Havacılık endüstrisinde kullanılan alüminyum alaşımlarının karbür parmak frezeler ile işlenmesinde takım ömrü analizi

In today?s competitive aerospace and a ircraft industries, demand in manufacturing products with high speed, high precision and lower cost is increasing. According to the Airbus reports, number of commertial aircrafts is doubled every 15 years. Milling is one of the major manufacturing processes in producing aerospace and aircraft parts such as all structural parts and jet engine components. In aerospace and aircraft industry, removing of 90-95% of the bulk material with milling is very common to lower the weight of parts. Therefore, milling is perhaps the most critical manufacturing process in these critical parts. Selections of optimal machining conditions and the appropriate tools based on scientific analysis are very critical for high quality part manufacturing with lower cost in shorter cycle times. When machining velocities are increased in order to reduce the process time, machining forces, heat generated and process temperatures all increase. The harsh machining environment accelerates the tool wear. As a result, worn tools generates higher forces and more deformations on parts and tools, may cause bad surface quality and scraped parts, and sometimes may results into catastrophic failures. Along with negative effects on the work safety, machining center and final product, the tool costs are one of the main contributors of the overall cost. Therefore, accurate prediction and optimization of the tool life are very important both from the scientific and industrial perspective. In this thesis, tool lives of different helical end mills in milling aerospace grade aluminum alloy Al-7050 which is used in structural parts of aircrafts and aerospace systems are investigated experimentally. This research was sponsored by the Turkish Aerospace Industries (TAI). The workpiece material and milling tools are supplied by TAI. In this research, the forces acting during the milling of Al-7050 are modeled using mechanistic calibration technique taking the bottom edge cutting affects into account. The cutting force model is validated with the cutting experiments conducted on multi-axis CNC milling processes in Mori Seiki NMV5000 DCG. Moreover, the heat generated and temperature distributions in the tool geometry are predicted using the mechanic and thermal modeling methods. The thermal model outputs are compared with the available data in the literature and with the infrared thermal measurements performed in the Manufacturing and Automation Research Center. After the temperature field is established, an analysis on wear is performed. The predicted wear values are also compared with the experimental measurement results. The surface roughnesses of the manufactured parts are measured to observe the effect of wear on the finished part. Besides the scientific analysis on milling mechanics and thermal analysis, this research concludes that by selecting appropriate cutting tools and machining conditions significant saving (up to 85%) on tooling cost in industry is possible.