Converting your fluid systems to green

Environmental practices that can net black ink on the bottom line

The FABRICATOR December 2008
December 15, 2008
By: Milton Hoff

Metal forming, stamping, and washing fluids traditionally have been thought of as "necessary nuisances" to be used once and thrown away. That mindset is changing.Incorporating "green" or environmentally friendly fluids and fluid management systems can extend fluid life and minimize waste, providing valuable cost savings.

Manufacturing Fluids Image

Using a stable fluid and maintaining it at optimal performance for as long as possible will reduce the impact on the environment, preserve natural resources, and net black ink on your bottom line.

Metal forming, stamping, and washing fluids traditionally have been thought of as necessary nuisances to be used once and thrown away. That mindset is changing.

Incorporating green, or environmentally friendly, fluids and fluid management systems can extend fluid life and minimize waste, providing valuable cost savings. Metal forming, stamping, and washing fluids now are considered an important part of the production process—as important as tool life or health and safety issues—because they impact all areas of the operation.

As you consider implementing a fluid management and recycling program, take the time to examine all of your processes, and look at every stage where fluid touches metal. You may be able to make changes that reduce environmental impact and costs while increasing efficiencies.

Fluid Recycling Is Different

Recycling metalworking fluids differs from recycling other materials. Unlike recycling aluminum cans or newspapers, the intent of recycling fluid is not to take something that no longer has value, such as an empty can, and make it something of value. The goal is to utilize a stable fluid and maintain it at optimal performance for as long as possible, reducing the impact on the environment and preserving natural resources. Stamping fluids that will be recycled need formulations that are substantially more stable than those found in fluids used only once. The focus of recycling metal forming, stamping, and washing fluids is on managing the failure mechanisms inherent in working with these fluids.

Mixing and Concentration. Mixing is crucial to maintaining stability in forming, stamping, and washing fluids. For optimal performance and maximum life, concentrates should be mixed with the best possible water produced by deionization or reverse osmosis. Maintaining the right concentration ratio is essential to getting efficient and trouble-free results from water-miscible fluids. Appropriate mixing and concentration prolong sump life, tool life, and surface finish, as well as reduce fluid usage and disposal, which can have a significant impact on the environment and on the bottom line.

Machines and Washers. A key function of any recycling system is periodic cleaning of holding tanks and product-delivery plumbing. They should be kept clean as long as possible. Dirty machines and washers stress the entire system and spread bacterial and fungal growth. Most bacteria and fungi live in the matter found on the walls and bottoms of sumps and fluid-delivery plumbing.

Even the strongest biocides will penetrate only a short distance into these dense residues. To reduce the biological load in a machine tool sump, you must break up the muck to expose the bacteria to the biocide or totally remove it mechanically by machine cleaning. Running clean machines and washers increases tool and die life and reduces fluid usage, resulting in lower costs and impact on the environment.

Tramp Oil. Tramp oil contamination is a major contributor to fluid failure and can stress the system until the fluid no longer performs as desired. The adverse effects of tramp oil are proportional to the amount of tramp oil present and the fluids mixed with it. Problems are most pronounced with machines that leak the most oil as a percentage of the sump size or have fluids that tend to emulsify the oil in question. The effects are even worse in the central system, where reduced carryoff and continuous recirculation through powerful pumps keep the oil emulsified.

Preventing tramp oils from getting into the sump is ideal. Quickly and efficiently removing tramp oil that does leak into the sump lessens the stress on the system and yields bottom-line savings in costs and resources.

Proper Fluid Recycling Is Environmentally Friendly

Fluid recycling systems perform an essential function for the environment. Yet an effective process requires more than running dirty coolant through recycling equipment; it requires stable fluids, a well-executed fluid management plan, and a well-designed and properly maintained recycling system.

Three broad types of recycling systems are available:

  1. System dedicated to maintaining the fluid in a single machine sump, central system, or parts washer
  2. System that recycles batches of fluid that periodically are transported to the recycling system and then back to the machines as makeup
  3. A hybrid of the first two systems that handles one or more large systems and processes batches

Each of these system types uses different arrangements of basic functional components, including:

  • A system for cleaning the metalworking fluid tank on the machine and the removal of solids. This can be a sump sucker that pumps out the individual sump and has a filter basket for filtering solids or a conveyer and drag bars that clean a central system.
  • The feed tank, which can be a central system's dirty tank, the parts-washing system where the fluid is recycled internally to the operation, or a holding tank with a free-floating tramp oil removal device.
  • A tramp oil and microfine removal device.
  • A clean tank or makeup tank in which new or recycled product can be held and the concentration adjusted before returning it to the working system.
  • A source of good-quality water.
  • A method of returning the clean, recycled fluid to the metalworking fluid tank on the machine. Frequently pumps or sump suckers are used to return the fluid to the clean tank or central system.

Implementation: Where to Start?

The first step in implementing a fluid recycling system is to clearly define the problems you hope to solve. List the goals and objectives, and determine the extent to which your company is willing to make changes to its processes.

Reviewing every process and every place that fluids touch metal will provide you with a comprehensive overview. This offers an opportunity to evaluate how each process is working and identify areas for improvements and waste minimization.

Many fluid suppliers can provide expert advice and fluid management services to help re-engineer your existing processes and implement new recycling systems that will increase efficiencies, lessen environmental impact, and improve your bottom line.

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The FABRICATOR is North America's leading magazine for the metal forming and fabricating industry. The magazine delivers the news, technical articles, and case histories that enable fabricators to do their jobs more efficiently. The FABRICATOR has served the industry since 1971.

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