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Abrasive flow machining
- 1. Abrasive Flow Machining Mohit Ostwal Assistant Professor Department of Mechanical Engineering Jodhpur Institute of Engineering and Technology, Co-ed, Jodhpur 2/12/2016 MohitOstwal,Asst.Prof.,ME,JIET- Co-ed,Jodhpur 1
- 2. Content 1. What is AFM? 2. Need of AFM 3. Abrasive Material 4. Mechanism of AFM 5. Classification 1. One Way 2. Two Way 3. Orbital 6. Process input parameters 7. Application areas 2/12/2016 MohitOstwal,Asst.Prof.,ME,JIET- Co-ed,Jodhpur 2
- 3. Abrasive Flow Machining • It is basically used as a deburring process. • Developed in 1960 by Extrude Hone Cooperation. • AFM can • Polish and deburr parts internally • Polish through holes • Polish intersecting holes • Calibrate fuel injection nozzles to a specific flow rates • Uses abrasive grains mixed in a putty (a form of cement) like matrix which abrades the surface/burrs from the specific area of the material. 2/12/2016 MohitOstwal,Asst.Prof.,ME,JIET- Co-ed,Jodhpur 3
- 4. NEED • Smooth surfaces – Aerospace and precision components • High flow rates – Fluid dynamics and nozzles • Torque and fuel economy – Fuel nozzles and engine components • Eliminate the imperfections – Medical field 2/12/2016 MohitOstwal,Asst.Prof.,ME,JIET- Co-ed,Jodhpur 4
- 5. Abrasive Material • Abrasives • Aluminum oxide • Silicon carbide • Boron carbide • Diamond • Mixed in Polymeric medium • Viscoelastic polymer- shows change in viscosity when under pressure 2/12/2016 MohitOstwal,Asst.Prof.,ME,JIET- Co-ed,Jodhpur 5
- 6. Mechanism Of AFM 1. Initially the material is ploughed by the fine abrasives which come in contact with the work material as the rub over the metal surface with high pressure. 2. The material flow occurs in the direction of the motion of abrasive particles as well as in lateral direction, resulting into the formation of the leaps. 3. The further flow of abrasive particles causes continued work hardening which results in embattlement and fragmentation of the lips into micro chips. 2/12/2016 MohitOstwal,Asst.Prof.,ME,JIET- Co-ed,Jodhpur 6
- 8. Components of AFM • Machine • Tooling • Workpiece • Fixture plate • Fixtures • Pumping device • Abrasive materials/medium 2/12/2016 MohitOstwal,Asst.Prof.,ME,JIET- Co-ed,Jodhpur 8
- 9. Classification of AFM 1. One way 2. Two Way 3. Orbital 2/12/2016 MohitOstwal,Asst.Prof.,ME,JIET- Co-ed,Jodhpur 9
- 10. 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. 2/12/2016 MohitOstwal,Asst.Prof.,ME,JIET- Co-ed,Jodhpur 10
- 11. Advantages of One-way AFM • Faster cycle processing • Easy clean-up • Media temperature control generally not required • Able to process larger parts • Simpler tooling and part change-over • Accurately replicates air or liquids natural flow • Does not encapsulate work-part in media 2/12/2016 MohitOstwal,Asst.Prof.,ME,JIET- Co-ed,Jodhpur 11
- 12. Two-way AFM • Most widely used among the three. • 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 workpiece and tooling. Abrasive action occurs wherever the media enters and passes through the most restrictive passages 2/12/2016 MohitOstwal,Asst.Prof.,ME,JIET- Co-ed,Jodhpur 12
- 15. Advantages of Two-way AFM • Excellent process control • Can finish both ID and OD of component • Good control of radius generation • Fully automated system capabilities • Faster setup & quick-change tooling • Faster change-over of media 2/12/2016 MohitOstwal,Asst.Prof.,ME,JIET- Co-ed,Jodhpur 15
- 16. 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. 2/12/2016 MohitOstwal,Asst.Prof.,ME,JIET- Co-ed,Jodhpur 16
- 17. Orbital AFM(contd.) Before starting of finishing After starting of finishing 2/12/2016 MohitOstwal,Asst.Prof.,ME,JIET- Co-ed,Jodhpur 17
- 18. Machine Abrasive Workpiece Extrusion pressure Flow Volume Media flow speed Number of Cycles Medium viscosity Abrasive Concentration Abrasive type & size Restricting passage flow and area Ductile/Brittle 2/12/2016 MohitOstwal,Asst.Prof.,ME,JIET- Co-ed,Jodhpur 18
- 19. AFM process parameters Abrasive Based • Abrasive grain size used in AFM varies from 500 grit (tiny hole) to 8 grit (stock removal and stocking) • Large abrasives- cut faster • Small abrasives – better surface finish as well as they can reach narrow and complex surfaces easily. Machine Based • Pressure - 0.7 Mpa to 22 Mpa (100 psi to 3200 psi) 2/12/2016 MohitOstwal,Asst.Prof.,ME,JIET- Co-ed,Jodhpur 19
- 20. Capabilities of AFM process •Surface finish in the range of 28 to 280 μm. •Hole of 0.2 mm can be made. •Dimensional tolerances achievable upto ± 0.005mm. •Can reduce surface roughness by 75 to 90% on cast, machined or EDM sufaces. 2/12/2016 MohitOstwal,Asst.Prof.,ME,JIET- Co-ed,Jodhpur 20
- 21. Application 1. Aerospace industry • Improved surface quality • Enhanced cycle fatigue strength • Optimized combustion and hydraulics • Increased airflow • Extended component life 2/12/2016 MohitOstwal,Asst.Prof.,ME,JIET- Co-ed,Jodhpur 21
- 22. Application 2. 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 Grains in same direction will increase the flow rate 2/12/2016 MohitOstwal,Asst.Prof.,ME,JIET- Co-ed,Jodhpur 22
- 23. Application 3. 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 2/12/2016 MohitOstwal,Asst.Prof.,ME,JIET- Co-ed,Jodhpur 23
- 24. Application 4. Medical industry (Medical implants) • 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 2/12/2016 MohitOstwal,Asst.Prof.,ME,JIET- Co-ed,Jodhpur 24