How to Manage your Metalworking Fluids

Metalworking fluids may not contribute that much to your manufacturing costs, but when fluids begin to fail or not work as intended, the costs could be astronomical. With the increasing costs of more technological fluids and rising disposal costs, managing your fluid and fluid consumption is more important than ever. Managing your fluids and dedicating a fluid management program could pay dividends by: reducing fluid usage, extending tool life, and improving manufacturing performance.

Monitoring Concentration

Fluid technology has advanced by leaps and bounds over the years and have improved performance for manufacturers. However, these advanced fluids have been engineered to work at specific concentrations. Running a coolant too thin or too rich will limit its ability to do its job. Running a coolant too rich might cause problems of over lubricity, but the main problem is overconsumption of the fluid.

The big problems occur when a fluid is too thin. This means the concentration in the sump is below the manufacturer’s recommendation. The additive packages are designed based on these minimum concentrations and provide enough of each additive to perform its function properly. Less concentrate means fewer biocides, fewer rust inhibitors, fewer emulsion stabilizers, etc. Eventually, the fluid breaks down quicker requiring more frequent change-outs. Some managing fluids, some operators use coolant additives/boosts to improve performance. If you vigilantly monitor concentration, the need for additives will lessen and thus reduce costs.

To monitor concentration, use a refractometer to measure concentration frequently. It is recommended to measure concentration every day or twice a day (depending on your operating schedule). The same person should measure to ensure consistency and ensure reliable measurements. When charging or recharging sumps, using automatic mixers helps ensure concentration is consistent. Remember, do not add just coolant or just water to the sump to balance out concentration. Some facilities use digital coolant monitoring systems to manage concentration, pH, and other factors. Facilities with large coolant systems may benefit from the technology.

Assessing Water Quality

Water comprises 90% or more of the fluid in the sump, thus it is crucial to make sure you are using good water. A common problem is hard water. The ions in hard water can cause chemical instability and increase the likelihood for emulsion splitting. Testing and treating your water is recommended to make sure your sump mix is working as intended. Twin Specialties can test samples of your tap water to ensure it is suitable for use in your metalworking fluid. If your tap water is excessively hard, installing a de-ionized water line is recommended for your facility. Coolant mixers can be connected directly to these lines to ensure proper mixing.

Once your water is deemed suitable, mixing the oil and water is all that is left in preparation. For the best performance and increased emulsion stability, follow the acronym O.I.L.: oil in last. This is an easy to remember acronym that will help you manually mix coolant; automatic mixers already mix using best practices.

Monitoring pH

Alkalinity is critical in the performance of your fluid. If the pH dips too low, it will no longer work and will need to be changed out. If pH drops below 8, it is imperative to raise it immediately. If pH drops below 7, the coolant is lost and must be changed. As the coolant gets more acidic (decreasing pH) you increase your risk of rusting problems. Some additives boost pH, but those may not be needed if you actively monitor your concentration. Monitoring is relatively easy, mix the fluid in the sump to get a more homogenized solution then dip a pH testing strip into the solution. Give the strip some time to change color and then match the strip to a reference sheet (usually provided with the strips). Then you can act accordingly armed with the pH information you need.

Tramp Oil Removal

Slideways and spindles require oil lubricants in order to function properly and ensure proper machining operations. These oil lubricants will leak into the sump and can cause havoc on your metalworking fluid. Some of the lubricant will be emulsified and disrupt the chemical composition of your metalworking fluid. The more oil content in the concentrate, the more likely the tramp oil will be emulsified.

This causes the growth of anaerobic bacteria. This bacterium creates hydrogen sulfide gas, which is the “rotten egg” or “Monday morning” smell that indicates coolant rancidity. The hydrogen sulfide in water also produces acids that drive down pH and alkalinity, which further damages coolant.

Synthetic coolants are excellent in rejecting tramp oils and prevent them from being emulsified. These floating oils can easily be skimmed and removed before causing damage. Using coolants below recommended concentrations limit the tramp oil rejecting additives and can accelerate this process of degradation.

Floating tramp oil can increase oil mist and smoke formation that can damage machines. The tramp oil mist also increases residues on the machine that can clog filters and destroy critical electronic components. Removing floating oil is relatively easy. Installing a skimmer, centrifuge, and/or coalescer will remove tramp oil from the sump and extend your coolants life.

Filtration

Metal fines and chips may find their way into the sump. It is important that they do not remain there and are not cycled through the machine. These fines can cause wear and damage to the machine and workpiece. The fines can build up and create dead-zones when additives are trapped and do not work. The trapped additives cannot work and lead to accelerated coolant breakdown.

Filtration used to be a cost-prohibitive endeavor, but the economics of coolant management and consumption make filters a worthwhile tool. The costs of filtration have come down and filtration technology has improved, thus implementing them will reduce coolant consumption and coolant spending.

Removing Foreign Substances from the Sump

Dirt and other foreign substances can cause problems such as abrasion and pump damage. Filtering solid substances and removing them will improve coolant performance. Sump cleaners might not be fully removed and can cause excessive foaming. If that happens, using a defoamer should alleviate these issues. However, be sure to properly remove the cleaner before recharging the sump. Prevention and proper preparation are usually the best maintenance.

Managing Straight Oil/Neat Oil

Neat oils require much less maintenance than water soluble coolants. This is because neat oils do not require water, which is a breeding ground for bacteria, fungi, and mold. However, there are still a few things that you should do to maintain and extend fluid life. The main thing should be done is filtering metal fines. Removing these metal fines improve finishing and fluid performance.

Takeaways

Given the rising costs and improving technology of metalworking fluids, it is more important than ever to proactively manage your fluids. This can lead to extended use intervals and improved performance. Following these steps will allow your machine to get the most out of these fluids.

Twin Specialties provides a full line of metalworking fluids and additives. Additionally, our sales team will work with you to test your fluids and water to troubleshoot the problem. Contact Twin Specialties for more information about our metalworking fluids, technical expertise, and our testing and sampling program.

5 Factors for Drawing Fluid Selection

In drawing processes, there two main types of lubrication. Firstly, there is fluid or hydrodynamic lubrication, which is the separation of metal surfaces with a continuous film of lubricant that prevents contact of those metal surfaces. Secondly, there is boundary lubrication, which is separating metal surfaces by a film only a few molecules thick.

The drawing process generates extreme pressures and the lubricant needs to perform to ensure proper separation of metal surfaces.

Factors for Drawing Fluid Selection

There are many factors that will affect lubricant selection. We will examine these factors and how they may affect lubricant selection and use. Considering these factors will ensure proper separation and excellent performance.

Type of Metal

Not all metals are alike. The first classification for metals is whether it is ferrous, non-ferrous, or an alloy. The hardness of metal will also be a key factor. Harder metals will require higher pressures, thus higher operating temperatures. A harder metal will need a lubricant that provides excellent cooling to prevent poor finishes or melting. Resistance to rust and corrosion varies metal to metal. Porous metals, such as cast iron, are porous and can rust quickly during annealing. Applications with those kinds of metals may require a lubricant that has rust/corrosion preventative additives.

Severity of Operations

The severity of the operation will be key to determining what kind of lubricant you need. Operations with extreme pressures may require lubricants with extreme-pressure and anti-wear additives to maintain proper lubrication. Operating speeds play a key role in determining the viscosity needed. Higher speeds will require lower viscosities so that the lubricant will adequately circulate. As temperatures rise, viscosity can degrade quickly. When the lubricant becomes too “thin” or “runny”, proper separation may be lost. Some lubricants will include viscosity index (VI) improvers to help maintain proper fluid thickness as temperatures rise.

Tooling

The tooling used in drawing may affect the lubricant selection. Some of the tools used in drawing include:

  1. Dies for cold drawing
  2. Rolls for forming strips and shapes
  3. Cutting tools
  4. Extrusion dies
  5. Heading dies
  6. Plugs
  7. Mandrels

The material of the tools also matters. In high temperatures, tool life may diminish and a lubricant that extends tool life improves performance and reduce costs. Tooling can be made of the following materials:

  1. Steel
  2. Carbide
  3. Diamond (synthetic or natural)

Subsequent Processes and Applications

Once a workpiece has completed the metal working process, most likely it still has to go through more manufacturing processes. Some of these include: annealing, cleaning, painting, and assembly into the final product. Cleaning the workpiece is import for final assembly as you want to avoid rust and corrosion. Drawing fluids that are emulsifiable are easier to clean and are preferred by some manufacturers. The cleaning process used also matters. Whether you use a dip tank, spray washer, or vapor degreaser, selecting a fluid that can wash away while also reducing rust and corrosion will be dependent on the cleaning process. Many fluid manufacturers, such as Twin Specialties, supply cleaners that are developed with their drawing fluids in mind.

Economic Considerations

With limited budgets, manufacturers must be pragmatic in selecting a fluid. Opting for a less expensive product may have hidden costs that are not realized at time of purchase. Lower quality fluids may reduce tool life and the fluid itself may need to be changed more frequently. These costs can add up and may not be realized until the job is completed. If your budget allows for it, opting for a synthetic fluid may prove to be a smart choice. Even though lubricants do not make up most of the budget, selecting the right lubricant can create tremendous cost savings on other parts of the income statement.

Takeaways

Each manufacturer has unique conditions and budgets; thus, no lubricant can be a one-size-fits-all product. Analyzing your metal workpieces, operations, tooling, cleaning and assembly processes, and budget will provide clarity. That clarity can aid lubricant selection and allow you to focus more on your manufacturing.

Working with manufacturers and distributors to determine the proper lubricant is the best strategy to maximize efficiency and boost the bottom line. Twin Specialties can analyze your processes and budget considerations to find the optimal lubricant.

How to Get Rid of Microbes in Your Sump

Bacteria or Fungus in the Machine Sump

At some point, your metalworking fluid will go bad. Hopefully, in most cases it has ran through its effective life and can safely be removed or recharged with a fresh batch. However, sometimes a fluid’s life will be cut short due to unforeseen circumstances. This may involve machine leaks, breakdowns, or outside contamination. In some instances, your fluid and machine may be filled with bacteria or fungus. When this happens, it is imperative to stop operations and remove all fluid from the sump to prevent any further issues.

If there is any remaining contaminated fluid still in the machine, it will decrease the life and effectiveness of the new charge as the fungus and bacteria will continue to thrive in the existing fluid. It is best to also run a cleaner through the machine to help clean hard-to-reach areas such as pumps and hoses. In addition to cleaning out the contaminated fluid, the cleaner removes process oils, gummy deposits or oil, grease, swarf and other outside contaminants. Monroe Fluid Technology’s Astro-Clean A contains special additives designed to render the machine neutral of bacteria and fungus.

Bacteria and fungi grow in the presence of increased surface area in a fluid. As more bacteria and fungus are in the machine, the faster the growth. This exponential growth problem can wreak havoc on your machine and lead to serious problems. That is why it is important to be proactive in managing your fluid. This will lead to reduced down time and increased performance. The main component of fluid maintenance is following the manufacturers recommended concentration and regularly checking the fluid and adding any additives necessary to maintain the highest performance.

Biocides and Metalworking Fluid Additives

One key additive is biocide. Biocides are designed to kill bacteria, fungus, and other living microbes that will damage the fluid. These additives can simply be added to any sump or central system. Grotan is designed specifically for metalworking fluids to extend fluid life. Grotan is meant to be added at 0.15% (1500 ppm) and will fight bacteria and fungus. Many products are formulated with a biocide, like Grotan, to help protect machinery, tools, and work pieces.

Metalworking fluids with biocides are constructed with recommended concentrations in mind. This matters when a machine may be running “lean” on a fluid. If the manufacturer calls for 4%, but the machine is running at 2%, the machine only has half as much additives as needed. There must be a minimum level of biocide present in a solution in order for it to be effective. If there is not enough biocide, the bacteria will not disappear and slowly but surely repopulate. Therefore, it is imperative to follow manufacturer guidelines to enough there is enough biocide and other additives in your solution.

To ensure proper performance, it is important to regularly check the concentration of the solution to ensure the product performs as expected. Using refractometers to measure the Brix/concentration is crucial in maintaining an aqueous solution. This allows users to see the exact concentration and make adjustments as necessary. It is recommended to record the concentration level daily. Due to water evaporation, it is important to add concentrate to your sump to maintain recommended concentration. Never add just water or concentrate, it is recommended to add both to maintain the sump for longer tool life. Mixers are recommended to ensure consistent refills and measurements.

Cleaning Best Practices

It is also important to hand-wash/hand-wipe reachable areas of the machine to remove any solids from the sump. If these solids are not removed, it can result in continued growth of fungus or bacteria. Fungus typically grows by attaching itself to a solid in the sump or system. Theses solids may be outside contamination or smaller clusters of fungus. Therefore, it is crucial to remove solids and deposits before AND after running a cleaning solution through your machine.

If you are unable to dedicate a time to clean and service the machine, the cleaner can be added to the metalworking fluid solution at a concentration of 1-3%. This allows for cleaning while machining parts. Build-up will release from the machine as production continues. It is important to remove these residues and solids after the system is drained. As new fluid flows through the machine after recharging, some deposits may dislodge and appear in the sump. This is normal and should occur during the first week of a new charge.

Contamination that Grows Bacteria and Fungus

In addition to using a cleaner after draining the sump, it is important to follow fluid maintenance best practices. For example, it is recommended to have some method of skimming tramp oil. This can be done by hand or by having an oil skimmer installed in your tank or sump. When tramp oil gets into the mixture, contaminants from the oil can become “food” for bacteria. The tramp oil will also sit on the top of the sump and provide a “seal” which will allow anaerobic bacteria to thrive and multiply. This results in rancidity, which can create less than ideal work environments.

Sometimes outside contaminants can get into the sump and can create surface areas for bacteria and fungus to attach themselves and grow. This build-up can lead to dead zones in the machine where fluid flow is limited or halted completely. It is important to have mechanisms in place to regularly remove solids from the sump. Some examples of tools include: magnetic wheels, conveyors, and indexable filters. In the case of fungi, the fungal mass will remain in the system since it will not disintegrate in the fluid. Therefore, it is important to remove any fungal mass to prevent future growth. Having these items in the machine allow for solid removal and higher performing fluids.

Twin Specialties Can Help

If your sump is filled with harmful microbes, we are here to help. Twin Specialties has a variety of products and resources available to help get rid of microbes. We offer cleaners and biocides that can be incorporated into your sump and metalworking fluids. Contact us for a coolant management guide, a site visit, or fluid testing. We can discuss how to fix your sump and establish practices to uphold the integrity of your metalworking fluids.