طراحي و ساخت محور چهارم دوراني سيستم CNC جهت تحليل پارامترهاي پرداخت كاري چرخدنده مخروطي به روش MAF

چكيده انگليسي :

Design and Manufacturing of Rotary Axis for a CNC System to Analyze Finishing Parameters of Bevel Gear by MAF Method Mohammadreza Mardanizad m mardanizad@me iut ac ir Date of Submission 2012 04 29 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Dr Seyed Mohsen Safavi mosafavi@cc iut ac irAbstract In new designed workpieces surface roughness is a very important parameter which affects lifetimeand working quality of the parts Nowadays manufacturing of parts with very low surface roughness is akey purpose for most of advanced industries Sometimes it is impossible or very hard to achieve finesurface finish by conventional processes Surface finish accuracy and integrity of parts produced byconventional machining methods depends on machine tool system including machine tool cutting tool workpiece machining conditions and cutting fluid To achieve high surface roughness machine tool shouldbe rigid free from static form deviation and dynamic chatter or vibrations errors and also tool andworkpiece errors Furthermore with development of new hard to finish materials such as superalloys andceramics and composite materials variation of forces in machining process is natural and can not beavoided by changing of machine tool system Also materials such as ceramics and glasses are inherentlybrittle and failure of parts made of these materials is usually due to cracks created during machiningprocess Magnetic abrasive finishing MAF is one of the modern finishing methods which can be used toproduce nanometer range roughness on flat surfaces and also on inner and outer surfaces of cylindricalparts This method can also be used for some other geometries This process is suitable for working on hardmaterials such as ceramics and superalloys which are hard to be finished with conventional methods Bevel gears are included in a group of mechanical parts which are used widely in various industries Surface roughness of gear tooth is one of the important parameters affecting the lifetime of gear and itsnoise during working process In this study by adding of a rotary axis to a 3 axis miniature CNC mill asystem is designed and manufactured for finishing of spiral bevel gears This system can be used to studyand investigate the effects of some important factors of MAF process This system also can be used forfinishing of other types of gears straight bevel gears helical gears spur gears and also outer surface ofshafts Motion control of the axes of this system is done using a software called MACH3 and this reducesthe costs of system considerably After preparing the system design of experiments response surfacemethod is used to design appropriate experiments for studying of factors effects on ultimate surfaceroughness Then statistical analysis is done by MINITAB software on experimental data and importantfactors and their interactions are determined and finally a regression equation for estimation of surfaceroughness from process variables is obtained Analysis results showed that all of the studied factors i e rotational speed of magnetic tool current of electric coil and mesh number of abrasive particles have asignificant effect on ultimate surface roughness Among the studied factors current has maximum effectand rotational speed of the tool has minimum effect on reduction of surface roughness Experiments showedthat finishing of bevel gears by magnetic abrasive finishing process needs a long time so finishing of gearsby this method is not efficient in usual cases however it can be used in particular cases which require highsurface finish Keywords magnetic abrasive finishing surface roughness abrasive powder magneticfield design of experiments analysis of variance

مرداني زاد، محمدرضا

طراحي و ساخت محور چهارم دوراني سيستم CNC جهت تحليل پارامترهاي پرداخت كاري چرخدنده مخروطي به روش MAF

پرداخت كاري به كمك مواد ساينده مغناطيسي , زبري سطح , پودر ساينده , ميدان مغناطيسي , طراحي آزمايش , آناليز واريانس