Tool path planning and chatter avoidance in curved surfaces machining

曲面加工中的刀具路径规划和颤振避免

• 批准号: 5312-2011
• 负责人: Ismail, Fathy
• 金额: $ 1.68万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=568398
• 关键词: Tool; path; planning; chatter; avoidance

The objective of this proposal is to conduct fundamental investigations and to develop strategies for tool path planning in machining of curved surfaces. Such surfaces are encountered in numerous industrial parts like turbine blades, impellers, and tools and dies. Milling operations of these surfaces, especially in the semi-finishing and finishing stages, consume considerable time. A significant value has already been added by the time the part is ready for these operations. Research conducted by the applicant has shown that there is a need for developing tool path strategies to avoid chatter at those later stages while maximizing the metal removal rate and generating the surface at required roughness. A critical factor in developing a chatter model is to include process damping. This damping arises in machining materials, like Titanium, at low speeds. The applicant has successfully developed such model for turning operations and managed to establish the stability lobes analytically. These lobes show the limit width of cut against cutting speed. In this project, the developed iterative approach to establishing the analytical lobes will be extended to milling. The chatter model, including process damping, will then be applied to 5-axis flank milling. The developed chatter model will be integrated with the 3 ½ ½ machining strategy to generate the optimal number of surface subdivisions (patches), and feed directions while avoiding machining instability. In this strategy each patch is machined at fixed workpiece tilt angles. While it leads to higher rigidity and shorter machining time, it is more prone to gouging and interference as the tool moves across patches. In this project these problems will be addressed. The developed chatter model will also be integrated with tool positioning strategies in simultaneous 5-axis machining to optimize the tool path over the entire workpiece surface. The machine kinematics will be taken into account to help schedule the feed rate.All equipment necessary to conduct the experimental verifications is available in the Waterloo 5-axis machining lab.

该提案的目的是进行基础研究并制定曲面加工中刀具路径规划的策略。涡轮叶片、叶轮、工具和模具等许多工业零件都会遇到这种表面。这些表面的铣削操作，特别是在半精加工和精加工阶段，会消耗相当多的时间。当零件准备好进行这些操作时，已经增加了重要的价值。 申请人进行的研究表明，需要开发刀具路径策略以避免后期阶段的颤动，同时最大化金属去除率并生成所需粗糙度的表面。开发颤振模型的一个关键因素是包含过程阻尼。这种阻尼出现在低速加工材料（如钛）时。申请人已成功开发了这种用于车削操作的模型，并成功地通过分析建立了稳定性波瓣。这些凸角显示了相对于切削速度的切削极限宽度。在该项目中，开发的用于建立分析波瓣的迭代方法将扩展到铣削。然后，颤振模型（包括过程阻尼）将应用于 5 轴侧面铣削。 开发的颤振模型将与 3 ½ ½ 加工策略集成，以生成最佳数量的表面细分（补丁）和进给方向，同时避免加工不稳定。在此策略中，每个补片均以固定的工件倾斜角度进行加工。虽然它可以带来更高的刚性和更短的加工时间，但当刀具跨补丁移动时，它更容易出现气刨和干涉。在这个项目中，这些问题将得到解决。 开发的颤振模型还将与同步 5 轴加工中的刀具定位策略集成，以优化整个工件表面上的刀具路径。将考虑机器运动学以帮助安排进给速率。滑铁卢 5 轴加工实验室提供进行实验验证所需的所有设备。