## 2 Materials and Methods  
### Data Collection  
In the experiment, a Busselato automated Computerized Numerical Control (CNC) workstation (model Jet 100) was utilized. This system guaranteed repeatability in the experiment. The drilling process involved using a 12 mm diameter drill from FABA (model WP-01, as shown in Figure 1). The drill operated at a rotational speed of 4500 RPM and advanced at a feed rate of 1.35 m/min, following the recommendations provided by the manufacturer of the drill. The material subjected to the test was a standard 18 mm thick laminated board, commonly used in the furniture industry, produced by the Polish company KRONOPOL (model U 511). The density profile for the chipboard was analyzed with a GreCon DAX device by Fagus-GreCon Green GmbH & Co. KG (Alfeld, Germany), as illustrated in Figure 2. Additional characteristics of the material include a bending modulus of rupture at 15.4 MPa, a bending modulus of elasticity at 2950 MPa, and a Brinell surface hardness (HB) of 2.1. The evaluations of these material properties were conducted in accordance with standards [55; 56], utilizing an Instron 3382 testing apparatus from Instron in Norwood, MA, USA, and a Brinell CV 3000 LDB hardness testing equipment from the Bowers Group located in Camberley, UK, respectively. For an in-depth learning and testing exercise, the condition of drill bits was accurately observed and evaluated using a conventional workshop microscope equipped with a digital camera (Model TM--505; manufactured by Mitutoyo, based in Kawasaki, Japan). In this context, the degree of wear and tear observed on the external corner of the drill bits was considered a direct measure of their condition. This wear (denoted as \(W\)) was quantitatively measured for each of the drill bits' two cutting edges, utilizing the formula provided below:  
\[W=W^{\prime\prime}-W^{\prime} \tag{1}\]  
where \(W^{\prime\prime}\) is the initial width of a brand-new cutting edge near the outer corner (mm), and \(W^{\prime}\) is the current width of a brand-new cutting edge near the outer corner (mm) (Figure 3). Figure 1: The provided description illustrates the FABA WP-01 drill from two different perspectives used in the experiments. From the left, a top view of the drill bit is depicted, showcasing its cutting edges and the general shape. Meanwhile, the image on the right offers a side perspective, emphasizing the length and contour of the drill bit. According to Equation (3), the state of the drill is divided into three distinct classifications:  
* \"Green\" tool wear class \(W<0.2\) mm. * \"Yellow\" tool wear class \(0.2\leq W<0.35\) mm. * \"Red\" tool wear class \(W\geq 0.35\) mm. Figure 1 illustrates the FABA WP-01 drill used in the experimental setup. The left part of the figure provides a top-down view of the drill bit, clearly showing the sharp cutting edges designed for efficient drilling into materials. This view emphasizes the precision and engineering behind the drill's design, crucial for achieving clean and accurate holes in melamine-faced chipboard. The right part of the figure offers a side view of the drill bit, showcasing its overall length and the angled cutting surfaces. This perspective highlights the drill bit's structure, which is designed to maintain stability and effectiveness during high-speed rotations and feed rates. Understanding both the top and side views of the drill bit helps in comprehensively analyzing its performance and wear characteristics during the drilling process. The figure above (Figure 4) illustrates examples of drilled holes categorized into three different classes, based on the condition of the drill and the quality of the holes. The first row shows holes classified as \"Green\", indicating that they were made with a new or minimally worn drill bit, resulting in clean and precise holes. The second row shows holes classified as \"Yellow\", which were made with a moderately worn drill bit, resulting in slightly less clean holes with some rough edges.