سنگ زني كانتورهاي آزاد با استفاده از ژل ساينده مغناطيسي در قطعات فلزي و غير فلزي

چكيده انگليسي :

Free form Contour Finishing by Magnetic Abrasive Gel in Metallic and Non metallic Parts Mehdi Movahednia Email address m movahednia@me iut ac ir Date of Submission 20th February 2012 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Language Farsi Degree M Sc Supervisor s Name Seyed Mohsen safavi Associate Professor mosafavi@cc iut ac ir AbstractNowadays one of the new industrial requirements is high quality surfaces The high quality surface is onethat not only is without surface defects such as micro crack but has high precision dimension and also lowsurface roughness These mirror like surfaces are used in different industries such as semi conductiveproduction optic military and aviation Depending on the type of surface there are a lot of various ways tocreate mirror like surface One of the newer methods to create this kind of surface is magnetic abrasivefinishing MAF Magnetic abrasive finishing MAF is one of the advanced finishing processes whichproduces a high level of surface quality and is primarily controlled by a magnetic field In MAF theworkpiece is kept between the two poles of a magnet The working gap between the workpiece and themagnet is filled with magnetic abrasive particles A magnetic abrasive flexible brush MAFB is formed acting as a multipoint cutting tool due to the effect of the magnetic field in the working gap In the recentyears plenty of studies around the world are about MAF In this method finishing is done by using magneticforce on abrasive tool which is a kind of abrasive powder and squeezing it on work piece surface and alsomaking a relative motion between tool and work piece This method is a kind of grinding however becauseabrasive particles are flexible and removal rate is not so high it is categorized as super finishing or polishingprocess The process principle and the finishing characteristics of bonded and unbounded magnetic abrasivewithin cylindrical inner surface and free form contour are described in this study The unbounded magneticabrasive is a mechanical mixture of abrasive and ferromagnetic particles with a kind of lubricant Theloosely bounded powder is prepared for experimentation by homogeneous mixing of magnetic powder Fepowder of 100 mesh size abrasive powder SiC of 100 mesh size and lubricant called silicon oil Toinvestigate the effects of time rotation direction working gap and spindle speed on material removal change in surface finish and percent improvement in surface finish a series of experiments have beenconducted using several setups The surface roughness is measured by Mahr roughness measurer and alsoatomic force microscope AFM In this study aluminum cylindrical parts are used for internal surfacefinishing at first and the results studied The results shows 0 6 m Ra 1 3 surface roughness occurs in 15min following this experiment a study on free form surface as the main purpose of this project is started Due to the low efficiency of this step using of combinative methods and optimizing magnetic abrasivepowder combination is required Through this research effect of ultrasonic vibration assisted magneticabrasive finishing is studied and also a new method for magnetic abrasive powder making is presented Finally because of industry s wide demand for this process housing of vankel engine is polished using thismethod successfully The results demonstrated that surface roughness of this part with 60HRC hardness was reduced to 0 39mmRa from an initial value of 1 22mmRa within 60 min with high repeatability Key words Magnetic abrasive finishing Surface roughness Free form contour Permanent magnet Magnetic field

موحد نيا، مهدي

سنگ زني كانتورهاي آزاد با استفاده از ژل ساينده مغناطيسي در قطعات فلزي و غير فلزي

پرداختكاري سايشي مغناطيسي , صافي سطح , كانتورهاي آزاد , آهن ربايي دائمي , ميدان مغناطيسي