Modelling of time-variant material removal functions for abrasive subaperture polishing

磨料子孔径抛光时变材料去除函数的建模

• 批准号: 387743003
• 负责人: Dr.-Ing. Oltmann Riemer
• 金额: --
• 依托单位: Abteilung Fertigungstechnik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/387743003?language=en
• 关键词: Modelling; time; variant; material; removal

The objective of this project is the development of time-variant material removal functions for abrasive subaperture polishing for the machining of optics and precision parts. This will enable a targeted shape correction with minimal material removal and increase the achievable production accuracy and process reliability. Previous approaches focus on time-consistent material removal functions based on the Preston equation. Although this dwell time controlled removal functions allow a process time saving of up to 35%, they have the disadvantage of an inevitable basic removal, meaning that material has to be removed in any case. In order to remove no material, the polishing tool would theoretically have to be moved infinitely fast over the workpiece. A time-variant removal function allows minimizing or even avoiding this basic removal, which in turn leads to a reduction of process time. For the development of such a removal function, the modeling of a novel polishing algorithm or process control is necessary. Therefore, the material removal must be quantified first, according to significant process parameters such as pressure, nominal removal depth and relative speed. On the basis of these experimental results, specific removal functions will be derived, which are proven by modeling. The underlying model is also based on the Preston approach. However, it is extended by temporally variable terms and thus a time-variant removal function is generated. Main focus is the model description of the variable polishing pressure as well as the variable relative speed. The wear of the polishing tool will also be integrated into the model, since wear also depicts a change in the removal function over time. Part of the modeling will consist in minimizing the deviation between the desired and the actual material removal, i.e. the deviation between the desired and the actual surface. This optimization task will provide the optimal parameter constellation for the individual case. Due to the short computing times, at first a two-dimensional model will be evolved, before a substantially more complex, applicable three-dimensional model is derived.

本计画的目标是发展时变材料去除函数，以应用于光学元件及精密零件的研磨子孔径抛光。这将实现有针对性的形状校正，最大限度地减少材料去除，并提高可实现的生产精度和工艺可靠性。以前的方法集中在时间一致的材料去除功能的基础上的普雷斯顿方程。虽然这种停留时间受控的去除功能可以节省高达35%的处理时间，但它们具有不可避免的基本去除的缺点，这意味着在任何情况下都必须去除材料。为了不去除任何材料，抛光工具理论上必须在工件上无限快地移动。时变去除功能允许最小化甚至避免这种基本去除，这反过来又导致处理时间的减少。为了开发这种去除函数，需要对新的抛光算法或工艺控制进行建模。因此，必须首先根据重要的工艺参数，如压力、标称去除深度和相对速度，对材料去除进行量化。在这些实验结果的基础上，将推导出具体的去除函数，并通过建模加以证明。基础模型也是基于普雷斯顿方法。然而，它是由时间变量项扩展，从而产生一个时变去除函数。重点是可变抛光压力以及可变相对速度的模型描述。抛光工具的磨损也将被整合到模型中，因为磨损也描述了去除函数随时间的变化。建模的一部分将包括最小化期望的和实际的材料去除之间的偏差，即期望的和实际的表面之间的偏差。该优化任务将为个别情况提供最佳参数星座。由于计算时间短，首先将演变成二维模型，然后再导出更复杂的适用三维模型。