شبيه سازي سه بعدي اجزاي محدود فرايند ميكروفرزكاري آلياژ تيتانيوم

3D Finite element simulation of micro-milling process of titanium alloy

امروزه با ظهور سيستم هاي كامپيوتري پيشرفته تر، امكان شبيه سازي و مدل كردن مسايل بسيار پيچيده با دقت هاي بالاتر ميسر گرديده و از اين رو استفاده از شبيه سازي هاي نرم افزاري بعنوان روشي جايگزين بجاي آزمايش هاي فيزيكي در تحليل و بهينه سازي عملكرد فرايندها با رويكرد كاهش هزينه و زمان مصرفي، بيش از پيش مورد توجه قرار گرفته است. بكارگيري اين روش ها در مورد ميكروفرايندها كه مشكلات اندازه گيري هاي تجربي بعلت كاهش مقياس از ماكرو به ميكرو بيشتر مي شود، اهميت بسزايي يافته است. در اين تحقيق از يك مدل سه بعدي براي شبيه سازي فرايند ميكروفرزكاري در نرم افزار ديفرم استفاده شده است. اثر پارامترهاي برشي بر مشخصه هايي از فرايند نظير نيروي برش، دما و سايش ابزار مورد ارزيابي قرار گرفت. براي اعتبارسنجي مدل از نتايج نيرويي اندازه گيري شده به روش تجربي استفاده شد كه مطابقت بسيار زيادي بين نتايج شبيه سازي و تجربي مشاهده گرديد. نتايج نشان از قابليت بالاي مدل تهيه شده در پيش بيني رفتار فرايند داشته است.

complex problems with even higher accuracy. Regarding lower time and cost, the use of simulations instead of physical experiments is increasingly considered as an alternative method in the analysis and optimization of process performance. The importance of such methods becomes more significant when talking about micro-processes, since there are lots of difficulties in experimental measurements as a result of scaling problems by scaling down from macro to micro. In this study, a 3D model is developed using Deform-3D software for prediction of micromilling process behavior. Effects of cutting parameters on such characteristics as cutting forces, temperature distribution and tool wear are investigated. Johnson-Cook model is used to define physical and mechanical properties of the material in simulation. Two types of sticking and sliding friction contacts were assigned along the toolworkpiece contact length to have more realistic cutting condition. The two types of sticking and sliding friction contacts were employed to have more realistic contact model. Usui wear model is used to predict tool wear rate in the simulation. To check the validity of the model, force results of simulation are compared with the measured ones. A high level of correlation exists between the obtained simulation and measured results, which shows that the 3D developed model has good capability to predict process behavior.