*2.2. Operation Time Estimation*

In this subsection, the various methods for the calculation of the operation times for each of the five steps of production are going to be presented, with each of these being divided into one subsubsection. The total operation time estimation is obtained by adding the estimated values obtained for each of the production steps.

#### 2.2.1. Operation Time Estimation: CAD 2D/3D

For the estimation of total part production time, the 2D and 3D drawings must be considered. These are a necessity for part production and are not always provided by the client, meaning that in some cases these must be produced. The configuration of the cost estimation tool was made considering the types of drawings for milled parts received. Base times were attributed for 2D and 3D drawings, and are presented in Table 3.


**Table 3.** Base times for the steps regarding the CAD preparation of the parts.

These base times will be influenced by the part's complexity, which will be explained in more detail in Section 2.2.2.
