Removing tramp oil to extend coolant life and reduce costs

November 1, 2021 3:27 pm

CNC machine operators are constantly striving to reduce costs and improve finished part quality. 

Whether “tramp” oil finds its way into coolant, or accumulates in parts washing baths, oil can wreak havoc on machining operations.  Tramp oil in coolant can clog lines and spray nozzles, shorten tool life, stain work pieces and lead to inaccurate tolerances.  The cost of replenishment and disposal of coolant is also substantial.  In parts washing, oil that is not removed accumulates and contaminates wash solutions, resulting in frequent bath recharging, and poor adhesion during painting or plating.

However, many may be overlooking a significant opportunity to accomplish both mandates by focusing on improving the process of removing oil generated in the various stages of machining processes.

Removing tramp oil to extend coolant life

Tramp oils including hydraulic oil, lubricating oil and greases, and protective metal coatings can be generated by continuous small leaks from equipment, or a one-time occurrence, such as a hydraulic line break.

However, for machine tools to perform at peak efficiency, the coolant must be free from contamination. When tramp oils combine with other contaminants in coolant, they can form a sticky substance that clogs lines and sprays.  When oil contaminated coolant hits the tool, the cooling effect of the coolant is reduced, causing shorter tool life, product staining, inaccurate tolerances, and a smoky atmosphere in the plant.

Tramp oils in coolant are also a breeding ground for bacteria and can cause problems ranging from unpleasant odour to employee skin rashes.  If not removed, bacteria also slowly destroy the coolant. Removing tramp oil extends the life of the coolant, allowing it to be used much longer.

Oil Skimmers and Separators

One cost effective and simple method to combat tramp oil is a surface oil skimmer that mounts on the coolant reservoir and continually draws off surface oil.  For this to be an option, the tramp oil must separate from the coolant and gather on the surface.

Some efficient oil skimmers use a Free-Floating Collector Tube that actively and continuously removes the oil and grease as it rises to the surface of the water.  As the tube moves across the surface, oil adheres to the outside, and then the tube is drawn through a series of ceramic scrapers that constantly remove the oil, which then drains by gravity into a collection vessel. The tube skimmer operates continuously with minimal attention or maintenance.  Tube Skimmers come in sizes and configurations to fit all applications, from small individual sumps to large holding tanks.

For more info, visit: www.oilskim.com.