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Milling is a machining method used extensively nowadays in the manufacturing industry. In the milling process, one of the most important parameters affecting the machining performance is cutting tool geometry. In general, the effects of helix and rake angles, which are among the most important geometric parameters, on tool performance, are significant. In this study, the cutting force performance of wave form end mills that have a limited investigation both in the industry and academia is analyzed. The essential geometric factors in wave form end mills are designed with variable helix and rake angle along the helical cutting edges. In this work, the cutting force performance was experimentally and numerically compared with wave form tools, which are designed for reducing cutting forces and standard tools in terms of cutting forces on gray cast iron (GG25) according to ISO 8688-2 standard. The experimental results showed that an increase in the cutting force performance of wave form tools up to 11.4% compared to standard tools. Wave form tools with different geometric forms were compared with the validated finite element method (FEM) simulations based on experimental studies. As a result of FEM analysis, lower cutting forces (14.42%, 11.45%, 8.49%) obtained by 8–0.250, 6–0.450, 8–0.350 (wavelength-wave amplitude, mm) wave form tools compared to the standard tool. In addition, increment in cutting forces (− 6.37%, − 6.06%, − 5.92%) obtained by 8–0.150, 4–0.350, 8–0.650 tools. [ABSTRACT FROM AUTHOR]

In this study, the effects of drill geometry on cutting performance and hole quality in the drilling process were investigated. Two newly developed drill geometries were compared with two commercially available drill geometries. In the drilling tests on GGG50 cast iron, 4 different drills, 4 different cutting speeds and 4 different feed rates were used for L16 experimental design. The drilling tests were performed with and without cutting fluid. The results were evaluated using the axiomatic design method, one of the multi-criteria decision making methods, in terms of thrust force, surface roughness, deviation on hole diameter and length of adhering workpiece material around the chisel edges. From the obtained results, it was seen that the best results were obtained from one of the newly developed drill geometries. In addition, wear test was carried out without cutting fluid using the drill which performed best. With this best performed drill, after 100 drilling operations in wet and dry conditions and after 1500 drilling operations in dry conditions, SEM images were taken from the used drills. After drilling 100 holes both in dry and wet drilling conditions, there was almost no wear on the drills. However, some adhered workpiece material was seen on the drills. In addition, the amount of adhered workpiece significantly increased in dry drilling condition. [ABSTRACT FROM AUTHOR]

A significant part of today's chip removal processes are drilling holes. Many parameters such as cutting parameters, material, machine tool, and cutting tool, etc., in the hole-drilling process affect performance indicators such as surface roughness, tool wear, force, torque, energy consumption, and costs etc. While cutting parameters are easily planned by the operator during drilling, the selection and planning of the drill geometry are more difficult. In order to design and produce the new drill geometry, a wide time and engineering research are needed. In this study, the design and fabrication of new drill geometry were performed to improve the hole-drilling performance. The performance of the fabricated drills was judged with regard to surface roughness, thrust force, and drilling torque. In the performance tests, four different drill geometries, four different cutting speed levels, and four different feed rate levels were selected. Holes were drilled on AISI 4140 material. In addition, the optimization was performed in two phases. Firstly, the mono-optimization was carried by using Taguchi's S/N analysis in which each performance output was optimized separately. Secondly, the multi-objective optimization was employed by using Taguchi-based gray relational analysis (GRA). For the purpose of the study, two different drill geometries were designed and fabricated. Experimental results showed that the designed Geometry 4 is superior to other geometries (geometry 1, geometry 2, and geometry 3) in terms of thrust force and surface roughness. However, in terms of drilling torque, geometry 2 gives better results than other drill geometries. It was found that for all geometries, obtained surface roughness values are lower than the surface roughness values expected from a drilling operation and therefore surface qualities (between 1.2 and 2.4 μm) were satisfactory. [ABSTRACT FROM AUTHOR]

Reportedly, the drill geometry influences the drilling operation. In fact, the performance of the drill bit is strongly associated with productivity, thus with economy of production. Moreover, the typical performance indicators, i.e., deviation from diameter, cylindricity, perpendicularity, and concentricity, are altered by drill geometry. This fact stresses the need for a novel design of drills with further optimization of performance indicators of hole quality. In that perspective, herein, new drill geometries were designed and fabricated. Afterward, those drills were employed to create holes on AISI 4140 steel, and their performances were investigated and optimized to suggest cutting parameters of best interest. For performance tests, four different drill geometries, four different cutting speeds (90, 100, 110, 120 m/min), and four different feeds (0.15, 0.20, 0.25, 0.30 mm/rev) were practiced. To measure the performance of the drills, the quality of the drilled holes was studied in terms of the deviation from diameter, cylindricity, perpendicularity, and concentricity. During the experiment, geometry 3 that was developed as the original drill geometry exhibited poor chip evacuation. As such, geometry 4 was developed by considering these negativities, and it was found to demonstrate superior performance compared to other geometries in terms of hole quality. Furthermore, ANOVA revealed that the drill bit flute geometry is the most influential factor. Lastly, the Taguchi S/N approach disclosed that drilling with geometry 4 at the cutting speed of 90 m/min and feed rate of 0.15 mm/rev produced optimum machining performance. [ABSTRACT FROM AUTHOR]

Recently, the manufacturing sector is increasingly keen to apply sustainability at all levels of sustainability from system to products and processes. At the processes level, cutting fluids (CFs) are among the most unsustainable materials and need to be addressed properly in accordance with three main and decisive aspects, also known as the triple bottom line: ecology, society, and economics. Minimum quantity lubrication (MQL) is a promising technique that minimizes the use of CFs, thus improving sustainability. This paper presents a review of the literature available on the use of the MQL technique during different machining processes involving titanium alloys (Ti-6Al-4V). To carry out the study, four search engines were used to focus on the most cited articles published over a span of 17 years from 2000 to 2016. The performance and drawbacks are compiled for each eco-friendly technique: dry, MQL, and cryogenics with combinations of MQL and cryogenics, critically considering machining parameters such as cutting speed, feed rate, and output measures, namely surface roughness, tool life, and cutting temperature. After drawing conclusions from critical evaluation of research body, future research avenues in the field are proposed for the academics and industry. [ABSTRACT FROM AUTHOR]

In this study, the effects of cutting insert rake face forms and cutting parameters on the surface integrity in machining of AISI 316 L steel were investigated experimentally. The cutting forces occur during chip removal, surface roughness values on the machined surfaces with residual stresses on machined workpiece were measured, and metallurgical structure (microhardness and microstructural variations) of the surface layers formed as a result of machining were evaluated. The surface integrity was evaluated in terms of surface roughness, residual stress, microhardness, and microstructure analysis. In experiments, the best surface integrity results were obtained by cutting tools having QM form, and the worst surface integrity results were obtained by cutting tools having MR form. Under all these cutting conditions, it was observed that the surface integrity worsened when depth of cut and cutting feed were increased; however, the surface integrity improved when cutting speed was increased. In terms of cutting parameters, the best surface integrity was obtained with cutting speed 200 m/min, cutting feed 0.1 mm/rev, and depth of cut 1.25 mm; on the other hand, the worst surface integrity was obtained with cutting speed 125 m/min, cutting feed 0.3 mm/rev, and depth of cut 2.5 mm. [ABSTRACT FROM AUTHOR]

In this study, the surface roughness, dimensional accuracy, and circular and cylindrical deviations characterizing the hole quality were investigated experimentally. AISI 1050 steel in experiments was chosen as reference material due to its extensive applications in many areas. Uncoated and TiAlN coated by physical vapor deposition (PVD) method HSS twist drills with different diameters were used. Experiments were conducted on a CNC vertical machining center under dry condition with different cutting speeds and feed rates. The hole depth was 17 mm to ensure L < 3 D condition. After each experiment, hole properties such as surface roughness, dimensional accuracy, circular deviation, and axial misalignment between inlet and outlet holes (cylindrical deviation), all of those that show the hole quality, were measured, and the results were evaluated. In addition to experimental analysis, a statistical analysis was carried out to indicate the effects of drilling parameters on test results. Process parameters such as tool type, drill diameter, feed rate, and cutting speed were optimized with consideration of multiple performance characteristics using desirability functional analysis. As a result, coated tools compared with uncoated tools gave positive results for each evaluation criterion. As the most important parameter on surface roughness (Ra) was drill diameter, the most effective parameter on dimensional accuracy, and circular and cylindrical deviations was cutting speed for both uncoated and coated tools except from cylindrical deviation occurring in uncoated drill. [ABSTRACT FROM AUTHOR]