AS ISO ASTM 52911.1:2021 pdf free.Additive manufacturing一Design Part 1: Laser-based powder bed fusion of metals.
5 Characteristics of powder bed fusion (PBF) processes 5.1 General Consideration shall be given to the specific characteristics of the manufacturing process used in order to optimize the design of a part. Examples of the features of AM processes which need to be taken into consideration during the design and process planning stages are listed in 5.2 to 5.8. With regards to metal processing, a distinction can be made between, for example, laser-based PBF (applied for metals and polymers) and electron beam-based PBF (applied for metals only). Polymers PBF uses, in almost every case, low-power lasers to sinter polymer powders together. As with polymer powders PBF, metals PBF includes varying processing techniques. Unlike polymers, metals PBF often requires the addition of support structures (see 6.4.3). Metals PBF processes may use low- power lasers to bind powder particles by only melting the surface of the powder particles or high-power (approximately 200 W to 1 kW) beams to fully melt and fuse the powder particles together. Electron beam-based melting and laser-based melting have similar capabilities, although the beam energy transferred from the electron beam to the metal is of a higher intensity and the process most commonly operates at higher temperatures than the laser counterpart, therefore typically also supporting faster build rates at lower resolutions. In general, since the powder bed is preheated and kept close to the melting temperature during the building operation, electron beam processes subject parts to less thermal induced stresses and have faster build rates, but the trade-off often comes with much longer times needed for the build chamber to cool down after the build cycle has been completed, and in general larger minimum feature sizes and greater surface roughness than laser melting. 5.2 Size of the parts The size of the parts is not only limited by the working area/working volume of the PBF-machine. Also, the occurrence of cracks and deformation due to residual stresses can limit the maximum part size. Another important practical factor that can limit the maximum part size is the cost of production having a direct relation to the size and volume of the part. Cost of production can be minimized by choosing part location and build orientation in a way that allows nesting of as many parts as possible. The cost of the volume of powder required to fill the bed should be considered. Powder reuse rules impact this cost significantly. If no reuse is allowed then all powder is scrapped regardless of volume solidified.
AS ISO ASTM 52911.1 pdf download.