航空轴承非圆滚道的预变形加工技术

提出了在普通轴承磨床上,利用模具轮廓强制套圈毛坯预变形进行加工的原理和方法。根据非圆滚道的理论轮廓,考虑套圈弹性变形、套圈和模具的接触变形、以及模具本身的弹性变形,给出了超精密模具内轮廓尺寸的反算方法和过程,并对各种模具内轮廓形式产生的波形误差和椭圆度误差进行了比较,分析了加工过程中的磨削力及位置对滚道精度的影响。小批量试制表明:形状和尺寸精度都达到了规定的要求,表面质量得到了很大提高。该方法为降低新型轴承的加工成本、提高生产率和质量一致性提供了可靠的技术途径。

预变形加工在横梁加工中的应用

GSⅡ—6000数控切割机是我公司自行研制生产的一台用于钢板下料的新型数控机床。 该机床横梁跨度达6m,横梁为钢板焊接结构,横梁加工完后在精度验收时发现,横梁在重力作用下,自然下垂量达3mm,如图1所示,无法满足机床的工作精度需要。

Machining distortion prediction of aerospace monolithic components

To predict the distortion of aerospace monolithic components, a model is established to simulate the numerical control (NC) milling process using 3D finite element method (FEM). In this model, the cutting layer is simplified firstly. Then, the models of cutting force and cutting temperature are established to gain the cutting loads, which are applied to the mesh model of the part. Finally, a prototype of machining simulation environment is developed to simulate the milling process of a spar. Key factors influencing the distortion, such as initial residual stress, cutting loads, fixture layout, cutting sequence, and tool path are considered all together. The total distortion of the spar is predicted and an experiment is conducted to validate the numerical results. It is found that the maximum discrepancy between the simulation results and experiment values is 19.0%