How To Maintain Optimal Coolant Quality By Removing Tramp Oils

How To Maintain Optimal Coolant Quality By Removing Tramp Oils

How To Maintain Optimal Coolant Quality By Removing Tramp Oils

Tramp oils, common contaminants found in the coolants used by metalworking manufacturing industries, can lead to a range of problems, from production downtime to decreased parts quality. Tramp oils can cause bacterial growth, break down metalworking fluid emulsions, reduce tool life, and pose health hazards to workers. Therefore, removing tramp oils from coolants is critical for maintaining high performance in machining operations.

How To Detect Tramp Oils

There are three main types of tramp oils:

  1. Free-floating tramp oil: Tramp oil that freely floats on the surface of the system.
  2. Dispersed tramp oil: Mechanically distributed throughout the fluid, which can eventually float and become surface oil.
  3. Emulsified tramp oil: Tramp oil that is dispersed within the fluid in a stable emulsion.

Each type of tramp oil can be detected in several ways:

  1. Visual Inspection:
    • Check for tramp oil contamination visually. Look for an oily layer on the fluid surface or residue on machine parts. Tramp oils can leave visible marks.
  2. Concentration Measurement:
    • Measure the concentration using an acid split test to separate the emulsion's oil and water phases, or use a handheld refractometer. An acid split test involves adding acid to a sample, which causes the emulsion to break and separate into oil and water layers, allowing for measurement of the oil content.
  3. Odor Detection:
    • Check for an oily or burnt odor from machines, which can be a sign of tramp oil contamination. Degraded oils can produce a distinct smell due to oxidation or thermal degradation.
  4. Performance Monitoring:
    • Monitor the performance of machine operations. Tramp oil contamination can reduce machine efficiency and performance, often indicated by increased tool wear, poor surface finish, or higher operating temperatures.

What Are Tramp Oils

Tramp oils are waste oils that originate from leaks in hydraulic systems, oils used for lubrication, bearing greases, and other greases and oils used in and around the machine and manufacturing process. The contamination can cause serious, adverse effects on water miscible cutting and grinding fluids, leading to a wetting loss, and degrading the workpiece surface finish and tool lifespan. They also reduce the fluid's cooling effect, impacting tool life further. Tramp oils may impede filtration and contribute to unfavorable residues on machine tools and workpieces. Environmentally, tramp oils contribute to smoke and oil mist and stimulate the growth of bacteria. 

It is highly recommended that tramp oil contamination be kept to a minimum. Repairing leaks as soon as they are found is the best way to keep tramp oils out of the fluid stream. Generally, high tramp oil levels will affect a product's cleanliness, filterability, mildness, corrosion, and rancidity control. Many mechanical methods exist to minimize leaks and remove oil. It is critical to remove tramp oils as soon as possible. 

How To Remove Tramp Oils

Luckily, there are numerous techniques and devices available to remove tramp oils. There are two basic types of tramp oil separators: skimmers and coalescers.

Skimming Devices:

  • Skimming devices for metalworking generally consist of belt, suction, disk, and tube skimmers. These tools efficiently remove tramp oils floating on the surface within a holding tank or machine sump. Skimmers are best used on a calm surface with minimal agitation.


  • Coalescers utilize contact time on surfaces to gather small droplets and transfer the oil to an adjacent surface where the droplets become progressively larger and readily float to the surface. Coalescers are most effective when tramp oils are not readily soluble in the working solution.

Using The Right Tramp Oil Removal Tools

Tramp Oil Skimmers helps machinists remove tramp oils from coolants whether they are free-floating, agitated, dispersed, or loosely emulsified. They are suitable both for single or multiple machines, and helps maintain the integrity of fluids used in metalworking manufacturing processes.

EdjeTech's Tube Mill Coolant Recycling System is designed for tube milling facilities. It excels at removing tramp oils and metal fines, which helps extend the lifespan of coolants and reduces oil contamination risks in the fluid stream. Its filtration technology can remove tramp oils, and metal and non-metal particles down to 1/4 of 1% by volume. 

Tramp Oil Separation System (T.O.S.S) or Oil Water Separation System is a high-efficiency coalescing system. The separator system enhances the longevity and performance of machining fluids by removing tramp oils and suspended solids from water-based coolants, synthetic and semi-synthetic cutting fluids, and wash water systems, tackling the core issues of operational downtime and efficiency head-on. T.O.S.S removes tramp oils to below 0.5% by volume.

Industrial CNC Coolant Filtration System (C.R.O.S.S) is tailored for high-volume CNC machine centers, precision grinding operations, and milling processes, and suitable for facilities where space optimization is critical. It filters all forms of tramp oils, metals, and other contaminants and helps extend the coolant life. The C.R.O.S.S ensures to remove tramp oils down to 0.25% by volume.

Remove Tramp Oils From Your Fluid Stream Today

Maintaining optimal coolant quality by effectively managing tramp oils is essential for any metalworking operation. With the right detection methods, removal techniques, and tools, you can significantly enhance your machining performance, reduce operational downtime, and ensure a safer working environment.

Investing in advanced tramp oil removal systems like EdjeTech's Tube Mill Coolant Recycling System, Tramp Oil Separation System (T.O.S.S), and Industrial CNC Coolant Filtration System (C.R.O.S.S) can help you achieve these goals. Our systems are designed to meet the specific needs of various machining processes, ensuring efficient and effective tramp oil management.

Key Benefits:

  • Reduce new fluid purchases by up to 80%
  • Cut waste disposal costs by up to 90%
  • Achieve ROI within 6-9 months

For personalized advice on the best tramp oil removal solutions for your facility, contact us today for a free consultation. Our experts are ready to help you improve your coolant quality and overall operational efficiency.

Reduce Waste, Increase Production & Profit Margins

For over 38 years, EdjeTech Services has been at the forefront of industrial fluid management, specializing in advanced coolant filtration systems and expertise extending to both oil-based and water-based fluids.

Committed to reducing operational expenses, our tailored solutions across various industries are designed to maximize efficiency and ensure a significant return on investment for our clients.

Discover how EdjeTech Services' filtration systems can transform your fluid management and drive cost savings.