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.为获取机器学习（Machine Learning, ML）算法训练与测试所需的实验数据，本研究共开展150组管材弯曲实验。所有实验管材均采用AISI 316奥氏体不锈钢制成，预设弯曲半径为72.9 mm。本次实验选取的弯曲参数包含五项：(1)管材外径，(2)管材壁厚，(3)弯曲角度，(4)所用芯棒至弯曲轴线的距离，(5)芯棒类型。实验研究所选用的参数值已整理为数据集。测试结果分为合格（ACCEPT）与不合格（REJECT）两类，分别以数字1和0进行标记。正式启动测试前，为避免实验过程中及收尾阶段出现混淆，所有实验样本均已完成参数值编码。为执行数据列表中的各项实验，首先将适配目标管材规格的模具组件（弯曲模具、压料模具、夹紧模具及匹配的芯棒类型）分别安装至数控（CNC）弯管机，随后在弯曲作业前完成最终调试，调试过程中重点校准芯棒至弯曲轴线的距离。针对每一组待执行的实验，均采用Siemens NX绘图软件，按照实验列表中确定的规格设计对应管材的三维模型，生成装配图纸并列出所设计管材主轴的交点坐标。随后编写数控弯管机的加工程序，手动录入CNC控制系统；同时开展仿真模拟以验证工件是否存在撞台风险。确认折弯作业安全无误后，准备作业工作台。管材按照技术图纸中的下料尺寸在带锯上完成切割，随后通过去毛刺机使用适配的砂纸去除切割面形成的加工毛刺。折弯作业开始前，需在管材管口及CNC芯轴部位涂抹液压油以实现润滑。之后将管材穿入连接至CNC设备的芯棒，启动程序并开展弯曲作业。本实验研究在一台意大利产Macri 6轴数控弯管机（管径加工范围为Ø18 mm至Ø60 mm）上开展。作业完成后，将工作台复位至安全位置，取出已弯曲的管材。随后对弯管是否符合制造技术图纸要求进行检验。根据质量管控标准，无测量误差与外观缺陷的样本判定为合格，存在测量误差和/或外观缺陷的样本判定为不合格。在合格测试样本上标记数字“1”，不合格样本标记数字“0”，并将结果记录至实验数据列表中。