RESUMEN
The formation of surface texture in milling is a complex process affected by numerous factors. This paper focuses on the surface roughness of X37CrMoV51 steel machined by shoulder milling. The aim of the study was to develop a mathematical model to predict the surface roughness parameter Ra. The proposed model for predicting the surface roughness parameter Ra in shoulder milling takes into account the feed per tooth, fz, the corner radius, rε, and the actual number of inserts involved in the material removal process as well as hmin and D(ξ). The correlation coefficient between the theoretical and experimental data was high (0.96). The milling tests were carried out on a three-axis vertical milling machine using a square shoulder face mill. The geometric analysis of the face mill shows that at a feed rate of 0.04 mm/tooth, cutting was performed by three out of five inserts, and when the feed rate exceeded 0.12 mm/tooth, material was removed by all inserts. The minimum chip thickness parameter and the standard deviation of the relative displacement increased as the feed increased. Over the whole range of feeds per tooth, the displacement increased by 0.63 µm. Higher cutting speeds resulted in lower minimum chip thicknesses and the average standard deviation of the relative displacements for the whole range of cutting speeds was 2 µm.
RESUMEN
Drilling with standard twist drill bits is the most common method to create cylindrical holes. With the constant development of additive manufacturing technologies and easier access to additive manufacturing equipment, it is now possible to design and fabricate solid tools suitable for various machining applications. Specially designed 3D printed drill bits seem more convenient for standard and nonstandard drilling operations than conventionally made tools. The study described in this article aimed to analyze the performance of a solid twist drill bit made from steel 1.2709 using direct metal laser melting (DMLM), which was compared with that of a drill bit manufactured conventionally. The experiments involved assessing the dimensional and geometric accuracy of the holes made by the two types of drill bits and comparing the forces and torques occurring during the drilling of holes in cast polyamide 6 (PA6).
RESUMEN
The article presents the results and process analysis of the face milling of aluminium alloy 2017A with the CoroMill 490 tool on an AVIA VMC 800 vertical milling centre. The study analysed the effects of the cutting speed, the feed rate, the actual number of teeth involved in the process, the minimum thickness of the cut layer (hmin), and the relative displacement in the tool-workpiece system D(ξ) on the surface roughness parameter Ra. To measure relative displacement, an original bench was used with an XL-80 laser interferometer. The analysis of relative displacement and surface roughness allowed these factors to be correlated with each other. The purpose of this article is to determine the stable operating ranges of the CoroMill 490-050Q22-08M milling head with respect to the value of the generated relative displacement w during the face-milling process and to determine its influence on surface roughness. The research methodology presented in this paper and the cutting tests carried out allowed the determination of the optimum operating parameters of the CoroMill 490-050Q22-08M tool during the face milling of aluminium alloy 2017A, which are vc 300 m/m and fz0.14 mm/tooth. Working with the defined cutting parameters allows all the cutting inserts in the tool body to be involved in shaping the geometrical structure of the surface, while maintaining a low vibration level D(ξ) > 1 µm, a low value of the parameter hmin > 1.5 µm, and the desired value of the parameter Ra > 0.2 µm
RESUMEN
This article considers the use of additive manufacturing to produce cutting tools for various machining operations, especially turning, milling, and drilling. The right geometry and material of the tool as well as coatings applied on cutting edges are crucial as they improve the life and performance of the tool. The study described here focused on a four-flute end mill made of maraging steel 1.2709 using a Concept Laser M2 Cusing Direct Metal Laser Melting (DMLM) machine. Before the printed tool was first used, it was examined to determine its dimensional and geometric accuracy, surface roughness, and surface structure. The measurement data showed that the tool required machining, e.g., grinding, to improve its geometry because the total runout of the shank and the cutting edge radius were too high, amounting to 120 µm and 217 µm, respectively. The cutting edges were sharpened to obtain a fully functional cutting tool ready to perform milling operations. The study aimed to check the dimensional and geometric accuracy of the 3D printed milling cutter and determine the optimal machining allowance for its finishing.
RESUMEN
The shaping process of surface texture is complicated and depends on many factors and phenomena accompanying them. This article presents the author's test stand for the measurement of relative displacements in a tool-workpiece system during longitudinal turning. The aim of this study was to determine the influence of edge radius on the relative displacement between the tool and workpiece. The cutting process was carried out with inserts with different edge radii for X37CrMoV5-1 steel. As a result of the research, vibration charts of the tool-workpiece system were obtained. In the range of feed 0.03-0.18 mm/rev, the values of the standard deviation of relative displacements in the x-axis were obtained in the range of 0.36-0.78 µm for the insert with an edge radius of rn = 48.8 µm. As a result of the work, it was determined that for the feed value of 0.12 mm/rev for all inserts, the relative displacements are the smallest. As the final effect, the formula for forecasting the Ra roughness parameter was presented.
RESUMEN
Micromachining, which is used for various industrial purposes, requires the depth of cut and feed to be expressed in micrometers. Appropriate stock allowance and cutting conditions need to be selected to ensure that excess material is removed in the form of chips. To calculate the allowance, it is essential to take into account the tool nose radius, as this cutting parameter affects the minimum chip thickness. Theoretical and numerical studies on the topic predominate over experimental ones. This article describes a method and a test setup for determining the minimum chip thickness during turning. The workpiece was ground before turning to prevent radial runout and easily identify the transition zone. Contact and non-contact profilometers were used to measure surface profiles. The main aim of this study was to determine the tool-workpiece interaction stages and the cutting conditions under which material was removed as chips. Additionally, it was necessary to analyze how the feed, cutting speed, and edge radius influenced the minimum chip thickness. This parameter was found to be dependent on the depth of cut and feed. Elastic and plastic deformation and ploughing were observed when the feed rate was lower than the cutting edge radius.