Precision is critical to the effective long-term performance of most metal parts, and part of that precision is ensuring a part’s Roughness Average (Ra) value falls within an acceptable range. From primary manufacturing processes to secondary operations, including finishing processes, many stages in the manufacturing of metal parts can introduce foreign metals or other contaminants to the part, or negatively impact qualities such as smoothness, corrosion resistance, and electrical conductivity.
303不锈钢部件，具有EDM-形成的孔 - 电缩进前后（300x放大倍数）。图像COUTRESY能够电磁
Depending on the eventual application and use of your metal parts, different finishing processes, both macro and micro, can be used to ensure the parts perform adequately and have an optimal cycle life. When determining which microfinishing process will perform best for your metal parts, there are three things you should keep in mind:
1. How Microfinishing Impacts Product Performance
Microfinishing是,根据定义,是designed to eliminate very small variations in a part’s metal surface. However, while the irregularities that microfinishing seeks to correct may be small, their impact on the part’s eventual performance and cycle life can be large. For parts that will be used in electronic applications, conductivity is of critical importance. Having a specific Ra value can optimize part performance and help prevent electrical arcing, which can cause serious damage to expensive electrical equipment, preventing it from functioning as intended. Irregularities in the metal surface of a part can interrupt the flow of electricity, causing costly malfunctions and false readings. Adequate microfinishing is of particular importance for electronics used in medical applications, such as MRI machines, where high voltages are present and a damaged machine can cost the hospital valuable revenue.
8620电抛光前后钢插入
The impact of inadequate microfinishing is also pronounced in pneumatic and hydraulic applications, where multiple metal parts are moving in close contact with one another. Having the proper degree of friction is crucial for these machines, and a high Ra average can produce unwanted levels of friction. This friction can then impede the part’s performance and, over time, cause damage that weakens the part and ultimately, shortens the lifespan.
2. Microfinishing Options
在您选择对金属部件最有利的微缺发选项之前，有助于获得对您可用的微疗法选择之间的差异的基本了解。一些最常用的微疗法金属部件的方法包括：
·Mechanical Polishing.机械抛光在车轮和皮带上使用磨料材料来消除薄层金属部件。此过程在实现低RA值方面是有效的，但在很大程度上依赖于操作员，并且不能轻易用于提供精确，一致的结果。在大多数情况下，机械抛光也只能一次在一部分上进行，使其比其他替代品更昂贵。此外，它并不适用于更复杂的复杂部件，与难以访问的区域。
·振动精加工。这种类型的精加工是以堆积的方式在振动碗中进行，其含有各种类型的介质和润滑剂。该过程依赖于介质摩擦来平滑部分表面。这个过程不适合易碎的部件容易变形，并且可能非常耗时。
·电力抛光。电抛光是非常具有成本效益和灵活的过程，可用于一部分或数百万部分。作为电抛光去除一致的，从部分表面去除一致的金属层，微孔改善在批次中的所有部件上一致。除了改进的微细化之外，电力抛光大大提高了耐腐蚀性和除去微生物。此外，电极抛光也可以消除氧化物尺度和从现有程序中的热量，并提供清洁，亮的饰面。
电镀前后螺纹的SEM照片（100x放大倍数）
你知道你的产品的RA值吗？
A metal part’s Ra (roughness average) is the average of a set of individual measurements of a surfaces peaks and valleys. The surface is measured with a profilometer and typically called out in microinches or micrometers. A greater Ra value indicates a greater variance and higher degree of roughness in the surface, and metal parts with a Ra value higher than what is acceptable for their specific application may malfunction, wear, and have a shortened lifespan. Knowing the degree of smoothness necessary for a given metal part should play a role in determining which microfinishing process is best. You should also be aware of the metal part’s Ra value prior to microfinishing and what can realistically be achieved. With .001” (.0005” per surface) material removal, electropolishing can reduce a part’s Ra value by up to 50%.
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Tom Glass is President atAbleElectropolishingwww.able电级策译，世界上最大的电解专家提供电力抛光，钝化，阳极氧化和激光标记服务。能够开电器抛光是一家ISO 9001和13485认证公司，提供各种行业，包括航空航天，医疗设备MFG，饮料，汽车等。
Filed Under:工业自动化
