## 1 Introduction
[24] examined the effect of adding hBN nanoparticles to nanofluid-minimum spoilage on tool life, tool-wear patterns, temperature, and roughness in turning Inconel 625. As a result of their studies, they stated that 0.5% vol. hBN nanofluid gives good values for low roughness and tool wear and extended tool life. [PERSON] and [PERSON] [25] conducted an experimental study on chip morphology and cutting tool life in hot machining of Monel-400 material. They carried out their studies according to different processing parameters and heating temperatures. [PERSON] et al. [26] carried out a study on the useful tool-life estimation of worn tools with different machining parameters. For the prediction, they developed a proportional hazards model based on Weibull. As a result of their studies, they compared the accuracy of the developed model with the experimental data and stated that it was safe. [PERSON] et al. [27] studied the drilling of Inconel 718 alloy according to a sustainable manufacturing process to determine the potential for cryogenic machining. They determined that cryogenic machining increased tool life up to 87.50%. As can be understood from this summarized literature review, various options were applied to elongate the tool life in machining operations. This paper proposes a new model for obtaining longer tool life, which is separated from the counterparts as it addresses an easy, effective, and cost-friendly approach. The development of tools with a specific design using a continuous edge opens the possibility for using a new very effective way of increasing tool life. This method is based on the selective exchange of the worn cutting edge (SEWCE). This method was developed at the Bydgoszcz University of Science and Technology for tools with a continuous cutting edge--without a nose [28,29]. The principle of the SEWCE method is to replace a worn edge by moving it to remove a fragment of the edge that determines the roughness of the machined surface. Oblique cutting with a straight cutting edge is researched both with positive and negative edge inclination angles [29,30]. The SEWCE method was first used for longitudinal oblique turning with a single straight edge (\(\lambda_{\text{s}}=-60^{\circ}\)) [28]. In the trial, the wear criterion was VB = 0.2 mm because of the inclination angle and corresponding sliding distance of 0.3 mm. The worn cutting edge was moved in the specified displacement, such as 'dl' of the active part of the cutting edge 'l'. Elongations of dl = (1.0, 0.5, 0.33, and 0.2) were assumed. The results show the possibility for a very significant increase in tool life, especially for dl = 0.2. Tool life for cutting using the SEWCE effect was similar to tool life obtained for the new cutting edge. Using a straight cutting edge, a positive flat angle \(\alpha_{\text{f}}\) was obtained when the edge was displaced, which promotes its reuse. A virtual model of the special tool for oblique cutting using a straight cutting edge with a special mechanism for moving the cutting insert was represented. The concept of using SEWCE for a circle handle insert was presented in [28]. The paper shows both theories of the SEWCE concept, which uses a circle insert in orthogonal cutting, and the experiment results. [PERSON] et al. [28] identify the edge fragment shaping the surface roughness according to the geometric and kinematic mapping of the edge (GKME) as the smallest renewal movement of the edge, and the hatch of the entire contact ensures complete edge replacement. However, the presented test results indicate that a higher edge rotation is necessary. The authors explain this by the influence of additional cutting-edge wear phenomena mainly related to the hardening of the machined surface [3]. The results indicate that it is advisable to conduct further research into the wear process of a continuous edge, and to search for new applications of the presented SEWCE effect for a significant increase in tool life and reduction in its cost.