1
curl effect
thermal and residual stress elfect
dimensional distortion as the printed part cools and solidifies after being built or by poorly evacuated heat Input
downskin area
D
(sub-)area where the normal vector n projection on the z-axis is negative
Note ito entry: See Fiurc 1.
3.3
downskln angle
angle between the plane of the build platform and the downskin area (12) where the value lies between 0° (parallel to the build platform) and 900 (perpendicular to the build platform)
Note ito entry: See Figure 1.
5.7 DImensional, form and positional accuracy
It is not possible to produce the tolerances that can be achieved with conventional tool- based manufacturing processes. For this reason, post-processing can be necessary to meet (customer) requirements. Post-processing may include subtractive manufacturing, surface finishing, thermal processing, or other operations according to ISO/ASTM 52910
In this respect, it is particularly important to be aware of and consider process parameters that influence characteristics of the final part. For example, build orientation to some extent determines the level of accuracy that can be achieved. Directionally dependent (anisotropic) shrinkage of the part can occur due to the layer-wise build-up. As another example, layer-wise consistency can he affected by the location of the part on the build platform.
5.8 Data quallt resolution, representation
The use of AM requires 3D geometric data which is typically represented as a tessellated model, but other representations that can also be used include voxels or sliced layer representations. For tessellated data, files describe the surface geometry of a part as a series of triangular meshes. The vertices of the triangles are delined using the right-hand rule and the normal vector. The STL file format is recognized as the quasi-Industry data exchange Format. Additional formats Include AMF, which Is described In ISO/ASTM 52915. and 3MF. which Is being promoted by an industry consortium led by Microsoft3).
In a tessellation, curved surfaces arc approximated with triangles and the chosen resolution of the tessellation determines the geometric quality of the part to be fabricated. If the resolution is too low. the sides of the triangles defined in the STL file will be visible on the finished surface (i.e. It will appear faceted). however, a tessellation with a resolution that is too high requires a lot of digital storage space and is slow to transfer and handle using processing software. The resolution of a tessellation is generally influenced by a tolerance measure, often called chord height, which describes the maximum deviation of a point on the surface of the part from the triangle (ace. Therefore, smaller tolerance values lead to lower deviations from the actual part surface. A typical rule of thumb is to set the tolerance to be at least 5 times smaller than the resolution of the AM process.