Papers by Keyword: Machining

Abstract: Cutting down on energy usage while keeping the material removal rate (MRR) as high as possible is widely acknowledged to be one of the most important goals in the machining industry for a considerable amount of time. So that we can create a forecast model for side-milling machining that makes the most efficient use of the feasible amount of power, the response surface method was utilized. After that, this model was used to establish which parameters should be optimized for the machining process. The response surface approach was applied to investigate the effect that several distinct cutting elements, factors like radial slicing depth, feeding rate, and spindle rpm, all examples (RSM), had on the total power needed throughout the cutting process. The data indicate that the variable known as the feeding rate is the most important factor in the amount of energy consumed. Reduced power consumption is an unavoidable natural byproduct of accelerating cycle durations and increasing feed rates. A radial how deep the wound is in 0.3 millimetres, a feed rate of 6,000 millimetres per inch, and a spindle speed of 12,000 revolutions per minute can produce a minimum power usage of 82.38 kilowatts, as the optimization model indicates. Keywords: Material removal rate, Machining, Power consumption

Abstract: The grinding processes of shaping materials are one of the oldest known. However, the first grinding machine tool did not appear until the beginning of the 19^th century. Industries as important as the automobile would not have been possible without its invention. One of the machine tools that made this development possible was the universal grinding machine patented by Joseph R. Brown in 1877. Unfortunately, none of these early machine tools have been preserved and only the patent remains. Therefore, in this work, a virtual model of this first universal grinding machine has been developed by applying reverse engineering techniques. For this purpose, the existing data in the patent and in some machine treatises of that time have been used. Based on this information, the functionality of each of its components have been interpreted and analyzed. Starting from a set of hypotheses, a scaled and parameterized functional 3D model has been developed. Additionally, a kinematic study of the grinding wheel drive system has been carried out. Hence, this digital model ensures the durability of an important piece of the universal industrial heritage. Furthermore, it can be used as a teaching tool for engineering students, showing the operation of a machine tool belonging to a historical context different from the current one, which does not differ substantially in its architecture of modern universal grinding machines.

Abstract: The continuous demand focused on optimizing titanium machining techniques in the aerospace industry, makes improving machining processes in this area of great interest to the industry. The contamination produced by the coolants used to machine titanium is a major problem to be addressed, since it is a material that requires cooling due to its strength, physical qualities and low thermal conductivity. That is why the implementation of a RHVT cooling system can improve the current situation. The aim of this work is to compare the final quality of the drilling by applying the system of RHTV (Ranque Hilsch Vortex Tube) cooling techniques and to see the advantages of its application with the dry machining process. This cooling system is expected to reduce drilling temperatures, thereby increasing the environmental performance of the manufacturing process. It is expected to set up a preliminary study based on a comparison between dry drilling and drilling assisted by the application of RHTV. Macro and microgeometric defects will be evaluated to determine the cooling system efficiency, as well as the machining temperatures reached.

Abstract: Abrasive waterjet cutting is a valuable method for removing material without causing thermal damage, making it suitable for machining materials of different thicknesses and minimising waste. However, machining thicker materials requires higher flow rates and pressure, resulting in increased energy consumption and surface defects that increase costs. This study proposes a multi-pass strategy to improve the performance of abrasive waterjet machining. The study aims to investigate the impact of the number of passes on the efficiency of machining a thick UNS A92024 alloy. Surface integrity will be evaluated from two perspectives: macrogeometry (such as machining depth and taper) using image processing, and microgeometry (surface roughness). The study will also analyse the relationship between the number of passes and traverse speed to identify the optimal combination and develop a predictive model to enhance overall process performance.

Abstract: The product quality of hard steel material formed by a shaping machine using HSS tools was studied under the influence of machining variables. The research focused on the effects of tool vibration on the surface roughness of the product. The experimental process was carried out by selecting the machining independent variables, namely: cutting speed (V) = 1 m/min; 2 m/min; 3 m/min; cutting thickness (a) = 1 mm, 1.5 mm, 2 mm; feeding motion (f) = 5 mm/step; 8mm/step; 10 mm/step. Shaping machine was operated with 3 fixed speed levels (n) of 21.8 rpm, 39 rpm and 59.8 rpm, respectively. The dependent variable, namely stroke per minute (n_p); and feed rate (V_f). The material used was ASTM A483-A high carbon steel. Vibration measurements were taken during machining using an ADXL 345 accelerometer and an Arduino Pro Mini with support for Arduino IDE 1.8.13 and USB TTL CP 2120 software. Vibration acceleration (a_f) on the tool was recorded and an evaluation was performed to determine the effects of machining variables on the final products. The results show that speed lavel of machine, feed rate , and cutting thickness majorly affect vibration. The lowest vibration was obtained at a speed (n) of 21.8 rpm, a feed rate (Vf) of 1 mm/s, and cutting thickness (a) of 0.2 mm. The highest vibration was obtained at n of 59.6 rpm, Vf = 1 mm/s and a of 0.4 mm. The quality of the product related to the surface roughness was mainly influenced by the machine speed levels. The roughness values ranged from 3.97 to 6.46 µm, with the lowest surface roughness or smoother surface achieved at a moderate speed of 39 rpm and higher surface roughness at high (59.8 rpm) and low (21.8 rpm) speeds.

Abstract: Carbon fiber reinforced polymer (CFRP) is commonly used in many industries such as sports equipment, aerospace and automotive industries because of its particular properties of low weight and high strength. When penetrating the plastic with a large amount of fiber, problems such as fiber pull-out, delamination and matrix smearing exist. Delamination is a major problem in drilling the components/parts and assembling composite materials. Cutting CFRP without cooling enhances cutting temperature, leading to an increase in delamination. This paper investigates the effect of the difference between with and without air cooling on the drilling of bidirectional CFRP laminates using carbide tools. The cutting parameters studied were cutting speed and feed rate, while tool wear was the response of this study.

Abstract: In this scientific study, the problem of automation of machine-building production is justified. A 3D model of the lathe is presented and its design is improved. Standard layout schemes based on the upgraded spindle assembly have been developed, which make it possible to increase the speed of this type of machine. The results obtained make it possible to achieve the desired cutting speed, which has significantly increased by 2-2,5 times. The constructed dependence of the deviation on the roundness of samples by the finite element method allows predicting the main indicators: feed rate, spindle speed, cutting depth, static imbalance, initial and final pressure. Also, the obtained analytical results allow us to establish the main regularities of forming the accuracy of this lathe.

Abstract: Additive Manufacturing of metal alloys offers unique advantages for producing net-shape components of complex geometries with very little waste of material. Nevertheless, machining operations may be needed on functional surfaces to get the required surface finish and geometrical tolerances. This poses challenging issues since the microstructural features characterizing the AM alloys are drastically different from those of the wrought alloys of the same chemical composition, which, in turn, may affect the mechanical and machining response to a great extent. This paper shows that both the machined surface integrity and tool wear are greatly affected by the microstructural features induced by the previous AM process as well as by the build-up orientation.

Abstract: Optimization procedures can be considered useful for machining applications. Most commonly, the optimization method is applied to search a trade-off between costs and profits, and it allows searching for the optimum cutting parameters to maximize the useful tool-life, minimize the time of production, etc. The selection of the optimal machining conditions which could maximize the process sustainability performance and the fatigue life of the machined product is the objective of the work presented. The numerical model developed is useful to have integrated results as input for the optimization algorithm in order to drastically reduce the number of experimental tests needed. In the present work, the optimization of the performance measures is carried out using a self-written Genetic Algorithm code implemented using the MATLAB software.

Abstract: Nowadays, the increased average age of patients and the decreased age at which arthroplasty is carried out represents a reason for the necessity of higher quality standards for prostheses. In particular, tribocorrosion generates an irreversible transformation of the materials and the release of particles and metal ions in toxic concentrations in the biological environment in which the systems are implanted. One of the most used materials for prosthetic implants is the Ti6Al4V alloy but its tribological behavior is still challenging for the application. Employing and optimizing severe plastic deformation processes represents a way to obtain prostheses with superior performance improving patients’ quality of life and reducing the burden on National Health Cares. Ti6Al4V bars have undergone machining with semi-finishing parameters and burnishing processes. Tribocorrosion tests have been performed in a custom-made cylinder-on-disk configuration employing Al2O3 counterparts and phosphate buffer solution with the addition of albumin as simulated body fluid. The effects of sole machining and its combination with burnishing on surface quality and specific wear rate (SWR) have been assessed with respect to as received surface conditions. Optical microscopy, stylus profilometry and sample weighing before tests and at specific intervals during the tests have been employed for characterization. As a main result, it has been found that burnishing process is able to improve SWR of Ti6Al4V samples with respect to both as received and machined samples. Furthermore, the overall behavior of tribological system is gradually improved first employing sole machining and then combining machining and burnishing, reducing SWR of counterparts as well.