Generated Machining Method

The paper deals with the evaluation of material wear of injection moulds made of aluminium alloy Alumec 89 and copper alloy Moldmax HH in friction couples with plastomer materials with various filler contents. The friction relations in injection moulding were simulated in an adhesion dry wear test using an Amsler machine, with an area contact of the friction couple materials. The wear intensity was evaluated by determination of friction coefficient and relative wearing by the mass loss. Surface morphology changes of evaluated alloys after wear and the thermal conditions in particular friction couples were analysed simultaneously.

Virginia State University's manufacturing program is surrounded by the industrial/research communities including Rolls-Royce, Alstom, Newport News Ship Building, and Commonwealth Center for Advanced Manufacturing (CCAM) etc. Impellers, as advanced mechanical products commonly used in turbo-machineries, are heavily investigated by these companies on design, manufacturing and inspection. An impeller consists of numbers of similar blades revolving at 360 degrees onto a hub surface. The blade consists of a suction surface, a pressure surface, a leading edge, a trailing edge and a shroud surface. Each blade is ruled surface and twisted from the leading edge to the trailing edge. Due to the design complexity of impellers, 5-axis CNC machines are the most suitable for machining impellers because of the flexibility of tool orientations that is necessary to machine the area between the twisted blades. However, 5-axis CNC machines are too expensive for many universities or industries. 3-axis CNC machines are efficient on cutting time and cost, although serious collision will occur due to the tool movement that constraint only to translations movement. Thus, integrating 3-axis for rough machining and 5-axis for finish machining could be economic to fabricate impellers. Besides this, VSU recently received a generous NX PLM (Product Life Management) software gift from Siemens. Equipping our students with skills of "Digital Design Manufacturing and Process Monitoring of an Impeller Manufacturing" will better prepare them for job market or graduate schools. In this project, two groups of students were assigned different senior design tasks on design and manufacturing of impellers. Students in Group I design impellers using PLM's computer aided design (CAD) capability, then simulate the machining process and generate the NC code for impeller using PLM's computer aided manufacturing (CAM) capability, and then select cutting tools and cutting parameters, finally manufacturing the impeller with 3-axis and 5-axis CNC machines. Group II's task is to monitor cutting force, power consumption during the manufacturing process. Their tasks involve with sensor selection, Labview programming to integrate sensors, data collection and analysis on force and power on different machining features on impeller. Group II is also required to implement finite element analysis on the machining and fixture to simulate the strength and force response using PLM's computer aided engineering (CAE) capability. This paper details the challenges, solutions and outcomes of this senior project. The learning outcome from this project can improve several courses in manufacturing curriculum including: 1) CAD/CAM, 2) Manufacturing Processes, and 3) Manufacturing Automation etc.

In the modern manufacturing process metalworking fluid is an essential part of the cutting process. The application of coolant in between the tool and workpiece reduces the friction and carried out heat generated during the process. These cutting fluids are not only harmful to the workers and the environment but also increases the total cost of manufacturing. The cost associated with coolant handling and disposal is nearly 7% to 17% of the manufacturing cost. It is already proven that coolant is the main source of pollution in the manufacturing industries. But, Coolant plays an important role in lubrication, reducing friction and heat dissipation between the workpiece and the tool. Over the years, coolants are found a non-sustainable source in the manufacturing process. In the cryogenic machining process, the cryogenic liquid evaporates and becomes a part of the atmosphere which leaves zero residues. This characteristic makes cryogenic machining a sustainable solution for the industry. Thus, cryogenic machining can be an environmentally friendly alternative to the coolant. This paper is a review of cryogenic machining which will help in understanding the concept and mechanism of cooling in the cutting process.

The paper presents the entire process of designing and optimizing an injection mold for a polystyrene plastic anchor. The design process begins with a comprehensive market study of the polystyrene plastic anchors available on the Romanian market, and the results of this study are then used for the creation of a new model of anchor. After this first stage of design, the resulted model is optimized in terms of the injection process using the simulation software Autodesk Moldflow Adviser. After establishing the final form of the polystyrene plastic anchor, the mold is designed in Catia V5 using a series of standardized components. Manufacturing set-up is done in Catia V5 and Cimatron. In the end, the validation of the mold is performed using the injection machine Haitian Mars 2-2500.

The flow characteristics of the centrifugal fans with different blade outlet angles are basically discussed on steady and unsteady simulations for a rectangular casing fan. The blade outlet angles of the impellers are 35° and 25° respectively. The unsteady flow behavior in the passage of the impeller 35° is quite different from that in the steady flow behavior. The large flow separation occurs in the steady flow field and unsteady flow field of the impeller 35°, the flow distribution in the circumferential direction varies remarkably and the flow separation on the blade occurs only at the back region of the fan; but the steady flow behavior in the impeller 25° is almost consistent with the unsteady flow behavior, the flow distribution of the circumferential direction doesn't vary much and the flow separation on the blade hardly occurs. When the circumferential variation of the flow in the impeller is large, the steady flow simulation is not coincident to the unsteady flow simulation.

In order to ensure flexibility and rapid new product development, the mold industry made use of soft materials for cavity inserts in injection molds. However, materials of this kind are prone to wear. This article analyzes the topographic characterization of the surface and wear processes in injection molds cavities. Two materials have been used to produce the cavities: aluminum alloy EN AW-6082 T4 and copper alloy Cu Zn39 Pb3. The surface topography was measured with the use of optical interferometry profiling technology; roughness and surface parameters were determined according to ISO 4287, ISO 25178, and EUR 15178N. In order to complete this research, an experimental part with different thicknesses and shapes was designed, and cavity inserts of aluminum and copper were made. Polyamide PA6, with 30% fiberglass reinforcement, was employed in the experimental procedure. Measurements of cavity mold surfaces were performed after 9,200 cycles on each mold and at different locations on the mold. The surface measurement was made with a white light vertical scanning interferometry, also known as coherence scanning interferometry (ISO DIS 25178-604). The results are analyzed and differences between the two types of cavity inserts materials are discussed.

The main objective of this research is study the wear of a mould, made in easy machining material; aluminium EN AW-6082 T4 and the surface characterization of mould cavity, used in a polymeric manufacturing process, after several injection cycles. To evaluate the effectiveness of this materials in the plastic injection process, a test part with different thicknesses and shapes was designed and some inserts of aluminium were made. In the way of plastic material, a 30 % fiberglass reinforced polyamide PA6 has been employed in the experimental procedure. A reusable injection mould was used and surface measurements of mould cavity have been performed after 9200 cycles. The surface topography has been measured by using optical interferometry profiling technology and there have also been obtained roughness and surface parameters according to ISO 25178 and EUR15178N. In order to surface characterization, different areas of the mould cavity with different geometries, has been analysed. The ...

In order to ensure flexibility and rapid new product development, the mold industry made use of soft materials for cavity inserts in injection molds. However, materials of this kind are prone to wear. This article analyzes the topographic characterization of the surface and wear processes in injection molds cavities. Two materials have been used to produce the cavities: aluminum alloy EN AW-6082 T4 and copper alloy Cu Zn39 Pb3. The surface topography was measured with the use of optical interferometry profiling technology; roughness and surface parameters were determined according to ISO 4287, ISO 25178, and EUR 15178N. In order to complete this research, an experimental part with different thicknesses and shapes was designed, and cavity inserts of aluminum and copper were made. Polyamide PA6, with 30% fiberglass reinforcement, was employed in the experimental procedure. Measurements of cavity mold surfaces were performed after 9,200 cycles on each mold and at different locations on the mold. The surface measurement was made with a white light vertical scanning interferometry, also known as coherence scanning interferometry (ISO DIS 25178-604). The results are analyzed and differences between the two types of cavity inserts materials are discussed.

The paper presents the entire process of designing and optimizing an injection mold for a polystyrene plastic anchor. The design process begins with a comprehensive market study of the polystyrene plastic anchors available on the Romanian market, and the results of this study are then used for the creation of a new model of anchor. After this first stage of design, the resulted model is optimized in terms of the injection process using the simulation software Autodesk Moldflow Adviser. After establishing the final form of the polystyrene plastic anchor, the mold is designed in Catia V5 using a series of standardized components. Manufacturing set-up is done in Catia V5 and Cimatron. In the end, the validation of the mold is performed using the injection machine Haitian Mars 2-2500.

The design of mixed flow pump impeller blade is complicated,to refine the blade cross-section with design parameters to exert the maximum deflection is time consuming.In this optimization work of mixed flow pump impeller blade through artificial neural network(ANN) makes it easier to interpret the required thickness on the sample nodes of tetrahedral mess with respect to deflection of the blade which is obtained from ANSYS. ANN was used to optimize the thickness across the aero foil cross-section with respect to critical deflection.It was observed that the mixed flow pump impeller blade with inlet inclined blade position in the meridional annulus was more suitable as predicted by ANSYS and supported by ANN.

Despite the large number of abrasive waterjet machining (AWJM) models developed so far, there still has been confusion about the nature by which workpiece surfaces are eroded. The finite element method (FEM) could provide both qualitative and quantitative means in order to explain the AWJ erosion process. This paper presents an attempt to model the AWJM process using the powerful tool of the finite element method. The main objective is to develop an FE model which would enable to predict the depth of cut without any cutting experiments. The new model takes into account the precise representation of the constitutive behaviour of the workpiece material under AWJ dynamic loading conditions. Interaction of the abrasive particle with the workpiece material is traced at small time increments. The model accurately predicts the depth of cut as a result of AWJ impact and the results are in good agreement with experimental results.

A new methodology,for interactive design of turbomachinery blades ispresented. Software implementation,of the methods,provides a user interface that is intuitive to aero-designers while ,operating with stan- dardized geometric forms. The primary contribution is that blade sec- tions may ,be defined ,with respect to general ,surfaces of revolution which may ,be defined ,to represent the path of fluid flow through the

A concept of the formed suction intake design obtained with an algorithm for vertical axial-flow pumps is presented. The design methodology is a part of works conducted within project no. N N513 460240 supported by the Polish National Science Center. The proposed procedure is used to optimize intakes. The results of steady flow numerical computations in the suction intake as well as applications of the design optimization in the aspect of fulfilling two objective functions are discussed. The objective functions given by the authors concern the optimal inflow of the fluid into the impeller.

The complete optimization task for the case of the semi-open impeller with straight blades requires description of its geometry by means of, at least, eighteen design variables. In the case of constant meridional cross-section, required are at least eight design variables. Solution of the task with such a great vector of design variables requires much more time. One of the ways to obtain solutions with great variety of design variables is a comprehensive approach to the task including on the partition into minor subtasks. After decomposing the optimization task, one should choose a procedure for solving it. One of such procedures is parametric optimization, which is a two-stage minimization (maximization) method. This optimization is carried out in two levels. On the lower level, the multi-optimization of the decomposed parts of the tasks, depending on design variables, is being held. The solution of the lower level is used in the upper level (coordinating level) to find optimal coo...

A method for centrifugal compressor impeller's multi-objective design optimization was developed. The method was applied to a tested twelve radial bladed centrifugal compressor impeller, available in the open literature, as a test case characterized by three-dimensional viscous turbulent flow structure. The optimization target was to maximize the total-to-total adiabatic efficiency, and pressure ratio of the impeller at the design point, considering constant mass flow rate, rotational speed, and nearly constant torque. The aerodynamic analysis was performed using (CFX BladeGen) commercial software. This software solves the three-dimensional turbulent Navier-Stokes flow equations, with zero-equation turbulence model using finite volume method. The capabilities of the software were first validated by comparing the computed results with, an experimental data made by Mizuki [10, 11]. In this experimental work, yaw probes distributed along the impeller channel, were used to determine total and static pressures for hub and shroud. GAlib software was used to apply Genetic algorithm for handling of the optimization problem. The optimal impeller configuration, which corresponds to maximum efficiency, and maximum pressure ratio, keeping the same mass flow rate and rpm, was obtained with only 0.7% violation of the original torque value. A comparison between original and optimized impellers was made, which revealed the causes for efficiency and pressure ratio improvements.

Article history: Received 21 March 2019 Received in revised form 14 May 2019 Accepted 9 June 2019 Available online 3 July 2019 The primary disadvantage of dry ice blasting (dib) is high noise emission. The process may reach an alarming sound level of up to 130 dBA (safe noise exposure 85 dBA for eight working hours) at high blasting pressure. Present safety measures rely entirely on administrative control by encapsulating the entire system with sound insulation or using personal protective equipment. This limitation has made this research a significant work by controlling the noise with the engineering approach. Therefore, the research objective is to optimize dib nozzle geometry in term of divergent length on the effect of the noise level and to study the noise development characteristic inside nozzle geometry using CFD analysis. The research study employed a Computational Fluid Dynamic (CFD) method to evaluate the effect of different divergent length on the acoustic power level. T...

Fibre reinforced materials are getting more and more important for European manufactures. Coming from automotive and aviation industry nowadays also SMEs have to deal with these high tech materials. One of the biggest problem for such companies is the little experience they have in milling these materials. First cutting tests nearly ever result in very bad surface qualities and then companies often stop their efforts. The focus of the cornet project HPM was to overcome these hindrances for SMEs. The biggest problem therefore is the delamination of upper and lower layer during the cutting process. The Institute for Production Engineering developed a method to reach optimised surface qualities according to the application for different types of fibre reinforced materials like Aramid and Dyneema. Authors DI (FH) Dominik Berger; ao. Univ. Prof. DI Dr. Friedrich Bleicher; DI(FH) Christoph Dorn; DI Falko Puschitz, Vienna University of Technology, Institute for Production Engineering, Land...

The paper presents the entire process of designing and optimizing an injection mold for a polystyrene plastic anchor. The design process begins with a comprehensive market study of the polystyrene plastic anchors available on the Romanian market, and the results of this study are then used for the creation of a new model of anchor. After this first stage of design, the resulted model is optimized in terms of the injection process using the simulation software Autodesk Moldflow Adviser. After establishing the final form of the polystyrene plastic anchor, the mold is designed in Catia V5 using a series of standardized components. Manufacturing set-up is done in Catia V5 and Cimatron. In the end, the validation of the mold is performed using the injection machine Haitian Mars 2-2500.

The main objective of this research is study the wear of a mould, made in easy machining material; aluminium EN AW-6082 T4 and the surface characterization of mould cavity, used in a polymeric manufacturing process, after several injection cycles. To evaluate the effectiveness of this materials in the plastic injection process, a test part with different thicknesses and shapes was designed and some inserts of aluminium were made. In the way of plastic material, a 30 % fiberglass reinforced polyamide PA6 has been employed in the experimental procedure. A reusable injection mould was used and surface measurements of mould cavity have been performed after 9200 cycles. The surface topography has been measured by using optical interferometry profiling technology and there have also been obtained roughness and surface parameters according to ISO 25178 and EUR15178N. In order to surface characterization, different areas of the mould cavity with different geometries, has been analysed. The behaviour of wear rate has been analysed by the study of the evolution of the surface parameters and functional parameters in different points of the surface mould.

Artificial Neural Network (ANN) was used to predict the effects of splitter blades in a semi-open impeller on centrifugal pump performance. The characteristics of this impeller were compared with those of impellers without splitter blades. Experimental results for lengths of splitter blades in ratio of 1/3, 2/3, and 3/3 of the main blade length were evaluated by different ANN training algorithm. Training and test data were obtained from experimental studies. The best training algorithm and number of neurons were determined. The values of head, efficiency, and effective power were estimated in a semi-open impeller with splitter blades in ratio of 3/6 and 5/6 of the main blade length at the best efficiency point (b.e.p.). Here, as the splitter blade length increases; the flow rate and power increases, the efficiency decrease. All of the estimated values of performance in a semi-open impeller with splitter blades indicate the model works in line with expectations. Experimental studies to determine head, efficiency and effective power consumption in different types of pumps are complex, time consuming, and costly. It also requires specific measurement tools to obtain the characteristics values of pump. To overcome these difficulties, an ANN can be used for prediction of pump performance in semi open impeller.

Multistage centrifugal impellers with four different skew angles were investigated by using computational fluid dynamics. The purpose of this work is to investigate the influences of lean angle at the blade tip of the impeller inlet. Four variations of lean angles, that is, 8°, 10°, 15° and 20°, were made at first stage impeller. Reynolds Average Navier Stokes equation was used in simulation together with a shear−stress transport (SST) k-w turbulence model and mixing-plane approach, respectively. Three dimensional fluid flows were simplified using periodic model to reduce the computational cost and time required. A good performance was expected that the secondary flow can be effectively reduced in the flow passage of the impeller without excessive increase in manufacturing cost caused by the secondary flow. The results show that secondary flow affects the main flow intricately to form vortices or having non-uniform velocity in the flow passage, which in turn results in substantial fluid energy loss not only in the impeller but also in the guide vane downstream of impeller. The numerical solutions were performed and allowed the optimum design and operating conditions to be obtained.

In centrifugal pumps, the flow physics and dynamic performances are generally affected by any modification in blades shape and design layout. The investigations of estimating the optimum impeller geometry and the appropriate number of blades with a fitting angle need to find a better insight. At the present time, the dominant verification method used for investigation these characteristics are numerical simulation. Commercial code Fluent (CFD) under ANSYS software has been used for investigation the working characteristics of pump impeller under different conditions by using two different geometrical models. For these purposes, two different impellers with different blades number in 3D configuration are designed by using single arc curved blades design method and submitted for analysis and simulation to determine the best characteristics through comparison procedure. Conventional impeller case used as a base for comparison purposes during recording any changes associated with each individual case such as heads, flow rates and efficiency. The solution of dynamic analysis is carried out to approve that impeller structure can resist and withstand many variable loads and turbulent conditions. Results approved that, the static pressure, total head and efficiency are proportional with blades numbers and blades geometry. Even more, it is found that there are some important parameters have some effects on centrifugal pump performance such as inlet diameter of impeller and blades angle. It can be concluded from this works that suitable predicted results are estimated, and these analyzed results can used and adopted for this type of centrifugal pumps. 

Virginia State University’s manufacturing program is surrounded by the industrial/research communities including Rolls-Royce, Alstom, Newport News Ship Building, and Commonwealth Center for Advanced Manufacturing (CCAM) etc. Impellers, as advanced mechanical products commonly used in turbo-machineries, are heavily investigated by these companies on design, manufacturing and inspection. An impeller consists of numbers of similar blades revolving at 360 degrees onto a hub surface. The blade consists of a suction surface, a pressure surface, a leading edge, a trailing edge and a shroud surface. Each blade is ruled surface and twisted from the leading edge to the trailing edge. Due to the design complexity of impellers, 5-axis CNC machines are the most suitable for machining impellers because of the flexibility of tool orientations that is necessary to machine the area between the twisted blades. However, 5-axis CNC machines are too expensive for many universities or industries. 3-axis ...

A test rig has been built for determining a centrifugal compressor impeller flow field characteristic parameters. The compressor is working with a gas turbine engine of type 4M-1 (APU), which has a maximum speed of rotation of 27600 rpm. The engine shaft was being driven by a variable speed electric motor as a cold running test of the engine. The total and static pressures, and temperatures were measured at the impeller inlet, outlet, and in the collector, as well as the speed of rotation and mass flow rates. Whereas, the impeller efficiency, slip factor and aerodynamic blockage were calculated at every measured point. The mass flow rate has been varied by using a throttling gate, from its maximum to nearly surge point at each speed, where the surge symptoms start to appear. The mass flow rates and the speeds of rotation are corrected according to the standard ambient pressure and temperature. A loss model was developed using the basic fluid equations aided by some empirical relatio...

In this study, the shape of a mixed-flow pump impeller and its flow characteristics as a function of the specific speed are studied to improve its suction performance and efficiency. The shapes of mixed-flow pump impellers show a trend based on the specific speed. To construct the optimum database, a mixed-flow pump impeller with a specified specific speed is optimally designed using computational fluid dynamics (CFD) and design of experiment (DOE). The design variables of the impeller are defined in the meridional plane and vane plane development for impeller. By analyzing the trends of different mixed-flow pump impeller shapes, the optimized shape that satisfies the design specification can be designed easily. The trend exhibited by the design variables depending on the specific speed is analyzed using the shape of the optimally designed mixed-flow pump impeller. The shape of the mixed-flow pump impeller, as per the required design specification, is designed using the trends of the design variables based on the specific speed. The performance of the designed model is verified using CFD and experimental test.

In this work, an inverse design algorithm called Ball-Spine (BSA) is developed as a quasi-3D method and applied to the meridional plane of a centrifugal pump impeller in an effort to improve its performance. In this method, numerical analyses of viscous flow field in the passage between two blades are coupled with BSA to modify the corresponding hub and shroud geometries. Here, full 3D Navier-Stokes equations are solved within a thin plane of flow instead of solving inviscid, quasi-3D flow equations in the meridional plane. To demonstrate the validity of the present work, the performance of a centrifugal pump is first numerically investigated, and then compared against available experimental data. Defining a target pressure distribution on the hub and shroud surfaces of the flow passage, a new impeller geometry is then obtained in accordance with the modified pressure distribution. The results indicate a good rate of convergence and desirable stability of BSA in the design of rotating flow passages with incompressible, viscous flows. Overall, the proposed design method resulted in the following major improvements: an increase in static pressure along the streamline, 5% of increase in the pump total head and delay in the onset of flow cavitation inside the impeller.

To meet humans' need of enhancing the quality of life, the high-performance stand fan has become an essential appliance in every family. On the other hand, energy saving can not only solve the problem of environment protection, but also can reduce the cost of energy consumption. However, the aerodynamic performance and flow characteristics of the stand fan are rarely investigated and analyzed in a systematical manner. Therefore, this research intends to investigate the physical mechanism of the flow pattern and identify the design parameters of the stand fan by combining numerical and experimental methods. First of all, both the structure and performance of a commercial 14-inch stand fan are chosen for analysis and are set as the reference for the fan. The stand fan can be divided into the impeller and the protective cover. Clearly, the impeller blades have a great influence on the fan performance, so they are the first design target. In this work, CFD (computational fluid dynamics) software Fluent (version 14.5, ANSYS Inc., Canonsburg, PA, USA, 2012) is used to analyze and observe the corresponding influences on flow fields and aerodynamic performance by changing the design parameters such as the setting, twist, and inclination angles. Then, the protective cover is studied, improved and integrated with the designed impeller to further enhance the performance of the fan. The protective cover is modified by varying the spacing between the blade tip and cover, as well as varying the shape and angle of ribs to improve the fan's flow field and performance. Finally, the optimal fan mockup is made via CNC (computer numerical control) technology. Also, its acoustics and performance have been measured to validate the accuracy and reliability of the numerical simulation. The testing results show that the optimally designed stand fan is better than the reference fan with a significant 54% increase in max flow rate. In addition, it has more uniform velocity distribution compared with the reference fan to achieve a comfortable feeling for the human body. In summary, this research successfully establishes a reliable and systematic scheme to design the stand fan. Also, the corresponding performance influences caused by those important parameters are analyzed and summarized to serve as the design reference for the stand fan.

Cylindrical grinding is one of the important metal cutting processes used extensively in the finishing operations. Surface finish is the important output responses in the production with respect to quantity and quality respectively. The aim of this analysis was to study the effect of the cylindrical grinding parameters: work speed, feed and number of passes on surface roughness and material removal rate during the grinding of hardened OHNS material. The depth of cut and work speed was kept constant. The experiment was carried out on Schleif SA 5/2 U. OHNS is an important material mainly used for making wear resistant products such as dies, punches, measuring tools and spline gauges.

Micro-Electro-Mechanical Systems (MEMS) promises to revolutionize nearly every product category by bringing together silicon-based microelectronics with micromachining technology, making possible the realization of complete systems-on-a-chip. The process of making these micron length mechanical parts poses a challenge to understand and control the physical systems behavior on these scales. In this work, the vibrations of a 'micro-membrane' have been simulated for obtaining the natural frequency of the membrane. The vibrations are governed by an equation which is the solution of the partial differential wave equation. The membrane is considered to be fixed on all four sides. Simulations for different dimensions of the membrane are carried out and various plots are presented. Results for three different materials have been presented in this report. I.

Multistage centrifugal impellers with four different skew angles were investigated by using computational fluid dynamics. The purpose of this work is to investigate the influences of lean angle at the blade tip of the impeller inlet. Four variations of lean angles, that is, 8°, 10°, 15° and 20°, were made at first stage impeller. Reynolds Average Navier Stokes equation was used in simulation together with a shear−stress transport (SST) k-w turbulence model and mixing-plane approach, respectively. Three dimensional fluid flows were simplified using periodic model to reduce the computational cost and time required. A good performance was expected that the secondary flow can be effectively reduced in the flow passage of the impeller without excessive increase in manufacturing cost caused by the secondary flow. The results show that secondary flow affects the main flow intricately to form vortices or having non-uniform velocity in the flow passage, which in turn results in substantial fluid energy loss not only in the impeller but also in the guide vane downstream of impeller. The numerical solutions were performed and allowed the optimum design and operating conditions to be obtained.

Impeller blade geometry plays a dominant role on the velocity profile of the fluid flowing through the pump. Although blades' design is based on fluid dynamics considerations, it is sometimes limited by the available manufacturing methods, due to the required complexity in the geometry. In the present paper, the evolution of the velocity field in the blade passages of two anew designed radial pump impellers with different curvature and outlet blade angle is examined in order to verify their optimum design and characteristics. The numerical solution of the discrete three-dimensional, incompressible Navier-Stokes equations over a structured grid is accomplished with a commercial CFD finite-volume code. For each impeller, pressure and relative velocity distributions are presented and analyzed. The flow patterns in the blade passages are monitored and the mechanisms that dominate the flow field in the different regions of the impeller geometry are discussed. Furthermore, the new impellers that were tested numerically are manufactured in a CNC Milling Centre under the operation of sculptured surfaces; thus the feasibility of manufacturing the improved geometries is exhibited.

The complete optimization task for the case of the semi-open impeller with straight blades requires description of its geometry by means of, at least, eighteen design variables. In the case of constant meridional cross-section, required are at least eight design variables. Solution of the task with such a great vector of design variables requires much more time. One of the ways to obtain solutions with great variety of design variables is a comprehensive approach to the task including on the partition into minor subtasks. After decomposing the optimization task, one should choose a procedure for solving it. One of such procedures is parametric optimization, which is a twostage minimization (maximization) method. This optimization is carried out in two levels. On the lower level, the multi-optimization of the decomposed parts of the tasks, depending on design variables, is being held. The solution of the lower level is used in the upper level (coordinating level) to find optimal coordination variables. It has been shown that the result of multilevel optimization and the whole task optimization is the same in limits of accepted accuracy of calculation of the objective functions. Time of the calculation for the multilevel optimization task is over four times shorter than the time of the undecomposed task.

It has always been important to study the development and improvement of turbomachines' design, owing to their numerous uses and high energy consumption. Accordingly, optimizing turbomachine performance is crucial for sustainable development. The design of impellers significantly affects the performance of centrifugal compressors .

In centrifugal pumps, the flow physics and dynamic performances are generally affected by any modification in blades shape and design layout. The investigations of estimating the optimum impeller geometry and the appropriate number of blades with a fitting angle need to find a better insight. At the present time, the dominant verification method used for investigation these characteristics are numerical simulation. Commercial code Fluent (CFD) under ANSYS software has been used for investigation the working characteristics of pump impeller under different conditions by using two different geometrical models. For these purposes, two different impellers with different blades number in 3D configuration are designed by using single arc curved blades design method and submitted for analysis and simulation to determine the best characteristics through comparison procedure. Conventional impeller case used as a base for comparison purposes during recording any changes associated with each individual case such as heads, flow rates and efficiency. The solution of dynamic analysis is carried out to approve that impeller structure can resist and withstand many variable loads and turbulent conditions. Results approved that, the static pressure, total head and efficiency are proportional with blades numbers and blades geometry. Even more, it is found that there are some important parameters have some effects on centrifugal pump performance such as inlet diameter of impeller and blades angle. It can be concluded from this works that suitable predicted results are estimated, and these analyzed results can used and adopted for this type of centrifugal pumps. 

This article presents a procedure whose goal was to develop an effective methodology for deploying a 5-axis milling centre in industrial conditions. The method presented in the article, based on the manufacturing of the test piece, aims to reduce the time to deploy a new machine and minimize the effort put in by technological services and maintenance during tests and the process of deploying the machine tool in production. The test piece and its position have been designed in such a way that its manufacture forces the use of complex machine movements in the extreme area of the working space. The paper presents the results of tests involving the machining of a test piece on a CNC machine, measurement of the shape and dimensional characteristics of the object using CMM and analysis of machining accuracy in the context of the use of the machine in the production of aircraft transmission bodies. The material of the test piece is the same as the material of aircraft transmission housings, i.e. aluminum alloy. The universality of presented method is due to the fact that it is independent of the size of the machine's machining space, machine kinematics and also the special functions possessed by the machine; however, it gives a representation of their operation in the form of measuring sheets from the measuring laboratory.

3.1. CARACTERIZARE. CLASIFICARE. DOMENII DE FOLOSIRE Transmisiile prin curele sunt transmisii mecanice, care realizează transmiterea mişcării de rotaţie şi a sarcinii, de la o roată motoare la una sau mai multe roţi conduse, prin intermediul unui element flexibil, fără sfârşit, numit curea. Transmiterea mişcării se poate realiza cu alunecare (la transmisiile prin curele late sau trapezoidale) sau fără alunecare (la transmisiile prin curele dinţate). Transmiterea sarcinii se realizează prin intermediul frecării care ia naştere între suprafeţele în contact ale curelei şi roţilor de curea (în cazul transmisiilor cu alunecare) sau prin contactul direct dintre dinţii curelei şi cei ai roţii (în cazul transmisiilor fără alunecare). O transmisie prin curele se compune din roţile de curea-conducătoare 1 şi condusă 2-elementul de legătură (cureaua) 3 (fig.3.1), sistemul de întindere şi apărători de protecţie. Forţa necesară de apăsare a curelei pe roţile de curea se realizează la montaj, prin întinderea (deformarea elastică) curelei. Comparativ cu celelalte transmisii mecanice, transmisiile prin curele cu alunecare prezintă o serie de avantaje: se montează şi se întreţin u ş or; funcţionează fără zgomot; amortizează şocurile şi vibraţiile; necesită precizie de execuţie şi montaj relativ reduse; costurile de fabricaţie sunt reduse; transmit sarcina la distanţe relativ mari între arbori; permit antrenarea simultană a mai multor arbori; funcţionează la viteze mari; asigură protecţia împotriva suprasarcinilor. Dintre dezavantajele acestor transmisii se pot menţiona: capacitate de încărcare limitată; dimensiuni de gabarit mari, comparativ cu transmisiile prin roţi dinţate; forţe de pretensionare mari, care solicită arborii şi reazemele; raport de transmitere variabil, ca urmare a alunecării curelei pe roţi; sensibilitate mărită la căldură şi umiditate; durabilitate limitată; necesitatea utilizării unor dispozitive de întindere a curelei. Unele dintre dezavantajele transmisiilor cu alunecare sunt anulate de transmisiile prin curele dinţate. Astfel: mişcarea se transmite sincron, vitezele unghiulare ale roţilor fiind constante şi ridicate; randamentul mecanic este mai ridicat; pretensionare mai mică la montaj, deci o solicitare redusă a arborilor şi lagărelor. Principalele dezavantaje ale transmisiilor prin curele dinţate sunt legate atât de tehnologia de execuţie, mai pretenţioasă, atât a roţilor de curea dinţate cât şi a curelelor, cât şi de costurile montajului. Fig. 3.1 PDF created with pdfFactory Pro trial version www.pdffactory.com

In this paper, single-stage centrifugal fan is observed by numerical study on the flow characteristic. The objective of this paper is to study the flow characteristics in the centrifugal fan under variable inlet parameters by numerical analysis. Numerical study also focuses on the flow velocity, temperature and pressure distributions around the fan due to the effect of inlet radial tipped impeller by applying CFD software ANSYS CFX-15.0. The model of radial tipped centrifugal fan is created by Solid Works software. The flow simulation has been carried out the Reynolds Averaged Navier-Stokes equation for incompressible flow is solved with standard eddy-viscosity k-epsilon turbulence model to study the properties of the fan.

Este es un documento de Word se hace un informe con énfasis al conocimiento personal del aprendiz frente al manejo de Torno, par así facilitar al Instructor durante su espacio de formación y poder continuar con temas los cuales nosotros no tengamos conocimiento.

Abstract: This paper seeks to predict the performance of the side channel pump by considering
the influences of different wrapping angles. Firstly, three pump cases 1, 2 and 3 are modeled with
wrapping angles 15, 30 and 45, respectively. Secondly, different physical parameters comprising
exchanged mass flow, pressure and velocity distributions are plotted at the best efficiency point (QBEP)
to analyze the internal flow characteristics. Since the flow exchange times depend on the size of the
wrapping angle, the size of the wrapping angle has significant effects on the pump head performance.
Case 1 with the smallest wrapping angle recorded the largest head improvement at all operating
conditions compared to case 2 and case 3. Case 1 at QBEP attained a head coefficient increase of about
9.8% and 38.6% compared to that of case 2 and case 3, respectively. However, the size of the wrapping
angle had a slight effect on the pump efficiency; thus, case 1 still predicted a marginal increase in
efficiency compared to case 2 and case 3 at all operating conditions. Lastly, the numerical simulations
were validated with experimental data after manufacturing pump case 2.

An impeller design for a respirator is addressed in several textbooks and research articles. According to practiced methods, the overall dimensions and properties of an impeller can be determined using computational fluid dynamics (CFD) and thermodynamic relations. Designing impeller for a respirator is important for fluid flow analysis. The impeller meridional profile is an important detail as a significant influence on the performance. Four, Six blade impellers are commonly used in the industries presently. In this study; I have proposed 20 blade impeller, in order to increase the outlet flow velocity and cutting down the cost. Also, Comparison between these impellers is made in respect of other aspects like material, outlet velocity, fluid discharge, and efficiency. The material used for 4, 6 blade impellers is steel and the material used for 20 blade impeller is Acrylonitrile butadiene styrene (ABS) which is used to reduce noise and cutting down the cost of the impeller.

Special designed polishing devices for the correction of dual surface optical flats for interferometry and laser optics use correcting rings to control the active surface of the tool. The article outlines the dynamic of these rings, rotated by the friction between them and the main tool, and its consequences.