Tube Bending Experiment Dataset

In order to obtain the data required for training and testing ML algorithms, a total of 150 tube bending experiments were performed. All the tubes were made of AISI 316 austenitic stainless steel material and the bending radius was determined as 72.9 mm. Bending parameters were selected as (1) tube outer diameter, (2) tube wall thickness, (3) bending angle, (4) the distance of the mandrel to be used to the bending axis, and (5) mandrel type. The parameter values selected for the experimental test study are given dataset. The test results were either ACCEPT (1) or REJECT (0). Before beginning the tests, in order to avoid any confusion during and after the study, the parameter values were coded on the samples. In order to carry out the experimental tests in the data list, die sets (bending die, pressure die, clamping die and suitable mandrel type) appropriate for the determined tube types were connected to the CNC machine, respectively; then the final adjustments were made before the bending process. A great attention was paid to adjust the distance of the mandrel to the bending axis. For each test to be performed, 3D model of each tube to be bent was designed using Siemens NX drawing software in accordance with the specifications determined in the experiment list. The assembly drawings were created and the intersection coordinates of the principal axes of the designed tubes were listed. Then the codes were written to perform the bending operations on the CNC bending machine and manually entered in the control unit of the CNC machine; in addition, simulations were performed to check the risk of the workpiece hitting the workbench. After gaining the confidence of a safe bending, the workbench was made ready for the process. The tubes were cut on the band saw according to the layout sizes in the technical drawings. Machining burrs formed on the cutting surfaces of the cut tubes were removed by using appropriate sandpaper in the deburring machine. Before starting the bending process, hydraulic oil was applied to the mouth of the pipe and the arbor of the CNC to provide lubrication. Then, the tube was passed through the mandrel connected to the CNC machine and given the start, the bending process started. The experimental study was carried out on an Italian Macri 6-axis CNC tube bending machine (Ø18mm to Ø60mm diameter bending capacity). Upon the completion of the process, the bench was brought to the safe position and the bent tube was taken out of the bench. The conformity of the bent tube to the manufacturing technical drawing was checked. According to the quality control, the bending process was considered either successful for the samples free from measurement errors and visual defects (ACCEPT), or unsuccessful for the samples having measurement errors and/or visual defects (REJECT). The number “1” was written on the accepted test samples and “0” on the rejected test samples, and the results were also recorded in the experimental data list.