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.

The presented results are part of more extensive experiments, which aim to verify the reliability of the results provided by CAM systems in the production of parts with shaped surfaces. The article deals with the comparison of production times obtained from programming and simulation systems with real production times. For production planning and organization processes, information on estimated production time is an important input. A free-form sample was designed for the experiment. Finishing of the sample surfaces was accomplished by 3-axis and 5-axis milling using three different strategies. The machining times obtained by the simulation in the CAM system, the times from the simulation mode of the machine control system and the real machining times were evaluated. Data discrepancies were shown, with in almost all cases the real machining times being longer than the times given by the simulations. The results were supplemented by outputs from software that optimizes the feed during milling thus reducing the production time. The tests proved the validity of its use.

The article deals with the comparison and evaluation of finishing cutter path strategies when applied to one of the difficult to cut material such as Ti-alloy. The titanium alloy has been increasingly used for high performance application for oil and gas, aerospace, energy, medical and automotive industries. The importance of milling strategies outgoing from their impact on the economic aspects of production, realized using CNC machines. A planar sample was designed for the purposes of the experiment, enabling finishing cutter path strategies for shaped surfaces. Three cutting strategies were involved and compared- spiral, constant Z and line feed. For assessment of the effect of the cutting strategies three different feed rate were used. Comparison of simulated cutter path strategies and machined surface were visually inspected as well as measured surface roughness were evaluated. The constant Z cutting path strategy was found as suitable cutting strategy from point of view of surface roughness.