## 1 Introduction  
Surface quality is a critical factor in the machining of hardwoods, directly influencing both the aesthetic characteristics and the functional performance of wooden components. In sectors such as furniture manufacturing and interior architecture, the demand for precise machining of wood and high surface quality has increased significantly. This growing need has led to the development and refinement of strategies that not only address the machining parameters but also need to consider the anatomical complexity and structural variability of hardwood species. Among the machining methods for face surfacing, conventional rotary cutter blocks are widely used for continuous, large-area planing. However, their size and geometry limit their effectiveness when small surface areas with alternating depths and contours are the milling requirement. These tools often cause significant anatomical alterations beneath the surface, including lateral distortion, tissue rupture, and fiber crushing, particularly in hardwoods, where variability in vessel distribution and fiber orientation generates uneven cutting resistance [1]. As a result, roughness produced under such conditions affects more than just surface appearance; it also undermines downstream processes such as bonding and coating. To address these limitations, more adaptable solutions have gained attention. Helical planning, for instance, is promoted for its ability to produce smoother surfaces and generate lower cutting forces but can also leave periodic ridges due to the geometry and motion of the tool path, especially at high feed speeds and for processing across the grain [2]. CNC-based face milling has become increasingly relevant in precision wood machining due to its capacity for controlled material removal and adaptability to complex surface geometries. Unlike traditional planning systems, face milling involves a perpendicular tool approach to the surface and is particularly well suited to CNC environments where tool paths can be finely programmed. Within this category, end mills with fronto-lateral cutting edges, tools that engage both axially and radially, have garnered interest for their versatility and geometric flexibility. Originally developed for metalworking and composite materials, such tools have been successfully adapted to the machining of solid wood components, where they enable high-precision processing of both planar and contoured surfaces [3,4]. Their geometry allows for an effective engagement with features such as recessed zones, narrow edges, and transitions in depth, making them particularly valuable in applications involving decorative or small-scale parts. Moreover, when properly selected and operated under optimized feed rates and cutting depths, fronto-lateral tools in face milling setups have been shown to deliver superior surface quality and reduced subsurface damage compared to conventional rotary cutter blocks [1,2]. Machining-induced subsurface deformation, such as cell compression and fiber rupture, can hinder adhesive penetration and reduce joint strength. These characteristics position face milling with fronto-lateral tools as a promising solution for fine woodworking applications that demand both dimensional accuracy and clean, bondable surfaces. Nonetheless, achieving optimal results requires close attention to the interplay between tool geometry, feed rate, cutting depth, and the anatomical structure of the wood. In a study on face milling of paper birch, [PERSON]. [2] employed a RotoPlane 16T face planer fitted with 34 insert knives to investigate the influence of the machining parameters on surface integrity. Three different feed speeds and cutting depths were tested, revealing that feed speed had a significant impact on both surface roughness and wettability, while cutting depth had a comparatively minor effect. These findings underscore the complexity of interactions between machining parameters and wood anatomical characteristics. Supporting this, [PERSON].