辅助筋条厚度对2219陶铝材料数铣短壳壁板成形精度的影响

Influence of auxiliary rib thickness on forming accuracy for CNC milling short shell panel of 2219 ceramic-aluminum material

以运载火箭贮箱用2219陶铝材料数铣短壳壁板为研究对象,通过分析产品结构特点,利用四轴滚弯方式分区成形凸台区及网格区,合理控制上、下轴夹持间距及下压量,探究航向上、下端辅助筋条厚度设计对成形工艺参数及型面精度影响的机制,以实现2219陶铝材料的工程化应用。结果表明:同等模块曲率半径下,辅助筋条厚度影响材料的塑性流动及相对弯曲半径,受到弯曲三向应力,制约成形工艺参数及产品精度。辅助筋条厚度为6 mm时比厚度为5 mm时产生更大比例的塑性变形,更容易达到成形曲率要求,影响显著,但对弧度成形精度影响较小。当数铣短壳壁板航向上、下端设有3条辅助筋条时,控制辅助筋条厚度为5 mm,可控制弧度间隙在2 mm以内、焊接区直线度在1.5 mm以内、网格区直线度在2.5 mm以内。

Taking the CNC milling short shell panel of 2219 ceramic-aluminum material in the launch vehicle tank as research object,through the analysis of product structure characteristics,the boss and grid areas were partitioned and formed by four-axis roll bending meth-od,and the clamping gap of upper and lower shafts and the pressing amount were reasonably controlled.Then,the influence mechanism for the thickness of auxiliary ribs at the upper and lower ends of heading on the forming process parameters and the profile accuracy was explored to realize the engineering application of 2219 ceramic-aluminum material.The results show that the plastic flow of materials and the relative bending radius are influenced by the thickness of auxiliary ribs under the same radius of module curvature,and the forming process parame-ters and the product accuracy are restricted by three-dimensional stress in bending.In addition,when the thickness of auxiliary ribs is 6 mm,it produces a larger proportion of plastic deformation than that when the thickness is 5 mm,and it is easier to meet the requirements of form-ing curvature,which has a significant impact,but it has little effect on the arc forming accuracy.Finally,when there are three auxiliary ribs with the thickness of 5 mm at the upper and lower ends of heading for the CNC milling short shell panel,the arc gap clearance,the straightness of welding zone and the straightness of grid area are controlled within 2,1.5 and 2.5 mm,respectively.