بررسي پارامترهاي موثر ماشينكاري فتو شيميايي براي توليد چرخ دنده در ابعاد كوچك

چكيده انگليسي :

Investigated on Photochemical Machining Effective Parameters for Production Small Scale Gear Mohammad Reza Yarian Koupaei yarian@me iut ac ir Date of Submission 2010 4 25 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Alireza Fadaei Tehrani mcjaft@cc iut ac ir Abstract Photochemical machining PCM is a process of metal corrosion in which by using light and Photoresist desired areas are selected and machined in etchant Since 1950 by relying on the abilities of photochemical process vacuum tube in radio and television and other electronic devices were replaced with silicon semiconductors Thereafter photoetching was being used for production of television parts electronic chips disk encoders screens filters shaver machines and light sensitive sensors Photochemical machining method is being used as a suitable alternate for Punch Die Block and Fine blank especially when higher diversity more complex geometry and thinner specimens are desired during production process This replacement is of great importance regarding its effects on production time consumption and dimensional accuracy Among advantages of photochemical machining are the lack of mechanical and thermal residual stresses in the work piece being burr free after machining the lack of change of hardness and toughness of materials and higher dimensional precision Considering the above mentioned advantages of this method the wide range of various industrials such as horology military medical and optical industries is Regarding the need of gears in small scales diameter and thickness it is important to use modern methods of machining which produce minimum mechanical and thermal residual stress in the workpiece Photochemical machining is one of these processes that is under study in the present research Some effective parameters of PCM have been investigated in order to produce gears with thickness of 0 5mm external diameter of 9 mm and number of teeth 16 By using a template there would be some limitations such as the need for preparing the films with high accuracy and aligning it with workpiece resulting in more complexity and cost In this study the initial experiments have been done on the slide lam in order to preliminarily investigate the light exposure device and applied lenses microscope and lens as well as to find the effect of exposure time interval and centrifuge speed on the quality of gear teeth After preliminary tests the fact was concluded that it is better to use simple lens with less effective openings for reducing the energy intensity of light shone to photoresist Various types of acids such as HCl HNo3 H2O2 FeCl3 and Acid citric were studied inorder to suggest a suitable etchant for brass material removal these tests led to apply an etchant with the composition of come H2O HCl FeCl3 and H2O2 Mixture design was used to achieve the appropriate etchant based on DOE methods and the tooth thickness on the step circle was measured as the response Tests were carried out while other parameters such as exposure time and a Centrifuge speed were fixed In conclusion Obtained appropriate etchant was combination of 53g H2O 39g HCl 4 7g FeCl3 2g H2O2 Moreover Response surface design was applied to study the influence of exposure time rotation speed of spinner and duration of spinner rotation Data analysis showed that the square of exposure time and rotation speed would have a significant effect on tooth thickness on the step circle Subsequently the gears with 0 06 tolerance in tooth thickness on the step circle was produced through the tests Key words Photochemical Machining Spur gear Mixture design Response Surface Method

ياريان، محمدرضا

بررسي پارامترهاي موثر ماشينكاري فتو شيميايي براي توليد چرخ دنده در ابعاد كوچك

چرخ دنده ساده , اچنت , طراحي آزمايش