Nourani Sia A, Pons Dirk J, Symons Digby, Zhang Senlin
Department of Mechanical Engineering, University of Canterbury, Christchurch 8140, New Zealand.
Materials (Basel). 2022 May 20;15(10):3674. doi: 10.3390/ma15103674.
NEED-The effect of dimensional variability of sheet thickness (tolerance) and tool misalignment is poorly understood for the clinching process. Finite element analysis (FEA) is valuable but requires a lot of and is difficult to verify in this situation due to the asymmetrical geometry and nonlinear plasticity. OBJECTIVE-The objective of this work was to determine the effect of thickness tolerance, tool misalignment and sheet placement (top vs. bottom) in the clinching process, by use of analogue modelling with plasticine. METHOD-Experiments used a scaled-up punch and die, with plasticine as the analogue. Thickness tolerances were represented by sheet thicknesses of 11 and 7 mm, 12 and 8 mm, 8 and 12 mm and 13 and 9 mm for upper and lower sheets, respectively. Two types of lubricant were tested between sheets: glycerine and silicone oil. Angular variability was also introduced. Measured parameters were interlock (also called undercut) and neck thickness. Analogue results for deformation were compared with microscopy of metal clinching. FINDINGS-The results reveal that the multiscale analogue model is an efficient tool for studying the effect of dimensional deviation on a clinch joint. Thickness tolerance showed a critical relationship with interlock, namely a reduction to about half that of the nominal, for both maximum and least material conditions. Increased angular misalignment also reduced the interlock. Compared with glycerine, silicone oil tests showed reduced interlock, possibly the result of a lower coefficient of friction. ORIGINALITY-This work demonstrates the usefulness of analogue modelling for exploring process variability in clinching. The results also show that significant effects for sheet placement are ductility, lubricant (friction), thickness of samples and tool misalignment.
需求——对于压铆工艺，板材厚度的尺寸变化（公差）和模具错位的影响尚未得到充分理解。有限元分析（FEA）很有价值，但由于几何形状不对称和非线性塑性，在这种情况下需要大量计算且难以验证。目的——本研究的目的是通过使用橡皮泥进行模拟建模，确定厚度公差、模具错位和板材放置方式（上板与下板）在压铆工艺中的影响。方法——实验使用了放大的冲头和模具，以橡皮泥作为模拟材料。上、下板材的厚度公差分别用11毫米和7毫米、12毫米和8毫米、8毫米和12毫米以及13毫米和9毫米的板材厚度来表示。在板材之间测试了两种润滑剂：甘油和硅油。还引入了角度变化。测量参数为互锁（也称为底切）和颈部厚度。将模拟的变形结果与金属压铆的显微镜观察结果进行比较。结果——结果表明，多尺度模拟模型是研究尺寸偏差对压铆接头影响的有效工具。厚度公差与互锁呈现出关键关系，即在最大和最小材料条件下，互锁均降至标称值的约一半。角度错位增加也会降低互锁。与甘油相比，硅油测试显示互锁降低，这可能是摩擦系数较低的结果。创新性——本研究证明了模拟建模在探索压铆工艺变化方面的有用性。结果还表明，板材放置方式的显著影响因素包括延展性、润滑剂（摩擦力）、样品厚度和模具错位。
