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Air bearing 31120

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Air bearing 31120

  1. 1. A Seminar ON “AIR BEARING IN HIGH PRECISION SYSTEM” By Mr. KUMBHAR AKSHAY
  2. 2. CONTENT HISTORY INTRODUCTION WORKING APPLICATIONS ADVANTAGES /DISADVANTAGES CONCLUSION
  3. 3. HISTORY Air bearings are not a new technology In 1828 Rev. Wills published a work in the Cambridge Philosophical Society entitled “On the Pressure Produced on a Flat Surface When Opposed to Stream of Air Issuing from an Orifice in a Plane Surface”. In 1904 air bearings were patented by G Westinghouse in vertical steam turbine The technology was commercialized when IBM used air bearing spindles to produce large hard disc drives during the 70’s. Last decades brought high accuracy demands in production equipment applications.
  4. 4. •AIR BEARING •An air bearing is a non-contacting system where a gas film (typically air) acts as the lubricant and supports the two surfaces in relative motion. • As they are contact-free, air bearings avoid the traditional bearing-related problems of friction, wear, particulates, and lubricant handling.
  5. 5. •FRICTION Less Friction as compared to rolling And plain bearing • WEARIBILITY Materials used in other bearing eventually gets used up with time, which requires replacement. • LUBRICATION Unlike other bearing ,no lubrication is required. USE OF AIR BEARINGS
  6. 6. •STIFFNESS: A 6” diameter bearing running at 60psi actually has a stiffness greater than 2,000,000 lb/in with a load of 1,000 lbs •LOAD CAPACITY: •When compensation is used to increase bearing stiffness, the average pressure under the bearing is usually about 50 percent of the input supply pressure. Air bearings can therefore generally be considered to be 50 percent efficient with regard to input pressure.
  7. 7. Types of air bearing • There are basically two types of air bearing: 1)Aerostatic : a) Air Caster b) Porous Media c) Orifice 2)Aerodynamic: a) Foil bearing
  8. 8. Aerodynamic Bearing
  9. 9. Aerostatic Bearing
  10. 10. WORKING • Deflated : In the deflated stage, the air bearing , it is resting on the floor with most of the weight being supported by the center load pad. • Inflated : The second image shows the air bearing in an inflated form after it has formed a seal with the floor surface. At this stage, the load has not been engaged to float away from the floor.
  11. 11. WORKING • Load Lifted On Air : The above image shows the air bearing after it has engaged and floated the load. Compressed air will then start to escape from the bearing diaphragm into the area that is being contained by the floor seal. • The weight of the load causes the compressed air escaping out of the air bearing to force downward onto the floor surface thus causing the load to float away from the floor.
  12. 12. Applications in High Precise System •CMM •Automotive technology •Adjustment slider for optics production •Inspection Devices •Linear Drives •Medical Technology •Precision Machine Tools •Many more
  13. 13. CMM •A machine which takes readings in six degrees of freedom and displays these readings in mathematical form is known as a CMM. •It requires very high and precise readings •The probe which moves in X,Y, & Z direction is controlled by Air bearing.
  14. 14. Medical technology •Fat- and oil-free drives for respirators, stick-slip-free movements of scanners or a high rotary speed of large rotors have all been achieved with air bearings. •Air-guided computed tomography.
  15. 15. Linear drives Precision measurement stage High-accelerated Doppler drive Drive for production machine
  16. 16. Production technology •Air bearing for the adjustment of components: With air-guided units, optical components can be arranged to have the same diameter on a rotary table. •Adjustment slider for optics production: The linear slider, which is air-guided and statically determined, guarantees a high-precision positioning of the optical component before grinding
  17. 17. Testing Equipment •Many of the most accurate friction testing machines use air bearings to eliminate mechanical contact friction. •Being non-contact, air bearings are insensitive to high frequency short travel applications.
  18. 18. ADVANTAGES • GREATER PRECISION • HIGH SPEED • INCREASED TOOL LIFE • IMPROVED SURFACE FINISH • LONG BEARING LIFE • CLAENLINESS
  19. 19. DISADVANTAGE • HIGH GEOMETRY ACCURACY DURING MANUFACTURING. • CLEAN AND DRY SUPPLY OF PRESSURIZED AIR. • HIGH PRICING. • REQUIRE SOME KIND OF POWER CONSUMPTION
  20. 20. CONCLUSION •It is a technology that improves accuracy, resolution, smoothness and dynamic response performance over rolling element bearings • It is Viable clean solution for high speed applications. • These advantages turn them into a clean and environment Friendly bearing solution for various high-speed applications such as optical scanning equipment and machine tool spindles for PCB drilling and micro-milling.
  21. 21. References •Tobias Waumans, Jan Peirs, Farid Al-Bender, Dominiek Reynaert(2011) “Air bearing for high speed applications” Vienano •Crăcăoanu1 and F. Bremer(2008)” Air bearing in high precision system” •Manoj Kumar Sharma, Gohil Priyank(2013)” Study of Dynamic Characteristics and Design Analysis of Bush & Spindle of Ultra-Precision Aerostatic Bearing” IJSR •http://www.newwayairbearings.com/design/technical-resources/new-way-technical- reports/tech-report-1-air-bearing-comparison •https://en.wikipedia.org/wiki/Air_bearing •AIRFLOAT” How air bearings work” Decatur LLC · 2230

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