## 4 The Qualification Procedure for AM Components  
Additive manufacturing techniques produce exceptional microstructure and mechanical properties, which is different than those of traditional manufacturing techniques [34]. Many qualification procedures and standards are already developed for conventional manufacturing methods that are used as a base for developing qualifying methods for additively manufactured components. Using these available qualification procedures helps to enhance consistency and to ensure that the qualification procedure for AM components complies with other available codes and standards. Figure 2 indicates the qualification sequence for AM process. According to Figure 2, the qualification process starts by assessing the technology and raw material (powder), and continues with evaluating the manufacturing procedure, finally ending by qualifying the material performance for the intended application. As is clear, some qualification activities are required to be performed before the build job begins. Table 2 summarizes the most important parameters which should be assessed before the start of build job. After the pre-processing step is successfully qualified, the build job starts. In this step, the subject matter engineer must carefully define the processing parameters to obtain desired microstructure and material properties.  
During the qualification process, all steps should be recorded in the manufacturing procedure specification (MPS) document of the project. This is critical for production repeatability and reliability, as the quality of the AM parts substantially relies on process controls. Here, the qualification procedure works as a formal validation and approval of the process controls and ensures that the manufacturing procedure is feasible. The main concerns in the manufacturing procedure qualification sequence are presented in Table 3.  
Figure 1: Schematic of selective laser sintering (SLS) [30].  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Qualification Step** & **Main Parameters to Be Controlled** \\ \hline \multirow{4}{*}{Qualification of raw material} & Powder handling and storage, verification of virgin powder, usage, reprocessing, reuse limits and controls, powder chemistry and morphology. \\  & Process type, machine type, calibration requirements, complete documentation of operating condition, Diagnosis of equipment, routine controls. \\  & Qualify the probability of detection and the capabilities of the used in-situ monitoring techniques. \\ \hline \hline \end{tabular}
\end{table}
Table 2: Qualification parameters before the start of the build job.  
Figure 2: Five qualification sequences for additively manufactured parts.  
Qualification of the performance is the most critical quality control stand. This step simultaneously ensures that the raw material, equipment, parts, and process are in a manner that the final product fits the customer's requirements (Table 4). The qualification process may include both inspection and destructive or non-destructive test methods.  
The types and number of required tests vary on component criticality. In the offshore oil and gas industry, the performance test types normally include metallurgical, mechanical, and corrosion tests. The test result variation can be compared within one build or between several builds.