Kliknij ten link, aby zobaczyć inne rodzaje publikacji na ten temat: ABRASIVE FLOW MACHINING (AFM).
Rozprawy doktorskie na temat „ABRASIVE FLOW MACHINING (AFM)”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 25 najlepszych rozpraw doktorskich naukowych na temat „ABRASIVE FLOW MACHINING (AFM)”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj rozprawy doktorskie z różnych dziedzin i twórz odpowiednie bibliografie.
1
DHULL, SACHIN. "INVESTIGATION OF HYBRID ELECTROCHEMICAL AND MAGNETIC FIELD ASSISTED ABRASIVE FLOW FINISHING PROCESS". Thesis, DELHI TECHNOLOGICAL UNIVERSITY, 2021. http://dspace.dtu.ac.in:8080/jspui/handle/repository/18780.
Pełny tekst źródłaStreszczenie:
The current scenario of industrialization requires need for higher productivity which is met by
advanced material removal process, i.e., abrasive flow machining (AFM) in which the internal
surfaces of the workpiece is machined to higher accuracy level with the help of abrasive laden
media. In this paper, the conventional AFM setup has been made hybrid using electrolytic and
magnetic force arrangement alongwith rotational effect in order to achieve better results in terms
of material removal and surface roughness. The newly developed in-house polymer media were
utilized in the process and the input parameters taken during experimentation were magnetic flux,
electrolytic rod size and shape, rotational speed, polymer media, abrasive particles and extrusion
pressure. It was found that the material removal and surface roughness improvement were more in
electrochemo magneto rotational AFM process compared to conventional AFM process. The
experimental values were in confirmation with those obtained in the optimization techniques
applied, i.e., Taguchi L9 OA, Matlab fuzzy logic and GRA-PCA. In addition, the hybrid
mathematical model was developed and effect of different forces occurring in the process and
computational flow analysis of media have been explained. With advent of need for fast
productivity in terms of material removal and surface roughness of the workpiece, abrasive flow
machining (AFM) process is gaining rapid importance in the industries. In this process, the fine
finishing of the internal surfaces is done that are difficult to reach spaces using abrasive laden
polymer media. The media is extruded past the surface under high pressure with the help of two
sets of extrusion piston cylinder arrangements. Further various innovations done in the field of
abrasive flow machining have been studied in detail in a tabulated form. It included the
applications of the process and the different variant forms of AFM process. Hence it can be
concluded that this form of non conventional machining process is efficient both in terms of
surface roughness and material removal. The SBR media resulted in maximum material removal
during experimentation, i.e., 3.88 mg when input parameters, i.e., electrolytic voltage, number of
extrusion cycles and pressure were taken as 18 V, 4 and 10 bar respectively. The NR, NTR and
SR media had intermediate effect of material removal but minimum removal of material was
achieved in case of PBS media, i.e., 2.39 mg at 6 V voltage, 6 number of cycles and 30 bar
pressure. The material removal was first increased with higher rod size but afterwards its increase
was lesser. The surface plots obtained from RSM technique showed that MR obtained was 2.25
mg at 21 bar pressure and 7 number of cycles. As compared to conventional AFM setup, it was found that in EMR-AFM setup, 34.5 % and 17.8 % improvement in % Ra and material removal,
respectively, was obtained. It was found that MR was approximately 2.9 mg on an average when
machining was done on traditional AFM process, while it increased upto 4.5 mg in prepared
hybrid machine setup.
2
Howard, Mitchell James. "Development of a machine-tooling-process integrated approach for abrasive flow machining (AFM) of difficult-to-machine materials with application to oil and gas exploration componenets". Thesis, Brunel University, 2014. http://bura.brunel.ac.uk/handle/2438/9262.
Pełny tekst źródłaStreszczenie:
Abrasive flow machining (AFM) is a non-traditional manufacturing technology used to expose a substrate to pressurised multiphase slurry, comprised of superabrasive grit suspended in a viscous, typically polymeric carrier. Extended exposure to the slurry causes material removal, where the quantity of removal is subject to complex interactions within over 40 variables. Flow is contained within boundary walls, complex in form, causing physical phenomena to alter the behaviour of the media. In setting factors and levels prior to this research, engineers had two options; embark upon a wasteful, inefficient and poor-capability trial and error process or they could attempt to relate the findings they achieve in simple geometry to complex geometry through a series of transformations, providing information that could be applied over and over. By condensing process variables into appropriate study groups, it becomes possible to quantify output while manipulating only a handful of variables. Those that remain un-manipulated are integral to the factors identified. Through factorial and response surface methodology experiment designs, data is obtained and interrogated, before feeding into a simulated replica of a simple system. Correlation with physical phenomena is sought, to identify flow conditions that drive material removal location and magnitude. This correlation is then applied to complex geometry with relative success. It is found that prediction of viscosity through computational fluid dynamics can be used to estimate as much as 94% of the edge-rounding effect on final complex geometry. Surface finish prediction is lower (~75%), but provides significant relationship to warrant further investigation. Original contributions made in this doctoral thesis include; 1) A method of utilising computational fluid dynamics (CFD) to derive a suitable process model for the productive and reproducible control of the AFM process, including identification of core physical phenomena responsible for driving erosion, 2) Comprehensive understanding of effects of B4C-loaded polydimethylsiloxane variants used to process Ti6Al4V in the AFM process, including prediction equations containing numerically-verified second order interactions (factors for grit size, grain fraction and modifier concentration), 3) Equivalent understanding of machine factors providing energy input, studying velocity, temperature and quantity. Verified predictions are made from data collected in Ti6Al4V substrate material using response surface methodology, 4) Holistic method to translating process data in control-geometry to an arbitrary geometry for industrial gain, extending to a framework for collecting new data and integrating into current knowledge, and 5) Application of methodology using research-derived CFD, applied to complex geometry proven by measured process output. As a result of this project, four publications have been made to-date – two peer-reviewed journal papers and two peer-reviewed international conference papers. Further publications will be made from June 2014 onwards.
3
Henderson, Alistair. "Abrasive flow machining of nickel based alloys". Thesis, University of Nottingham, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.422738.
Pełny tekst źródła
4
Davies, Peter John. "The rheological and honing characteristics of polyborosiloxane/grit mixtures". Thesis, Sheffield Hallam University, 1993. http://shura.shu.ac.uk/3165/.
Pełny tekst źródłaStreszczenie:
Abrasive Flow Machining, (AFM), is a non-traditional machining process that is achieved by extruding polyborosiloxane, (a viscoelastic polymer), containing abrasive grit additions, across surfaces, edges, and through component cavities. The AFM process is a complex one and its machining mechanism is still only partially understood since previous research into the process has mainly been limited to qualitative study. The present work undertook to investigate the relationship between the rheological characteristics of polyborosiloxane/grit mixtures and the associated machining parameters. A significant increase in the quantitative data available with respect to both the rheological and machining characteristics of these mixtures has been provided as a consequence of the investigations. Experiments were conducted using low viscosity, (LV), medium viscosity, (MV), and high viscosity, (HV), polyborosiloxane base media, in conjunction with silicon carbide abrasive grit of 60 and 100 Mesh size; the ratios of grit to base polymer utilised in the experiments were 0,1, and 2. The test pieces used in the experimental work were mild steel dies having a diameter of 15mm and a length of 1 5mm, and the equipment used to conduct the experiments was an Extrude Hone mark 7A machine. The investigations conducted have revealed that for all polymer/grit mixtures an increase in the number of extrusion cycles results in an increase in the stock removed, an improvement in the surface roughness, and an increase in the temperature of the mixture. Furthermore as the usage of the medium increases the grit particle wear increases so that there is a corresponding decrease in the machining parameters. For all mixtures there appears to be no correlation between the viscosities of the base media types and the machining parameters. However, a relationship is demonstrated between the machining parameters and variations in the viscosities of the grit/polymer mixtures based on a specific polymer base. The factors that appear to influence this relationship are the grit to polymer ratio, the grit size, and the temperature. The most important of these parameters are suggested to be the grit to polymer ratio and temperature since these variables appear to affect the viscosity behaviour and the associated machining parameters. In addition the investigations showed that the viscosities and associated rheological dependent parameters correspond to the qualitative viscosity nomenclature given to the different media types by the manufacturer. A shear history effect is also exhibited in each of the polymer types.
5
James, Sagil. "Study of Vibration Assisted Nano Impact-Machining by Loose Abrasives (VANILA)". University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1427962995.
Pełny tekst źródła
6
Kurd, Michael Omar 1982. "The material and energy flow through the abrasive waterjet machining and recycling processes". Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/32766.
Pełny tekst źródłaStreszczenie:
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references (p. 109-111).
The purpose of this thesis was to investigate the material and energy flow through the abrasive waterjet machine and the WARD recycling machine. The goal was to track all of the material, water, abrasive, energy, air, and tooling through the different components of the machining and recycling processes. The material removal was found to be a function of length and part geometry, while all of the other variables were simply a function of time. The cutting speed determines the abrasive use, water use, and power use, and is varied based on the material, geometry, thickness and cut quality. The cutting speed was found to be linear with machineability--a measure of the material, almost linear with hardness--inversely related to thickness, somewhat inversely related to quality, and linear with power. Water was found to be the most abundant consumable, following by abrasive, together making up over 99% of the output waste. In the recycling process, roughly 60% of abrasive can be recycled after a single use, with the only significant consumable being power, used to dry the moist abrasive. Replacement tooling on both the abrasive waterjet and the WARD recycling unit were found to be negligible compared to the large amount of abrasive sludge produced every minute.
by Michael Omar Kurd.
S.B.
7
Jones, Andrew R. "Ultrasonic abrasive flow machining of closed dies : modelling of the dynamic pressure distribution within ultrasonically energised, polymer suspended abrasive and investigation of the polishing of closed dies". Thesis, University of Bradford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.694063.
Pełny tekst źródła
8
Gilmore, Rhys. "An Evaluation of Ultrasonic Shot Peening and Abrasive Flow Machining As Surface Finishing Processes for Selective Laser Melted 316L". DigitalCommons@CalPoly, 2018. https://digitalcommons.calpoly.edu/theses/1935.
Pełny tekst źródłaStreszczenie:
Additive Manufacturing, and specifically powder bed fusion processes, have advanced rapidly in recent years. Selective Laser Melting in particular has been adopted in a variety of industries from biomedical to aerospace because of its capability to produce complex components with numerous alloys, including stainless steels, nickel superalloys, and titanium alloys. Post-processing is required to treat or solve metallurgical issues such as porosity, residual stresses, and surface roughness. Because of the geometric complexity of SLM produced parts, the reduction of surface roughness with conventional processing has proven especially challenging. In this Thesis, two processes, abrasive flow machining and ultrasonic shot peening, are evaluated as surface finishing processes for selective laser melted 316L. Results of these experiments indicate that AFM can reliably polish as-built internal passages to 1 µm Ra or better but is unsuitable for passages with rapidly expanding or contracting cross-sections. AFM can also polish relatively small passages, but lattice components may prove too complex for effective processing. USP cannot achieve such low surface roughness, but it is a versatile process with multiple advantages. Exterior surfaces were consistently processed to 1.7 to 2.5 µm Ra. Interior surfaces experienced only partial processing and demonstrated high geometric dependence. USP significantly hardened the surface, but steel media hardened the surface better than ceramic media did. Both AFM and USP are recommended processes for the surface finishing of SLM manufactured parts. Good engineering judgement is necessary to determine when to use these processes and how to design for post-processing.
9
KUMAR, PRADEEP. "STUDY ON ABRASIVE FLOW MACHINING OF CAST IRON". Thesis, 2016. http://dspace.dtu.ac.in:8080/jspui/handle/repository/14445.
Pełny tekst źródłaStreszczenie:
In AFM process there is a mixture of abrasive particles and a polymer based carrier in a
typical proportion which is extruded under pressure through or across the surface to be
machined. The media acts as a flexible brush which is responsible for carrying out the
cutting action. AFM is very effective for internal and complicated surfaces. A number of
improved versions of AFM have been developed to enhance the material removal rate
during machining, to machine the intricate shape and for faster reduction of surface
roughness.
In the present study, a drill bit assisted AFM process is used. In this process a stationary
drill bit of a particular shape is held inside the work piece. Drill bit performs two
functions; firstly it increases the pressure of media and secondly it provides a particular
kind of flow. A particular kind of flow is the combination of three flows (straight
reciprocating motion, flute flow along the profile of the drill bit and scooping flow), selfdeformability
of the medium leading to intermixing of abrasives in the finishing region
and the presence of an additional force on the abrasives that result in more material
removal rate and high surface finish.
In the present investigation, three profiles of drill bit - a spline, two-start and three- start
helical profile have been used for experiments and to study the effect of these profiles on
various response parameters such as reduction of surface roughness and material removal
of workpiece (Cast Iron). L9 orthogonal array based on the Taguchi method has been
used to study the effect of the drill bit and other main AFM process parameters. The main
parameters are shape of the drill bit rod (H), number of cycles (n) and extrusion pressure
(p) that have been selected at three levels considering no interaction among them. All the
three process parameters have significant effect on the material removal rate and the
result shows type of drill bit has maximum contribution. For reduction of surface
roughness, the process parameters extrusion pressure and number of cycle are significant
with the latter having maximum contribution whereas type of drill bit has been found to
be insignificant. The experimental results show the maximum improvement in surface
finish is 28.12% on the inner cylindrical surface of the cast iron work piece with the
initial roughness 6.2 micron and the final value being 4.45 micron.
10
BHARDWAJ, ANANT. "COMPUTATIONAL AND EXPERIMENTAL ANALYSIS OF PARAMETERS IN CENTRIFUGAL FORCE ASSISTED ABRASIVE FLOW MACHINING PROCESS". Thesis, 2019. http://dspace.dtu.ac.in:8080/jspui/handle/repository/19746.
Pełny tekst źródłaStreszczenie:
Centrifugal force assisted abrasive Flow machining has played a vital role in improving the
efficiency of the traditional abrasive flow machining process. It has readily kept its stands
against the disadvantage of abrasive flow machining and has proven itself as an essential
alternative against AFM process. In this works three different rods of different shape
(rectangular, triangular and circular) are rotated in the centrifugal force assisted abrasive flow
machining setup and the amount of MR (material Removal) and the quality of the surface finish
have been observed. ANSYS 15.0 are used for the computational analysis of the centrifugal
force assisted AFM process. The three rods are separately modeled and are tested for the same
condition and found that pressure on the work piece which is a measure of the material removal
is more for the rectangular rod. In order to validate the simulation results, Taguachi
optimization technique was used in which the initial reading of material removal was taken by
measuring weight and the initial reading of surface Roughness was taken by Taylor Hobson
tally surf. After performing the experiment, it was found that for material removal the optimum
value would be 300 RPM of rectangular rod speed, extruded with 6 numbers of cycles. And
for the percentage improvement in surface finish the optimum values were 200 RPM of
triangular rod in which media is extruded to 9 numbers of cycles. Evidently it was found that
both the simulation and the experiment justify the centrifugal-force assisted AFM as the
suitable mode for finishing operation with the use of suggested Process parameters.
11
Pal, Ansuman Dutta. "Modelling of Abrasive Flow Machining". Thesis, 2015. http://ethesis.nitrkl.ac.in/7838/1/2015_BT_MOdelling_DUTTA_DAS.pdf.
Pełny tekst źródłaStreszczenie:
This report deals in an innovative modelling of abrasive flow machining process and simulation of the problem is done with CFD. High surface Finishing is achieved through Abrasive flow machining (AFM) process. In my project, a 2 D ANSYS assisted design is made to verify the axial and radial stress during the machining process. An already derived formulation for metal removal has been modified as per given conditions and assumptions to derive a new formula for the same. A new theoretical approach has been proposed in the current work with limitations of its own. Finally the model has been analyzed in ANSYS to compare with a previously done work, and the results verified that the current work is going in right direction. The MRR and surface removal were calculated for Titanium work piece with an industrial grade abrasive media with aluminum oxide as abrasive
12
KUMAR, VIKAS. "STUDY OF DIFFERENT TYPES OF ABRASIVE MEDIA USED IN ABRASIVE FLOW MACHINING". Thesis, 2015. http://dspace.dtu.ac.in:8080/jspui/handle/repository/16063.
Pełny tekst źródłaStreszczenie:
For products having internal inaccessible cavities or recesses, general finishing processes like lapping, honing etc. are used but they suffer from disadvantage of low quality of surface finish and that too with high equipment cost. Therefore need arises for an alternate process which has the capability of nano level finishing. Abrasive Flow machining (AFM) is such kind of fine finishing technique for these kind of products. This method has a unique property of simultaneous improvement in material removal and surface finish. It employs an abrasives laden semi-solid media, which acts as a selfdeforming cutting tool and can finish the complex cavities under a hydraulic pressure. The work piece hardness, no of cycle, volume of media, Extrusion pressure and properties of carrier media are the important process parameters that affect the performance of AFM. Abrasive flow Machining has a limitation of low material removal. So to reduce this limitation, a number of varieties of media have been used by many researchers and scholars of this field. So main aim in this report work is to study the different types of media used in this AFM process and to choose a polymer based media to cause more material removal and better surface smoothness. The five media used in this research work is Polyborosiloxane, Silicone Rubber, SBR Rubber, Nitrile Rubber and Natural Rubber, Out of which Silicone Rubber is best media.
13
Lin, Hsuan-Liang, i 林宣良. "Developing of abrasive flow machining with rotation motion". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/18851103715705965279.
Pełny tekst źródłaStreszczenie:
碩士健行科技大學
機械工程所
101
Abrasive flow machining (AFM) is a efficient method of surface polishing, In AFM process, two cylinders are used to control the up and down motions of the abrasive medium to polish workpiece surface. Moreover, it can quickly remove recasting layers which made by wire electrical discharge machining . However, conventional AFM method has difficulty achieving uniform roughness of an axial distribution in circular holes polishing since one-way motion of abrasive media. Therefore, a study with a novel helical passageway is one of the solutions to reduce the surface roughness. The helical motion of abrasive medium in the polishing area exerts an additional tangential force along the tangential direction of the workpiece excepting the original axial force and the radial force. The tangential component can affect the performance of radial and axial surface roughness and uniformity. However, this method may exist a disadvantage in increasing working time due to additional resistance on flowing velocity. In the present work, a rotational mechanism to drive cutting forces on the workpiece surface is developed by modifying AFM set-up. To perform multiple flowing paths of an abrasive medium, whose flowing character can enhance polishing precision by increasing the abrasive area and axial sheared forces. In this investigation, two main schemes both simulation and experiment method are developed. Above all, numerical results simulated by CFD-ACE+ software indicate that the motion of rotational passageway significantly affected multiple directions when the abrasive medium in the channels would produce multiple flowing paths of velocity. It predicted to obtain the goal for the even surface of an axial distribution in circular holes polishing. In addition, the one factorial experiment and Taguchi reaction characteristics method were adopted to verify the optimal combination of design parameters and factors of a rotational mechanism. The experiment results demonstrate the critical parameters, which include the rotation speed, the colloid concentration ratios, abrasive number. Finally, after conducted a series of experiments, the results indicate that the rotational passageway is superior to circular passageway, in reducing roughness improvement rate (RIR) by roughly 88% compared with RIR 61% for the circular passageway.
14
chiu, hsiao-hsuan, i 邱筱軒. "Application of spiral channels in abrasive flow machining". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/09449427274381964959.
Pełny tekst źródłaStreszczenie:
碩士清雲科技大學
機械工程研究所
95
Abrasive flow machining (AFM) is a simple and economical polishing method. However, it is difficult to reach the uniformity of surface roughnesses because of the processing mechanism that polishes the workpiece with axial movements. Therefore, several spiral cores with different shapes are put in the machine to form various channels, that changes the processing mechanism of AFM from simple axial reciprocations to axial and radial ones. The influence of diverse channels on surface roughnesses is investigated in this research. Flow fields and strain rate changes of media flowing in channels are obtained by CFD-RC simulation to gauge the improvement in surface roughness. Results show variances in surface roughnesses in axial direction of the workpiece with a deep circular hole. Furthermore, it can be meliorated much both uniformity and the improving rate by placing a spiral core in the workpiece.
15
Garanayak, Shakti Ranjan. "CFD analysis and Optimization of Abrasive Flow Machining". Thesis, 2013. http://ethesis.nitrkl.ac.in/4733/1/211ME2348.pdf.
Pełny tekst źródłaStreszczenie:
This study deals with a new approach to understand the micro finishing of abrasive flow machining process in which computational fluid dynamics is used to simulate the forces. Mathematical modelling is applied to model the micro finishing operation. The study is conducted to compare the simulated results with the existing experimental results. A flexible polishing tool comprising polishing medium is used to carry out the analysis. The relative motion between the polishing medium and the workpiece surface provides the required finishing action. In the present work a two dimensional computational fluid dynamics simulation inside the workpiece fixture is performed to evaluate the axial and radial stresses developed due to the flow of polishing medium. The present study also develops optimization for AFM process of Al. alloy using response surface method.
16
ALI, PARVESH. "INVESTIGATIONS OF HYBRID THERMAL ABRASIVE FLOW MACHINING PROCESS". Thesis, 2019. http://dspace.dtu.ac.in:8080/jspui/handle/repository/16943.
Pełny tekst źródłaStreszczenie:
Abrasive Flow Machining (AFM) is a nonconventional finishing technique used for the deburring and polishing of the surface and edges through the abrasive laden media. The sharp cutting edges of the abrasive particles abrade the material from the surface and remove the material in the form of micro chips. For the material removal mechanism in AFM process, abrasive particles impart a large amount of force and a lot of energy is lost due to friction between the surface and abrasive particles. This research discuss a new hybrid form of AFM process named as Thermal additive Centrifugal Abrasive Flow Machining (TACAFM), which utilizes the spark energy to melt the surface material and abrasive particles in the media easily removes the material with lesser amount of force and energy loss also minimizes. TACAFM process is a combination of Centrifugal force assisted Abrasive Flow Machining and Electrical Discharge Machining (EDM) process. This process utilizes the EDM mechanism for producing the spark between the rotating electrode and work piece surface. The electrode tip is designed in such a way that it maintains the gap between the electrode tip and the workpiece surface and also it allows the media to pass from one media cylinder to the other. The present work includes mathematical modelling of the developed Thermal additive Centrifugal Abrasive Flow Machining process for the calculation of force exerted by the abrasive particles on the workpiece surface and its material removal due to thermal effect. The mathematical model results were validated through the experimental observations. While finishing the work piece through TACAFM process, higher temperature is developed over the surface due to spark generation. This is important to analyze the temperature distribution over the surface. A simulation model is presented by using ANSYS® 15 software to analyze the effect of temperature around the workpiece surface on changing the gap between the electrode and workpiece surface with variable rotational speed of electrode. The simulation results describe the amount of gap and rotational speed of electrode to be taken for better surface properties. The present work also involves use of the Response surface methodology (RSM) to plan and conduct the experiments and determine the effect of input process variables such as current intensity, duty cycle, abrasive concentration, rotational speed of the electrode and extrusion pressure on material removal, percentage improvement in surface roughness, residual stress, scatter of surface roughness and micro-hardness of the workpiece surface. The finished surface of the components was characterized for the microstructure study using SEM and XRD analysis. The oxide layers and molten material on workpiece surface was also observed from SEM images. The experimental results of
xviii
TACAFM process showed average 44.34% improvement in material removal compared to conventional AFM process. The results also showed 18.78% error in mathematical modeling results in compared to the experimental results of TACAFM process. The optimum value of material removal and percentage improvement in surface finish was found as 36.571 mg and 42.38 % simultaneously at 12 ampere of current, 0.78 duty cycle, 250 rpm of rotational speed, 10 MPa of extrusion pressure and 0.3 abrasive concentration. The optimum value of residual stress, scatter of surface roughness, micro hardness was found as -151.921 MPa, 0.151 µm and 345.951 HV simultaneously. The 95% confidence interval of the predicted mean for the MR was 31.7542 < MR (mg)< 38.5195, for % improved Ra was 35.5311 < ∆ Ra < 43.0562, for residual stress -285.483 < Residual Stress < -301.458, for Scatter of surface roughness was 0.0921< SSR < 0.209 and for Micro Hardness was 291.367 < Micro Hardness < 350.17. The developed technique is confirmed to be a better process for achieving products having high level of surface integrity.
17
Dash, Rupalika. "Modeling and CFD Simulation of Abrasive Flow Machining Process". Thesis, 2015. http://ethesis.nitrkl.ac.in/7861/1/2015_MTR_RupalikaDas_613ME3007.pdf.
Pełny tekst źródłaStreszczenie:
The abrasive flow machining (AFM) is a new finishing operation that involves abrasive particles as the tool to remove work material. AFM is broadly known as “no-tool” precision finishing operation and the carrier media containing abrasive particles is called as “self-deformable stone”. In AFM, a semi-solid polymer-based media containing abrasive powders in a particular proportion is flown through the work-piece at a certain pressure. The AFM consists of three major components, i.e. machine, media and tooling or fixture. The machine consists of a frame structure, control system, hydraulic cylinder and the media cylinder. The extrusion pressure for a standard AFM process varies from 10 bars to 100-200 bars. The function of tooling and fixture is to position the work-piece and provide direction to the media flow through the work-piece. The media consists of a carrier, abrasive powder and some additives. The flow of the media can be modeled using finite volume method as it deals with flow of a fluid. In the present work, FLUID FLOW FLUENT available in ANSYS 15 software package was used for the modeling and simulation. A 2D model for a cylindrical work-piece and a 3D model for four rotary swaging dies along with the fixtures have been prepared. Validation has been done for the two models with the existing experimental data. The most affecting flow output parameters like dynamic pressure, velocity and strain rate for different volume fraction and media speed have been analysed. The 3D model was simulated for both the non-granular and granular flow. The effects of different abrasive particles for variable diameter and volume fraction on the flow output parameters like granular pressure and skin friction coefficient have been studied. The flow analysis of the outputs gives a prediction of material removal efficiency.
18
Pai, Hsuan-Hao, i 白軒豪. "Study of the surface wear in the abrasive flow machining". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/28863204693196096905.
Pełny tekst źródłaStreszczenie:
碩士清雲科技大學
機械工程研究所
95
Polymer gel mixed with the abrasive is used to polish the complex hole in abrasive flow machining (AFM). The flow behavior of this abrasive medium in the complex hole will directly affect the efficiency and the precision in AFM. For understanding the performance of the abrasive medium in AFM, a numerical software CFD-ACE+ is utilized to simulate the flow of the abrasive medium in the complex hole. And the experiment is used to verify the relationship between the surface roughness and the simulated result. A chain-hole model is established first by the drawing software in this study. And a non-Newtonian flow is applied to simulate the flow of abrasive medium in the complex hole by CFD-ACE+. Velocity, pressure and strain rate of the abrasive medium are the key point to find out the finished result in AFM. So these evaluated values are used to discuss the polished effect at different section in AFM. A mold steel (SKD-11) and brass are selected as the experimental materials, and utilized WEDM to cut a chain-hole in these materials. And these holes are polished by 50 wt% abrasive medium in AFM. Then use the simulated result to confirm the surface roughness change in the finishing process. The velocity of abrasive medium is low when this medium passes through the middle section of the complex hole. So it can produce a higher polish force in that section than the entrance and the exit. Besides, the abrasive medium has a large strain rate in the narrow cross section of the complex hole. It also makes a good finished effect in that section again. The mold steel roughness after AFM indeed has the similar consequence from the simulated results by CFD-ACE+. But the surface roughness of brass during AFM is not entirely coincided with the simulated results from CFD-ACE+.
19
Hsieh, Yu-Chi, i 謝育齊. "Study on the Effects of Helical Passageways in Abrasive Flow Machining". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/17756689594138493100.
Pełny tekst źródłaStreszczenie:
碩士清雲科技大學
機械工程所
99
Abrasive Flow Machining(AFM) is a efficient method of surface polishing, especially it can quickly remove recasting layers which made by wire electrical discharge machining (WEDM). However, AFM methods have difficulty achieving uniform roughness of an axial distribution in circular hole polishing due to limited unitary axial motion of abrasive media. Therefore, this study design a special mechanism of the helical flow passageway to perform multiple flowing paths of an abrasive medium, then the fluid produced in the polishing of multi-directional path to achieve the purposes of uniform polishing. For this investigation, we consider the comparisons both simulation and experiment method. Above all, CFD-ACE+ numerical software was used in the simulation of abrasive flow in the helical mold core to understand the behaviors of abrasive velocity distribution and shear strain rate changes. Analytical results indicate that the design of helical passageway will obviously produce multi-directional flowing path, and we can infer it effectively improve the axial uniformity of surface roughness by the deviation of shear strain rate changes. Finally, Experiment proceeding designed a variety consists of different type and different size of mold cores to verify the effectiveness of helical passageway in AFM polishing, such as the number of helical grooves, the gap between work-piece surface and helical edge, the thickness of helical slot and the number of turns. Based on the experiment results, it showed that the helical passageway is superior to circular passageway in reducing roughness improvement rate (RIR) by roughly 76% compared with RIR 61% for the circular passageway, which design conditions including for four helices groove, 0.5 mm gap, 0.5 mm thickness of helical slot and one helical turn.
20
Lin, Min-Han, i 林明翰. "Effect of Helical Passageway in the Polygon Hole Using Abrasive Flow Machining". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/99159093801635307437.
Pełny tekst źródłaStreszczenie:
碩士清雲科技大學
機械工程研究所
96
Abrasive flow machining (AFM) is a simple and efficiency polishing method. But it is difficult to get the uniform roughness in the polygon hole polishing, due to the axial movement of the abrasive medium in the working process. Therefore, helical cores with different shape are put in the hole to form various channels that change the mechanism of AFM form the simple axial motion to the multiple directions. Computational fluid dynamics (CFD) software was used here to simulate the motion of abrasive medium in the polygon holes. Velocity and strain rate of the abrasive medium in the channels were obtained by simulations to design the passageway that uniform roughness could be found. Simulation results shown that the abrasive medium would produce irregular variances by placing helical core in the polygon hole. That is to say the media have the motion with different directions. And in experimental results, the surface roughness could be uniformity when polygon hole close to circular.
21
SINGH, HIMMAT. "OPTIMIZATION OF PROCESS PARAMETERS USING CNT PARTICLE BASED ABRASIVE MEDIA USED FOR FINISHING OF BRASS WORKPIECE BY ABRASIVE FLOW MACHINING". Thesis, 2016. http://dspace.dtu.ac.in:8080/jspui/handle/repository/14939.
Pełny tekst źródłaStreszczenie:
Abrasive flow machining is a nontraditional finishing process and is used to polish metallic components, internal inaccessible cavities or recesses using a semi liquid paste. It was developed to deburr, polish, and radius surfaces having complex geometries and edges by flowing abrasives with a viscoelastic polymer (called as media) over them. Abrasion occurs wherever the medium passes through the highly restrictive passage. In this work, two way abrasive flow machining is used to optimize the material removal and % improvement in surface roughness on brass material. In this study three parameter are used level of carbon nano tube, level of pressure, number of cycle. The abrasive media is formed with the combination of polymer and gel, abrasive particle and carbon nano tube (CNT). Polymer is made with the help of some chemical like as silicon oil , boric acid and ferric chloride (FeCl3.6H2o) and ammonia carbonates (NH4CO3). This media is mixed with the level of CNT and experiment is conducted on brass work-piece.
Three process parameter level of CNT, Extrusion pressure and Number of cycle have been used for experiment to study the effect of these process parameter on % improvement in surface roughness and material removal of brass work-piece. L9 orthogonal array based on Taguchi method has been used to study the effect of various process parameter on selected on response parameter. All three parameter affects the material removal and surface finish, by using level of CNT material removal continuosly increased among other parameter while surface roughness is improved up to second level after decreases. In case of No of cycle from first level to second level material is decreased after that increased but for surface roughness improvement is little bit significant. Third parameter extrusion pressure have little bit significant on MR but highly significant for surface roughness improvement. Effect of CNT on material removal is continuosly increases. The percentage contribution of CNT is 14.98%.and the effect of other parameter on MR are percentage contribution of Extrusion pressure is 15.56% and the percentage contribution of Number of cycle is 21.22%. Optimum level is selected for material removal is C3 P1 N3. Effect of CNT on improvement on surface finish the percentage contribution of CNT is maximum is 23.84%.The percentage contribution of number of cycle is 23.14% and extrusion pressure which contribute 15.90%.
22
Chiu, I.-Kai, i 邱奕愷. "Study of the Polishing Effects on Polygonal Holes by Rotational Abrasive Flow Machining". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/jy8n89.
Pełny tekst źródłaStreszczenie:
碩士健行科技大學
機械工程系碩士班
106
Rotational abrasive flow machining (RAFM) is a reciprocating motion with an external rotating mechanism to polish the workpiece’s surface by using the mixed gels of silicon material and abrasive particles. Therefore, this flowing behaviour is proposed to perform multiple paths of abrasive media to enhance polishing uniformity by increasing the radial shear forces. In this research, the rotating mechanism is mainly divided into two parts. First, the timing belt pulley is very suitable for the transmission mechanism to drives the mold, because the driving control of timing pulley is more accurate without sliding. Next, the servo motor is adopted to drive timing pulley based on the higher precision to stable control the rotation velocity even with lower speed. In the process of exploring the efficiency of rotary fluid processing, it is divided into two stages. In the first stage, the motion behavior of the abrasive medium in the passageway is obtained through the simulation analysis. It is inferred that the surface roughness and the uniformity of the polished surface should be effectively improved from the multi-directional distribution of the motion path. Then, a series of RAFM experiments were utilized to find out the optimum conditions for different design parameters of a rotating mechanism, and machining parameters. Batch workpiece samples of SKD-11 steel through the heat treatment hardness to HRC 60˚ are cut out using the WEDM process. The experimental results showed that the optimal parameters including a #60 size of abrasive particles, the abrasive concentration of 1: 1 to polish the workpiece after 20 minutes, then use of diamond abrasive to finish the workpiece once again for 20 minutes, the surface roughness improvement rate can reach 81%. Finally, the contact angle between the water droplet and the tangent of the plane was compared to check the performance of surface hydrophobicity. The water droplets were dropped into the workpiece’s surface before RAFM polishing and after polishing. The angle results before RAFM polishing was 70 °, and the angle after polishing was 95 °. The surface hydrophobicity of the workpiece can be improved in RAFM process according to the results of experimental comparison.
23
Wen, Chih-Yuan, i 温智元. "Study of the Polishing Effects on Shaped Holes by Rotational Abrasive Flow Machining". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/3cgtjg.
Pełny tekst źródłaStreszczenie:
碩士健行科技大學
機械工程系碩士班
106
Due to the diversification of products, the application of the complex holes is widely existence in Industrial Products. The machining of complex holes product must to design an aided mold to manufacture, for example, using a punching die mold to make a star pattern or a brand pattern, etc. Most of the machining methods are processed by CNC milling machine, electric discharge machining and wire electric discharge machining. In the wire electric discharge machining process, a recast layer is produced to roughen the surface. There are existed many technologies to improve the surface roughness of workpiece. Abrasive Flow Machining (AFM) is one of the effective methods to remove the recast layer. The abrasive gel can polish without being limited by the shape. In addition, the combination of the timing pulley and the rotating mechanism in AFM system can increase the cutting force, and increase the material removal amount by rotating motion to obtain the higher precision of complex-hole’s surface. There are divided into two stages in the course of the investigation. The first part explored the effect of flow path design on the passageway through CFD simulation analysis. The second part is to find the optimum parameters through a series of experiments. The experimental factors include different pressures, abrasives, rotation speed, and abrasive concentration to explore the surface roughness and material removal of the complex holes. According to experimental results, the polycrystalline diamond powder has a better performance of surface roughness than the single crystal diamond powder due to the self-sharpening effect. Moreover, using the silicon carbide No. 60 as abrasive material can reduce the surface roughness from the original 0.67 μm Ra to 0.305 μm Ra, calculated the roughness improvement rate was 64.8%. Next, using diamond powder as secondary finishing material, the surface roughness was reduced to 0.265 μm Ra, and calculated the overall roughness improvement rate was 78%. The machining method indicated that it has obvious effects on the surface roughness improvement of the workpiece.
24
PANWAR, MANSI. "EXPERIMENTAL INVESTIGATION OF HELICAL ABRASIVE FLOW MACHINE SETUP FOR DIFFERENT TYPES OF WORKPIECE MATERIAL". Thesis, 2016. http://dspace.dtu.ac.in:8080/jspui/handle/repository/14771.
Pełny tekst źródłaStreszczenie:
Abrasive flow machining (AFM), also known as abrasive flow deburring or extrude honing, is an interior surface finishing process characterized by flowing an abrasive -laden fluid through a work piece. During the study different medias, workpieces and pressure ranges were chosen. These fluids are typically very viscous, having the different plasticizers. AFM smoothens and decreases surfaces roughness, and is specifically used to remove burrs; polish surfaces form radii, and even remove material. These experiments were conducted between aluminium, brass, mild steel at a range of 10, 15, 20Mpa. When an abrasive mixed with a polymer of special rheological properties and forced through a restricting medium, the abrasive and polymer will act as a self-forming tool that precisely removes work piece material and improve the surface finish at those areas restricting to the medium flow.
Different relationships between a number of sets of workpiece, media and pressure are obtained using TAGUCHI method and their analysis was performed over ANOVA technique. Styrene butadiene rubber which is the most common natural rubber has given improved outputs among other media. In the % improvement in the roughness came out to be 39.51% and 3.21mg for material removal analysis.
25
Chang, Tsang-Huai, i 張蒼懷. "Study of the Characteristic Effect of Elliptical Holes Polishing by Rotating Abrasive Flow Machining". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/28811666725888207114.
Pełny tekst źródła