## 3 Machinability of AM Ti6 Al4V Alloy
### Qualification of Machined Parts for Assembly  
The AM parts can be machined to precise specifications, making them suitable for prototype applications, one-time parts, and mass production of stock components. The precision and consistency achieved in the machining of these parts enhance the reliability of the final product, which is especially crucial in critical onshore, offshore, medical and transportation applications. As industries often require replacement parts, the demand for machined components continues to grow. Geometrical product specification (GPS) provides guidelines for the qualification processes of profile and surface texture dimensions, ensuring the accuracy of surface roughness measurements [101]. Whenever any part in machinery or equipment suffers wear and tear, or breaks, it can be replaced with a perfectly fitted machined component, hence extending equipment life. Standards and specifications, such as ISO 9001 [104], AS9100, and ISO 13485 [105], set the foundation for defining qualification \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Reference** & **Optimization Method** & **Cutting Environment** & **Cutting Condition** & **Machine Responses** \\ \hline \multirow{4}{*}{[96]} & \multirow{4}{*}{Grey Taguchi} & & \(V=60,80,\) and \(100\) m/min & \multirow{4}{*}{Surface roughness, tool wear, power consumption, and material removal rate.} \\  & & & \(f=0.08,0.16,\) and & & \\  & & & \(0.24\) mm/rev & & \\  & & & \(d=0.2,0.3,\) and \(0.4\) mm & & \\  & & & \(V=50,80,\) and \(100\) m/min & & \\
[102] & Grey relational analysis & & \(MQL\) & \(f=1\) mm/rev & & \\  & based on Taguchi & & \(d=1.5\) mm & & \\  & & & \(V=35,70,\) and \(105\) m/min & & \\
[96] & Grey-Taguchi approach & & Dry & \(f=0.08,\)\(0.12\) and & & \\  & & & \(0.16\) mm/rev & & roughness. \\  & & & & \(d=0.1,\)\(0.2\) and \(0.3\) mm & & \\  & & & \(V=50,100,\) and \(150\) m/min & & \\
[92] & Grey relational analysis, Taguchi & & Dry & \(f=0.12,\)\(0.16\) and & & \\  & analysis, Taguchi & & \(0.20\) mm/rev & & \\  & & & \(d=1,\)\(1.5\) and \(2\) mm & & \\  & & & \(V=140,\) \(224,\) and \(315\) m/min & & \\
[103] & Grey relational analysis, & & \(f=0.051,\) \(0.071\) and & Cutting force temperature & \\  & ANN, and regression & & \(0.102\) mm/rev & & and surface roughness \\  & & & & \(d=0.5,\)\(0.75\) and \(1\) mm & & \\
[57] & Taguchi & Dry & Drilling speed (V) = 20, and & & \\  & & & \(165\) mm/min & & \\  & & & \(V=174,\) \(420,\) and \(930\) m/min & & \\
[96] & Grey relational analysis & & Dry & \(f=0.08,\)\(0.28\) and & & \\  & & & \(0.52\) mm/rev & & \\  & & & \(d=0.4,\)\(0.6\) and \(0.8\) mm & & \\  & & & \(V=250,\)\(500,\)\(750,\)\(1000,\)\(1250,\) & & \\
[68] & Taguchi L\({}_{27}\) (31\({}^{33}\)) & & Dry & \(f=0.1,\)\(0.2,\)\(0.3,\) and & & \\  & & & \(0.4\) mm/rev & & \\  & & & \(d=4.1\) mm & & \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Summary of literature on optimization in the machining of Ti6 Al4V alloy. requirements. It was noticed that a limited number of standards and specifications are present in the AM-process parts for assembly [106]. The qualification process employs both non-destructive and destructive testing methods to verify that components meet the specified quality standards for their intended applications. These methods are crucial for ensuring the safety, reliability, and overall quality of machined parts. The process typically begins with a visual inspection of the machined component, during which the dimensional accuracy is assessed for compliance with ISO designation standards. ISO 13485 was established to qualify the AM Ti6 Al4V alloy for medical implants accepted for applying heart valve frames [107]. EN ISO 3452 and ASTME 1417 present guidelines for detecting a crack on the threads and surface AM hydraulic manifold by dye penetrant [108]. ISO 21920-2:2021 [109] is a proper qualification process that helps in ensuring that machined parts are of the required standards in terms of quality.