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The main goal of our paper is to compare the results obtained using full factorial experiments with different combinations of one factor levels. On the example of multipass wire drawing, we will show how the choice of levels of factors can affect the final result of the experiment, especially in view of the determination of the significant factors and their interactions. We will demonstrate how important the selection of each factor level is on the final result of the experiment. The experimental material was a drawn wire of 5.5 mm diameter of C78DP steel. The wire was drawn from the diameter of 5.5 mm to 2.5 mm using a straight-through single-block KOCH KGT 25-E wire drawing machine. The total reduction was 79.3 %. The drawing dies of tungsten carbide had approach angles of 8° and 12°. Two ways of descaling (mechanical and chemical) were used. A total of three uniform pass schedules were used with different single-pass reduction (23, 27 and 32.6 %). It gives us three individual experimental plans of design of experiments (DOE) in total with the following variations of one-pass strain levels: DOE1 23 – 27 %, DOE2 23 – 32.6 % and DOE3 27 – 32.6 %. The monitored depended variable is the number of bendings to fracture during the reverse bending test. All DOE were evaluated using graphical methods. The significant factors and their interactions were determined and compared for all DOE mutually.
Keywords: Design of Experiments, wire drawing, patented wire, descaling, die geometry, pass reduction© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.