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.

在磨削操作中，金属加工液 (MWF) 用于最大限度地减少与热相关的问题，例如表面裂纹、燃烧和残余拉伸应力。 MWF 的过滤、回收和处置是额外的成本因素。所有这些因素都促使人们加强研究，以最大限度地减少或消除制造过程中的金属加工液。为了满足这些要求，开发了诸如最小量润滑（MQL）和应用低温流体作为MWF等方法。在大多数情况下，与传统金属加工液类似，在整个过程中连续应用低温流体。低温的惰性和从工作环境中立即蒸发的特性有利于过滤、回收和处置成本。缺点是低温输送系统的额外成本和安全要求。此时，我们的合作者（巴西研究小组）开发了一种使用预冷零件进行干磨的方法。在这种方法中，待精加工的零件将在低温介质中冷却，然后在没有任何金属加工液供应的情况下进行磨削操作。然而，预冷零件在干磨中的性能取决于零件的形状、尺寸和尺寸。因此，在这个合作项目中，将进行调查以确定预冷零件在干磨削模式下具有各种变量（不同磨削工艺、各种工件尺寸）的优点和缺点，这些变量没有得到关注，因此远的。将考虑两种类型的磨削工艺。德国研究小组将专注于表面磨削，而巴西研究小组将专注于外圆切入磨削。为了研究冷却方法，将根据零件几何形状、砂轮和工件热性能一起完成选择标准和传热模拟，以对预冷方法和原位部分预冷方法的合适工件尺寸进行分类。在原位部分预冷方法中，仅对零件的一部分进行预冷。根据模拟结果，工件将被分为大型（不适合预冷方法）和短型（适合任何冷却方法）类型，并相应地应用可能的冷却方法。在该项目期间，将检查和讨论与过程（例如力、温度、功率、车轮磨损、G比）和地面表面（例如微观结构变化、微观硬度、表面粗糙度）相关的响应。通过比较每种冷却方法的优点和局限性，可以全面了解低温在磨削中的应用能力。最终，不受限制的研究成果交流将加强这个两国研究小组的关系。