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Effectively cleaning machined or formed parts is a key step in all manufacturing processes—especially in surface finishing— but too often it is overlooked. Underperformance of cleaning programs results in defects and poor quality of subsequent operations, yet over-cleaning is costly and wasteful. An effectively monitored and proac- tively managed parts cleaning process that delivers reliable performance is designed by addressing the substrates, machining operations and the fluids in the front end of the operation. Based on the severity of the operations, the chemistry of machining fluids (coolants) and drawing and stamping fluids can vary greatly. Light-duty applications such as milling and drilling on cast iron or stamping lighter gauge stock can be performed with lower lubricity fluids. However, more severe operations, such as broaching, threading or gun drilling, with more challenging substrates such as stainless steels, hardened steels, Inconel or titanium, require high lubricity machining fluids. To obtain higher lubricity, formulators include higher levels of oil and often use extreme pressure addi- tives to meet the performance requirements. Even straight oil cutting fluids include additives that affect the cleaning of the resulting parts. Extreme Pressure (EP) addi- tives will significantly boost the lubricity characteristics of coolants and drawing and stamping fluids. BY DAVID M. GOTOFF CHEMETALL Aligning Parts Cleaning with the Metalworking Process Underperforming cleaning programs can result in defects, poor finishing quality. EP additives, at higher temperatures and pressures, plate out on the substrate surface in the cutting or forming process, greatly reducing the coefficient of friction, while depositing residues on the parts. Typically, EP additives are based on phosphorous, sulfur and/or chlorine, and in some cases, in the form of chlorinated paraffin. These compounds, by nature, are more difficult to remove in typical parts washing programs, and need to be addressed in the cleaning process Certain operations create soils that are challenging to remove. Typical grinding fluids contain lower oil content with limited additives or are fully synthetic. This type of compound can be easily cleaned after light milling or drilling. However, in the grinding process, especially when the parts are cast iron or sintered metals, the resulting "swarf" can pose cleaning challenges. The graphite components and extremely small chips are very difficult to remove in typical parts washers, so enhanced cleaning is required. With any machining program, a key to success in the An effectively monitored and proactively managed parts cleaning process that delivers reliable performance is designed by addressing the substrates. 32 NOVEMBER 2015 — pfonline.com PARTS CLEANING