基于CAM/CNC集成的航空大型薄壁件数控加工在机刀轨调整方法

航空大型薄壁零件刚性弱,加工过程中易产生超差变形,需要对零件进行在机检测,并将检测数据反馈给CAM系统进行拟合并调整刀轨。以上过程需要在不同部门和系统间进行切换,严重影响了生产效率。针对以上问题,提出了一种基于CAM/CNC集成的航空大型薄壁件数控加工在机刀轨调整方法。建立了CAM/CNC集成框架,并构建了用于CAM/CNC间信息传递的动态特征信息模型,基于CAM系统离线生成特征理论中间状态,基于CNC系统建立特征实际中间状态检测点同理论中间状态的映射关系。通过分析理论厚度和实际厚度,确定特征中间状态的变形情况。针对变形导致特征中间状态加工余量无法包络符合公差要求的最终加工状态的情况,进行在机刀轨调整。基于所提出的方法开发的航空大型薄壁件数控加工在机刀轨调整系统在某大型航空企业得到了应用验证,可有效避免信息的反复传递,减少了工艺人员的重复劳动,提高了生产效率。

An adjusting method of tool path on machine for NC manufacture of large thin-walled aeronautical part based on integration of CAM and CNC

Deformation is easy to occur during the machining process for the large thin-walled aeronautical part, which has bad rigidity. In this case, on-machine inspection is needed. The inspection points are obtained and fed back to CAM system to fit surface and generate new tool path. The information needs to be transmitted between different departments and system platform during the above process, which reduces the productivity. In order to address the issues above, an adjusting method of tool path on machine for the manufacture of large thin-walled aeronautical part based on the integration of CAM and CNC is proposed in this paper. The frame of the integration of CAM and CNC is built and the dynamic feature information model is also built in this method to transmit information between CAM and CNC system. The theoretical interim state of part feature is generated based on the CAM system offline. The deformation of the feature interim state is confirmed based on the mapping relationship between theoretical interim state and the actual interim state, and the comparison for the theoretical and actual thickness in the CNC system. The tool path is adjusted on-machine for the situation that the final machining status conforming to the requirement of the tolerance cannot be enveloped by the machining allowance of the feature interim state. The system based on the adjusting method of tool path on machine for the manufacture of large thin-walled aeronautical part based on the integration of CAM and CNC is verified in an aviation manufacturing corporation. Using the proposed method, the transmission of information is reduced, the intensity of labor for technologist is decreased and the productivity is increased.