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Employing of complex surfaces in different industries such as aerospace and die and mold is increasing. For milling of such surfaces, considering factors such as strategies and machining parameters which affect the machinability is necessary. The objective of this study is to investigate the effect of different strategies and machining parameters on microhardness of a typical curved surface (convex) of stainless steel 1.4903. The cutting tool used in this study was ball nose end mill coated TiN and the strategies employed were Raster, 3D-offset, Spiral and radial. Design of experiments was done using Taguchi method. The input parameters were cutting speed, feed rate and step over. After conducting experiments, surface layers hardness of milled samples were measured. The results showed that various tool paths have different influence on microhardness of milled surfaces. Regardless of cutting condition, surface hardness after machining in all strategies was more than the primary hardness of the workpiece material. Spiral strategy provided the most hardness and radial strategy the least hardness. In addition, increasing the feed rate, cutting speed and step over, rised surface hardness and step over had least influence on hardness. The most hardness magnitude was reported in cutting speed of 180 m/min, feed rate of 0.18 mm/tooth and step over of 0.7 mm which shows 56 % of increase.

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The milling process is widely used in the manufacturing industry to shape complex geometric parts. Considering the flexibility of the cutting process and the various variables involved, process optimization has become a key issue in achieving higher productivity and quality. To optimize the process planning, it is important to choose a suitable machining strategy. Implementation and selection of tool path strategies and orientations are very important in the machining process, especially in the aerospace and molding industries. The right choice can lead to significant savings in machining time, improvement of work-piece surface quality, and improvement in tool life, thus leading to overall cost reduction and higher productivity. Therefore, this article aims to identify the best strategy in terms of surface roughness and milling time. In this article, Shallow's strategy has been investigated, and the milling of its finishing stage has been studied and compared with three strategies of the milling process, including raster, 3D offset, and raster flat. In this article, the comparison of the strategies in the Powermill software and with the flat-head finger mill, which can grind the floor and the wall simultaneously, has been done. Tool-cutting parameters were considered constant for all tested strategies. Machining quality was evaluated by comparing surface roughness, surface Topography, and dimension control parameters. The results indicate that the Shallow machining strategy has the lowest surface roughness and the best surface quality, and the raster strategy has the highest surface roughness and the worst surface quality in this test.