Extending the possibilities of cryogenic assisted grinding

扩展低温辅助研磨的可能性

• 批准号: 440394762
• 负责人: Professor Dr.-Ing. Jan C. Aurich
• 金额: --
• 依托单位: São Paulo Research Foundation (FAPESP)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/440394762?language=en
• 关键词: Extending; possibilities; cryogenic; assisted; grinding

In grinding operations, metal working fluids (MWF) are used to minimize the heat-associated problems such as surface cracks, burning, and tensile residual stresses. Filtration, recycling, and disposal of MWFs are additional cost factors. All these factors have led to intensify the research to minimize or eliminate the MWF from the manufacturing process. In response to these requirements, methods such as minimum quantity lubrication (MQL) and application of cryogenic fluids as MWF were developed. In the majority of the cases, cryogenic fluids are applied, similar as conventional MWF, continuously throughout the process. The inert nature and immediate evaporation of cryogenic from working environment makes benefit in terms of filtering, recycling and disposal costs. Drawbacks are the additional cost of the cryogenic delivery system and safety requirements. At this juncture, our collaborator (Brazilian research group) has developed a method of dry grinding with precooled parts. In this method, the parts to be finished will be cooled in a cryogenic medium, and then subjected to grinding operation without any MWF supply. However, the performance of the precooled parts in dry grinding depends on the shape, size, and dimensions of the part. Hence, in this collaborative project, investigations will be carried out to determine the advantages and disadvantages of the precooled parts in the dry grinding mode with a wide range of variables (different grinding processes, various workpiece dimensions), which were not given an attention so far. Two types of grinding process will be considered. The German research group will focus on surface grinding, whereas the Brazilian research group will focus on cylindrical plunge grinding. To investigate the cooling method, selection criteria and heat transfer simulations will be done together based on the part geometry, wheel and workpiece thermal properties to classify the suitable workpiece dimensions for a precooling method and in-situ partial precooling method. In the in-situ partial precooling method, only a portion of the part is precooled. Based on simulation results, workpieces will be classified as large (not suitable for precooling method) and short (suitable for any cooling method) type, and accordingly, possible cooling methods will be applied. During this project, responses related to process (e.g., forces, temperature, power, wheel wear, G-ratio) and ground surface (e.g., microstructural changes, micro hardness, surface roughness) will be examined and discussed. By comparing the benefits and limitations of each cooling method, a comprehensive knowledge on the capabilities of cryogenic application in grinding can be achieved. Ultimately, unrestricted exchange of the research results will lead to strengthen the relationship of this binational research group.

在研磨操作中，金属工作流体（MWF）用于最大程度地减少热相关问题，例如表面裂纹，燃烧和拉伸残留应力。 MWF的过滤，回收和处置是其他成本因素。所有这些因素都导致加强研究，以最大程度地减少或从制造过程中消除MWF。响应这些要求，开发了诸如最小量润滑（MQL）和低温流体在MWF中的应用。在大多数情况下，在整个过程中都使用低温流体，与常规MWF相似。惰性性质和从工作环境中的低温蒸发在过滤，回收和处置成本方面受益。缺点是低温输送系统和安全要求的额外成本。在这个关头，我们的合作者（巴西研究小组）开发了一种用预冷零件干燥的方法。在这种方法中，要完成的零件将在低温介质中冷却，然后进行磨削操作而无需任何MWF供应。但是，干燥磨削中预冷部分的性能取决于零件的形状，大小和尺寸。因此，在这个协作项目中，将进行调查，以确定干燥磨削模式下的预冷零件的优点和缺点，这些变量范围很广（不同的磨削过程，各种工件尺寸），到目前为止尚未引起注意。将考虑两种类型的研磨过程。德国研究小组将重点放在地面磨削上，而巴西研究小组将重点关注圆柱形柱塞。为了研究冷却方法，将根据零件几何形状，车轮和工件热特性一起进行选择标准和传热模拟，以将适当的工件尺寸和原位的部分预冷方法分类。在原位的部分预冷方法中，只有一部分零件的预冷。基于仿真结果，工件将被归类为大（不适合预冷方法）和简短（适用于任何冷却方法）类型，因此，将应用可能的冷却方法。在此项目中，将检查和讨论与过程（例如力，温度，功率，车轮磨损，G-Ratio）和地面（例如，微结构变化，微硬度，表面粗糙度）有关的响应。通过比较每种冷却方法的好处和局限性，可以实现有关磨削能力的全面知识。最终，不受限制地交换研究结果将导致加强该双性研究小组的关系。