## 1 Introduction  
The technology of machining native wood and wood-based materials by multi-axis CNC machining centers is increasingly used especially in the manufacturing of complex parts, or so-called nesting milling. CNC machines are often used without direct control by a human operator and, therefore, the setting of appropriate technological parameters is extremely important for trouble-free machining, achieving the required quality of the workpiece, minimizing vibration and electricity consumption, and, last but not least, ensuring adequate work environment [1; 2]. The ongoing digital revolution (Industry 4.0) brings techniques for inspection and for collecting data on the production process and their online processing remotely using interconnected cyber-physical systems. It does not have to be only about evaluating data in real time, but also about their prediction with the aim of environmental protection and sustainability industry [3]. The problems related to this can result in the development of new intelligent sensors, methods, and procedures for measuring quantities that indirectly characterize the machining process (energy consumption, acoustic emissions, vibrations, dust) and are suitable for creating a digital twin of intelligent production [4]. Milling is a well-known manufacturing process, where many problems already have been addressed. Many studies were conducted to find dependence of roughness of machined material on cutting parameters. Generally, the surface roughness depends on spindle speed, feed rate, and tool diameter. To achieve a smoother surface, high spindle speed with slow federate should be used, ideally with a small diameter tool [5; 6; 7; 8; 9; 10; 11; 12; 13]. However, such parameters also create higher cutting forces which are undesirable [14]. A big aspect is from material itself. Especially where wood is concerned, material homogeneity plays a big role. Medium density fiberboard (MDF) is a wood-based industrial product. It is made from wood waste fibers bonded together by resin, while heated under pressure. MDF has certain advantages when compared to native wood and is currently preferred in many applications [10]. MDF roughness from manufacture increases with rising compression strength [15]. It is generally denser than particle board as well as plywood. Even though it consists of fibers and not veneers, it can be applied as a construction material in most cases, where plywood is used nowadays. The density of a typical MDF is between 500 kg\(\cdot\)m\({}^{-3}\) and 1000 kg\(\cdot\)m\({}^{-3}\) whereas the density of a particle board is in the range from 160 kg\(\cdot\)m\({}^{-3}\) to 450 kg\(\cdot\)m\({}^{-3}\). In contrast to natural wood, MDF does not contain knots or rings [16]. Experimental studies provided assessment of the concrete cutting parameters for machining isotropic and orthotropic wood-based materials [17; 18]. Vibrations during the machining process were subjected to multiple studies. Vibrations are often frequent problem which affects dimensional accuracy of the parts being machined, surface finish quality and tool life. Vibrations are induced due to machine faults, cutting tool, cutting parameters, workpiece deformation, etc. These vibrations are generally measured using accelerometers mounted on various machine parts elements [19]. From the point of view of vibration measurement, several articles were published, especially in the area of metal materials machining. A relation was found for steel [20] and titanium [21] machining, that surface roughness is most dependent on feed rate, while cutting speed has the highest effect on tool vibration. Similar results were found for aluminum in [22]. Other studies were focused on finding a relation between vibrations and surface finish, with signal spectrum analysis and wavelet packet transform (WPT), where it resulted in vibration ranges correlating the vibration amplitudes with resultant surface roughness.