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Abrassive Flow Machining

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Abrassive Flow Machining

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Abrassive Flow Machining

  1. 1. ABRASSIVE FLOW MACHINING PRESENTED BY Prateek jain(11375) Rahul bhagat(11374) Anand kumar(11370) Ashish somvanshi(11373) Piyush kumar(11377)
  2. 2. ABRASSIVE FLOW MACHINING  It is a process of polishing and smoothening internal surfaces.  The abrassive media is flown across the surface to be super finished either in a single direction or in 2 direction and is extrude through w.p,theirby finishing the w.p and smoothening the surfaces.
  3. 3. CLASSIFICATION OF AFM MACHINE  One-way AFM  Two-way AFM  Orbital AFM
  4. 4. ONE-WAY AFM  One-way flow AFM processing pushes abrasive media through the work piece in only one direction, allowing the media to exit freely from the part.
  5. 5. TWO-WAY AFM The typical two-way flow AFM process uses two vertically opposed cylinders to extrude an abrasive media back and forth through or around passages formed by the work piece and tooling . Abrasive action occurs wherever the media enters and passes through the most restrictive passages
  6. 6. ORBITAL AFM  Surface and edge finishing are achieved by rapid, low-amplitude, oscillations of the work piece relative to a self-forming elastic plastic abrasive polishing tool.  The tool is a pad or layer of abrasive-laden elastic plastic medium(similar to that used in two way abrasive flow finishing),but typically higher in viscosity and more in elastic.
  7. 7. PROPERTIES OF AFM  Deburring, radiusing, and polishing are performed simultaneously in a single operation  AFM can produce true round radii even on complex edges  Reduces surface roughness by 75 to90 % on cast and machined surfaces  AFM can process dozens of holes or multiple passages parts simultaneously with uniform results
  8. 8. APPLICATION OF AFM  Automotive  Aerospace  Medicine  Dies and Molds
  9. 9. AFM IN AEROSPACE INDUSTRY  Improved surface quality  Enhanced high cycle fatigue strength  Optimized combustion and hydraulics  Increased airflow  Extended component life
  10. 10. AFM IN AUTOMOTIVE INDUSTRY  Enhanced uniformity and surface quality of finished components  Increased engine performance  Increased flow velocity and volume  Improved fuel economy and reduced emissions  Extended work piece life by reducing wear and stress surfaces
  11. 11. AFM IN DIES AND MOLD INDUSTRY  Reduced production costs  Increased production throughput  Enhanced surface uniformity, finish and cleanliness  Improved die performance and extend life of dies and molds
  12. 12. AFM IN MEDICAL INDUSTRY  Eliminate the surface imperfections where dangerous contaminates can reside  Improved functionality, durability and reliability of medical components  Enhanced uniformity and cleanliness of surfaces  Extended component life
  13. 13.  International Journal of Emerging Technology and Advanced Engineering Website: www.ijetae.com (ISSN 2250-2459, Volume 3, Issue 2 ,February 2013) Jose Cherian, Dr. Jeoju M Issac Research Scholar, Karpagam University, Eachanari Post, Coimbatore- 641021 Professor, Department of Mechanical Engineering, MA College of Engineering Kothamangalam, Kerala, India.  Gov K, Eyercioglu O, Cakir MV. Hardness Effects on Abrasive Flow Machining. Journal of Mechanical Engineering. 2013; 59: 626- 31.  Eyercioglu O, CAKIR MV, GOV K. Influence of machining parameters on the surface integrity in small-hole electrical discharge machining. Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture. 2013. Reaserch Papers
  14. 14. RESEARCH PAPER 1 Effect of Process Variables in Abrasive Flow Machining • International Journal of Emerging Technology and Advanced Engineering • Website: www.ijetae.com (ISSN 2250-2459, Volume 3, Issue 2, February 2013) • Jose Cherian, Dr. Jeoju M Issac 1. Research Scholar, Karpagam University, Eachanari Post, Coimbatore-641021 2. Professor, Department of Mechanical Engineering, MA College of Engineering Kothamangalam, Kerala, India.
  15. 15. PROCESS MODELLING AND OPTIMIZATION  Williams and Rajurkar developed a stochastic model of AFM generated surfaces by Data Dependent systems (DDS) methodology.  Estimated the ratio of surface roughness peak height (RZ) to the centerline average surface roughness value (Ra) by DDS methodology and found to be between 1.4 and 2.2 micrometers for the AFM process.  A large wavelength corresponds to the main path of the abrasive while the small wavelength is associated with the cutting edges.  They proposed an expression for estimating the abrasive grain wear and the number of active grains(Cd). The estimated value of Cd can be used as a cutting life criterion for abrasives.  For small number of cycles, its value should remain fairly stable but with more and more processing, the abrasive particles may fracture and thereby increasing the Cd value. The downturn of Cd value indicates that the medium has been absorbed too much abrasives and needs replacement.  Carried out simulation of finished surface profiles and material removed considering the interaction of abrasive grain with work piece material.  Proposed a mathematical simulation model to determine the characteristics of the medium flow during finishing and its experimental verification.  They reported that a linear relationship exists between shear stress acting on the surface and the layer thickness of material removed.
  16. 16. EXPERIMENTAL RESULTS
  17. 17. Fig 2 Fig 3 Fig 4
  18. 18. FIG 8 , 9 AND 10
  19. 19. RESEARCH PAPER 2  This paper conducted on the finishing of difficult to machine materials like Ti6Al4V.  The influence of the AFM process on Ti6Al4V workpieces were investigated.  The results show that the white layer formed during WEDM is successfully removed by AFM in a few cycles for each workpiece.
  20. 20. ABOUT TI6AL4V  Ti6Al4V displays high strength, corrosion and heat resistant properties.  Are commonly used in high temperature applications such as turbine blades and rocket engines.  It is considered more difficult to finish using conventional techniques (grinding, lapping, etc.) than other metallic materials.
  21. 21. EXPERIMENTAL WORKS  The experiments were performed on Ti6Al4V.  The specimens were cut from the slabs by using wire electro discharge machine (WEDM) to 5x10x20 mm as shown in Fig.  The WEDM parameters kept constant for all specimens to ensure the pre-surface characteristics of the specimens.
  22. 22.  Table1 Surface roughness values of the specimens before AFM.  Table2 Physical, mechanical and thermal properties of Ti6Al4V.
  23. 23. THE ABRASIVE FLOW MACHINE  In this study a two-way AFM machine that has two vertically opposed chambers was used (shown in Fig.).
  24. 24.  The machine contains of a main frame, hydraulic unit, electronic control unit and heating-cooling unit.  The specifications of the machine are given in Table3.  The hydraulic unit ensures adequate movement and media pressure that can be automatically configured.  The control system is designed to control the volume of abrasive media and the number of cycles.  One cycle in two-way AFM process is composed of reciprocating motion of forward and backward of the piston ram in the media cylinder.  Thus cycle time depends on the piston speed and one cycle in the experimental study takes 2 minutes.
  25. 25. THE ABRASIVE MEDIA  The abrasive media that were prepared for the present study is a mixture of polymeric carrier, silicon carbide (SiC) abrasive particles, and 10% of hydraulic oil.  The specifications of the abrasive media are summarized in Table4  Before performing the experiments, the abrasive media is run for 3–5 cycles with a trial workpiece, so as to get uniform mixing.
  26. 26.  Preparing the abrasive media was the hardest process.  They have used Garnet,SiC, B4C and Al2O3 as a raw material of abrasive media.  They were washed by them as shown in Fig. and after that they were sieved to get optimum mesh size of this material.
  27. 27. EXPERIMENTAL PROCEDURE  The experiments were performed on the Ti6Al4V.  The workpiece holder (seeFig.) was used to hold the specimens allowing the flow of abrasive media through the WEDMed surfaces with an opening of 10x20 mm.  12 litres of abrasive media was flown through in each cycle.The experiments were carried out for 1,3,5,10,20,50 and 100 cycles.  The AFM pressure was 10 MPa and flow rate was 3 l/min.  The experiments were repeated for three specimens in each condition and the averages of the 5 surface roughness measurements were taken by using Mitutoyo SJ 401 surface measuring machine,with the cut off length 0.8 mm.  The specimens were cleaned by ethyl alcohol and weighed before and after the experiment by using SHIMADZU AUX220 balance.
  28. 28. RESULTS AND DISCUSSION Measurements of surface roughness  From the Fig.5 the surface roughness value decreased with increase in number of cycles for each specimens. The surface roughness (Ra)decreased significantly in the third cycle for Ti6Al4V specimens, the surface roughness after 20 cycles for Ti6Al4V are decreased slightly.
  29. 29. Material removal The Fig.6 shows that the material removal (MR) increases nonlinearly with the increase in the number of cycles. And the rate of MR decreasing with number of cycles. The reason for this slight decrease in material removal rate can be explained as the result of asperities on the workpiece surface before AFM. When the abrasive particles within the media machine the peaks, they become flatter than before and in the following cycles, the material removal is decreased.In the case of the Ti6Al4V workpiece total material removal is low.
  30. 30. SEM IMAGES  The EDMed surface is unlike that produced by any traditional machining process; it is characterized by globules and random debris of re-deposited and recast material. The high temperature changes the metallurgy of the material. The region affected by these thermal changes is referred to as the heat-affected zone (HAZ). The HAZ is included of a recast layer (white layer) of material that has been melted and re-solidified at the surface, white layer that is harder than the original material; contains micro cracks.  Microscopic photographs of the white layers for four groups of specimens are given inthe first cycles of the AFM process, the white layer is removed for specimens which were finished by B4C and SiC based media. From Fig.5 the improvement in the surface roughness values are similar and best improvement was occurred in specimens which were finished by B4C and SiC based media these results are well agreement to each other.  After removal of the white layer, abrasion behaviours of the four groups were changed. In the specimens (finished by B4C and SiC based media) has less smearing and ploughing. And no indentation of the abrasive particles to the surfaces was observed and the final surface roughness is better.  For Al2O3 based media finished specimen, the globules were fully removed from the surface in the fifth cycle but the lay of craters were fully removed after twentieth cycle and also have less ploughing. For specimen that were finished by Garnet based media, the globules were fully removed in the fifth cycle, but the debris was fully removed after fiftieth cycle.
  31. 31. SEM IMAGES OF SPECIMENS
  32. 32. WHITE LAYER  Fig. illustrates the removal of white layer with respect to the number of AFM cycles for DIN 1.2379 55 HRC specimens. The results of SEM images and the sectional microscopic views are in well agreement. The white layers were fully removed in the first cycle of B4C and SiC based media. In the case of Al2O3 and Garnet based media, five and twenty cycles were required to fully remove the white layers.
  33. 33. CONCLUSIONS From the experimental results, the following conclusions have been derived:  The white layer formed during WEDM is successfully removed by using all types of abrasives.  The results of SEM images and the sectional microscopic views are in well agreement. The white layers were fully removed in the first cycle of B4C and SiC based media. In the case of Al2O3 and Garnet based media, five and twenty cycles were required to fully remove the white layers.  Although the trends of surface roughness measurements are similar for all media groups, the results show that the media prepared by B4C and SiC has more surface improvement than Al2O3 and Garnet.  The surface improvement nearly the same for B4C and SiC therefore, SiC can be preferred due to its lower cost and better performance.  According to the desired finishing condition the Garnet can be used for its better cost.

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