## 1 Introduction
[PERSON] compares conventional drilling with two other strategies (helical milling and contouring milling), obtaining greater diameter accuracy, less angular deviation and burr-free deviation in helical milling [16]. [PERSON] [17] performs a mathematical decomposition of the movement carried out to facilitate its study, relating the material that is milled and the material drilled during an operation according to two independent parameters (hole and tool diameter), and defining a new \"G\" parameter, as the quotient between milled material and drilled, deducing that this ratio is independent of the axial velocity, as verified in Equation (1):  
\[G=\frac{V_{1}}{V_{2}}=\left(\frac{D_{B}^{2}-D_{w}^{2}}{D_{W}^{2}}\right) \tag{1}\]  
where \(V_{1}\) and \(V_{2}\) are the volumes of milled and drilled material respectively, \(D_{B}\) is the diameter of the hole and \(D_{w}\) is the diameter of the tool. Another work found that for aluminium alloy, down milling and the use of MQL (minimum quantity of lubricant) produces higher burrs than in up and dry milling [9]. [PERSON] makes a comparison between conventional drilling and helical milling, concluding that the cutting forces in helical milling are about 1/5 of the forces in drilling, tool wear is improved, and all machining precision indicators are better in helical milling, especially burr formation [18]. On the other hand, the properties shown by these elements when in service are influenced by the machining processes used, due to the impact on the surface integrity of the components. The concept of surface integrity includes both exterior and internal defects. The first can be microdefects where the concepts of surface quality and waviness are included, or macrodefects that include the concepts of shape. The internal defects are located in the sub-surface producing alterations that include microstructural transformations, heat-affected areas, hardness, residual stresses etc. [19; 20; 21]. In these types of component, fatigue strength is one of the most important properties, and where residual stresses have an important role. The effect of the helical milling strategy on the residual stresses and fatigue life of the machined part has always conditioned the choice of more traditional methods. However, several studies have shown that the influence of the helical milling process on the generation of residual stresses can be beneficial by inducing so-called \"good\" stresses (compressive residual stresses) and lead to improvedperformance in fatigue tests. [PERSON] et al. in their investigations [12; 22] compared among other characteristics, the residual stresses and fatigue life generated by conventional drilling and helical milling processes. These studies concluded that the elements machined with helical milling showed a longer fatigue life, causing, among other factors, the induced stresses to be compressive stresses. On the other hand, [PERSON] et al. in their study [23], carried out an analytical model to predict the residual stresses induced by helical milling, finding a good relationship between the theoretical models and the experimental results, and compression stresses were obtained in all cases. In this context, and recognizing the importance of the drilling process before assembly operations, helical milling is positioned as an alternative to conventional drilling where potentially advantageous characteristics are identified. However, the correlation between the variables associated with hole quality and the parameters associated with kinematics for difficult-to-machine materials has rarely been studied. Therefore, the objective of this study is to identify the sensitivity and the main trends of the properties that define the quality of the holes in relation to the kinematic parameters of the helical milling process in the UNS R56400 alloy. During the study, a lack of consensus was detected among the different researchers over identifying the source of problems that generate ambiguity in the interpretation of the kinematic parameters of the helical milling process.