Freeform surfaces are present on an increasing number of engineering products. Three- and multi-axis computer numerical control milling machines are commonly used for improved production. Computer-aided manufacturing (CAM) systems are used almost exclusively for the creation of programs for a variety of machining centers. This study compared the quality of freeform surfaces made by 3- and 5-axis milling using three commonly used strategies (linear, offset, and spiral). The CAM system-predicted surfaces were also compared with the actual surfaces. A test sample with a freeform surface was used for the experiments. Considering the size and distribution, the discrepancy between the predicted surface deviations and the deviations in the produced samples was proven. Maximum negative surface deviations, when 5-axis milling, employed linear and spiral strategy of 29% and 71% less than those produced by the 3-axis milling. On the contrary, positive deviations were 48% smaller. A comparison of the scans showed that the two strategies (linear and spiral) yielded better results for 5-axis milling, and the offset strategy was better for 3-axis milling. Evaluation of the achieved surface roughness showed that the milling method did not significantly affect the surface quality in the linear strategy. However, other two strategies (offset and spiral) achieved better results with 5-axis milling compared to 3-axis milling. The proposed method of evaluating the accuracy of machined free form surfaces can be used in experimental as well as production activities.

Free-form surfaces in the automotive or aviation industry where the future shape of the product will contain complex surfaces raises the question of how to achieve the necessary shape of the required quality in the milling process. One of the methods of their production is the use of 5-axis milling, in which it is necessary to consider not only the input data of the process itself, but also the methodology for evaluating the desired results. Correctly answered questions can thus facilitate the choice of the inclination of the tool when machining parts of the surfaces defined in the experiment. The primary goal of the paper was to monitor the influence of tool inclination on the quality of the machined surface and effective cutting speed by evaluating surface roughness and surface topography. The experiment was designed to show the effect of different tool positions while the feed per tooth f_z for the finishing operation remained constant. The best result in terms of surface quality was achieved with a tool inclination of 15° in the cutting process. The most unfavorable result was obtained with a tool axis inclination of zero degrees due to unfavorable cutting conditions.

The article deals with the comparison and evaluation of milling strategies, which are available in CAM systems and are used for the production of components with freeform surfaces. For the purpose of the experiment a test sample with a repeating shape feature was designed. First half of the test sample shape features were machined using 3-Axis milling strategies while second half was performed with strategies available on 5-Axis CNC machining centre. Simulated machining times as well as virtually machined surfaces using color maps with deviation values were evaluated by employed CAM software. Obtained data was used to evaluate the performance of 3-Axis and 5-Axis milling centre both individually and mutually. These results will be used to compare software data with data obtained from real sample production. The main goal is to verify the reliability of the results provided by CAM systems in the production of parts with freeform feature surfaces.

Reducing production costs during machining processes can be implemented in several ways, including various methods of cutting parameters optimization. The aim of the described research was to evaluate the effectiveness of software that optimizes the NC (Numerical Control) code generated from a CAM (Computer Aided Manufacturing) system. The experiments were carried out in rough milling. For the experiment, a sample with five pockets was designed and fabricated using the original NC programs from the CAM system and optimized NC programs. Evaluated criteria were the impact on the accuracy of the produced surfaces and degree of production time savings. When using the optimization software, despite more intensive cutting conditions, deviations on the side surfaces of the pockets were reduced from 3 to 23%. On the horizontal surfaces, for two pockets, there was an increase in deviations of a maximum of 7.8%, and for the remaining three pockets, there was a decrease in deviations ranging from 8.3 to 36%. The optimized NC programs achieved time savings ranging from 12.8 to 15.9%. This knowledge is important for manufacturers, as it allows shortening production times and thereby reducing related costs.