Owing to the importance of geometrical design of clinching tools, the flat-clinching were investigated numerically and experimentally to determine the optimal geometrical parameters in this study. The geometrical parameters in flat-clinching, including punch corner radius, draft angle of the punch, blank holder corner radius, blank holder radius, and punch velocity, were optimized using the orthogonal experimental design simulation method based on the evaluation of interlocking. The simulation results show that the punch corner radius and the blank holder radius have a significant impact on the clinched joint, whereas the draft angle of the punch and blank holder corner radius have little influence on the clinched joint. The simulation results were validated through an experimental setup testing on material aluminum alloy Al5052. The experimental results have a good agreement with the orthogonal experimental design simulation.

Due to the importance of geometrical design of clinching tools, the clinching process with extensible dies was investigated numerically and experimentally to seek for optimal parameters of clinching tools in this study. The joining parameters, including punch corner radius, sliding distance, die depth and bottom thickness, were optimized using the orthogonal experimental design simulation method based on the evaluation of tensile strength. The simulation results were validated through an experimental setup testing on material aluminum alloy Al5052. The orthogonal experimental design simulation results showed reasonably good agreement with the experimental results. To further investigate the validation of the simulation model, the different bottom thicknesses within a reasonable range of value were studied. The results also indicated that the simulation model could be employed to predict the joint forming by the clinching process with extensible dies.

In order to obtain better quality TA10 pipes, the Boring and Trepanning Association (BTA) deep-hole drilling process is used. However, this type of machining leads to difficult chip removal, tool wear, and poor hole-surface quality. In this study, a deep-hole drilling experiment was conducted on TA10 workpieces using the designed tool with different process parameters, and the process parameters were optimized by machining results with multiple objectives such as chip morphologies, tool wear, hole-axis deflection, and hole surface roughness. The results show that different process parameters have a great impact on the cutting process, with a higher feed resulting in smoother chip removal and a lower spindle speed resulting in lighter tool wear and less hole axis deflection. When the spindle speed is 145 r/min and the feed is 0.12 mm/r, the machined TA10 pipe meets both the accuracy requirement of roughness and the machining efficiency.

In the deep-hole boring process on pure niobium tube, there exist some problems including serious tool wear, tough chips, and poor surface quality. In order to bore high-quality deep holes on rolled niobium tube, the cutting tool structure and boring process parameters suitable for machining rolled niobium tube were designed and two experimental schemes were proposed. The results showed that the geometric parameters of the cutting tool and process parameters have important influences on the tool wear, chip morphologies, hole-axis deflection, and hole surface roughness. By adjusting the geometric parameters of the cutting tool and boring process parameters, reasonable geometric parameters of the cutting tool and boring process parameters were obtained.

The precise measurement of inner dimensions and contour accuracy is required for deep-hole parts, particularly during the manufacturing process, to monitor quality and obtain real-time error parameters. However, on-machine measurement is challenging due to the limited inner space of deep holes. This study proposes an automatic on-machine measuring apparatus for assessing inner diameter, straightness, and roundness errors. Based on the axial-section measurement principle, an integrated measuring module was designed, including a self-centering mechanism, a diameter measuring sensor, and a positioning reference sensor, all embedded within a control system. On this basis, calculations of the inner diameter, and evaluations of the straightness and roundness errors are presented. Experimental verification is conducted on a blind deep hole with a nominal 100 mm inner diameter and 700 mm depth. Compared with measurements performed on a coordinate measuring machine (CMM), which is limited to a maximum hole depth of 300 mm, the proposed apparatus achieved full-depth on-machine measurements. Meanwhile, the measurement results were consistent with the data obtained by the CMM. The straightness error is considered less than 0.05 mm, and the roundness error is considered less than 0.015 mm. Ultimately, without requiring any additional reference platform, the proposed apparatus shows promise for measuring deep-hole parts on various machine tools, with diameters of no less than 80 mm and theoretically unlimited hole depth.