滑动摩擦接触对母线弯曲成形质量的影响

目的 研究滑动摩擦接触对1060纯铝母线弯曲成形质量的影响，得到表面质量更好的工件，降低废品率。方法 采用自行设计的V形三点式自由弯曲成形的摩擦力测试装置，通过更换不同表面粗糙度的凹模圆角、不同润滑介质以改变接触状况，进行一系列摩擦试验。通过钨灯丝扫描显微镜获得板料弯曲件表面微观形貌图，通过MATLAB软件对所采集的数据进行曲线处理。结果 得到不同粗糙度的凹模圆角以及不同润滑介质条件下的弯曲力-行程曲线。经测定，凹模圆角表面光滑时，无润滑状态下，最大摩擦力约为440 N；采用聚乙烯薄膜作为润滑介质，最大摩擦力约为100 N；采用聚四氟乙烯薄膜作为润滑介质时，最大摩擦力约为20 N。凹模圆角表面粗糙时，无润滑状态下，最大摩擦力约为235 N；采用聚四氟乙烯薄膜作为润滑介质时，最大摩擦力约为28 N。结论 添加润滑介质可以有效降低板料与凹模圆角之间摩擦力大小，进而提高弯曲件表面成形质量。滑动摩擦条件下，无论光滑还是粗糙的凹模圆角，采取润滑措施均能有效提高弯曲成形工件的表面质量，且聚四氟乙烯薄膜作为润滑介质时，得到的板料表面质量最好。

Influence of Sliding Friction Contact on the Quality of Busbar Bending Forming

The work aims to study the effect of sliding friction contact on the bending quality of 1060 pure aluminum busbar to get better surface quality and reduce reject rate. The self-designed friction force testing device for V-shaped three-point free bending forming was adopted to carry out a series of friction tests by changing the corner of the concave die with different surface roughness and different lubricating media to change the contact condition. The surface micro structure of sheet metal bending parts was obtained by tungsten filament scanning microscope. The collected data were fitted by MATLAB software. The curves of bending force and stroke under different roughness of concave die and different lubricating media were obtained. When die fillet surface was smooth and there was no lubrication state, the maximum friction size was about 440 N. When polyethylene film was used as lubricating medium, the maximum friction force size was about 100 N. When polytetrafluoroethylene film was used as lubricating medium, the maximum friction size was about 20 N. When the round angle surface of concave mould is rough, the maximum frictional force was about 235 N without lubrication. When polytetrafluoroethylene film was used as lubricating medium, the maximum frictional force was about 28 N. The addition of lubricating medium can reduce the friction between the plate and the concave die corner effectively, and then improve the forming quality of the surface of the bending parts. Under sliding friction conditions, the surface of bending parts can be effectively improved by the lubrication measures, whether concave die corner is smooth or rough, and the quality of the surface is the best when the PTEF film is used as the lubricating medium.