Occupational Health & Safety

Seed-Based Metalworking Fluid

This green product cuts waste disposal costs and reduces employees' exposure to respirable mists or dermatitis from skin contact.

DURING the past 45 years, the metalworking production capacity of the United States has increased dramatically because of innovative changes in equipment technology. Machining, tools, and measuring instrumentation deliver lower tolerances that create finer lines of acceptance or rejection between profit and waste. Microprocessors control operations at higher speeds and with greater precision. Each factor increases the need for lubricant technology, which in turn has increased chemical exposure levels to the employee and environment.

Metalworking fluids represent the critical interface between the tool and part being formed. The Industrial Revolution never would have occurred without them. Until recently, these products have changed in chemical composition to successfully meet the needs of the job, rather than evolve in content to meet the need for employee safety, the work in progress, and the environment. According to NIOSH, OSHA, and EPA, results from increased studies continue to document adverse health and environmental impacts from mineral- and synthetic-based metalworking fluids.

Seed-based oils (soy) represent a renewable resource innovation in metalworking fluid technology that delivers solutions to competitive disadvantages. Let's examine and measure the value added for production and the EHS issues surrounding them.

It's no secret machining operations such as grinding, stamping, milling, drilling, or broaching are built around feeds and speeds, extended tool life, decreased downtime, enhanced parts finish, and waste minimization. Many studies have shown the quickest and most cost-effective way to enhance production beyond the machine design can be through a lubricant/coolant that allows the machine and tool to work faster and with less wear from friction or chemical decomposition.

NIOSH indicates past and current use of mineral-based lubricants and coolants (straight, synthetic, semi-synthetic) are producing potent side effects to the operators and adjacent workers of metal forming equipment. The exact composition(s) of each product's chemical additives responsible for increasing the health risk(s) to employees is uncertain and is still being evaluated. These additives are needed to control biologic growth, enhance fluid stability, impede corrosion, extend tool life, and maximize heat resistance. OSHA and NIOSH have published studies evaluating these products and have outlined their findings and recommended controls to reduce the toxic exposure to workers who breathe aerosols or come into contact with MWFs.

Seed-based oils represent an evolution in technology that matches the investments of today's high-speed metal working machinery. They have emerged as a renewable resource that contributes to the continual improvement process found in manufacturing. In addition to being a green product, this fluid provides bioengineering enhancements that improve stability without additives and have a natural resistance to bacteria growth. They can contain natural elements that provide superior barrier protection between the tool and part, enhancing feeds and speeds, tool life, and part finish. Safer byproducts during production reduce employee exposure to respirable mists or dermatitis from skin contact. They also can provide easier and less expensive options for waste disposal.

Optimally, a metalworking fluid must create and maintain a barrier between the work piece and tool that evenly distributes the energy required during forming or cutting a specific grade of metal. To maintain effectiveness as a core lubricant/cutting oil, energy in the form of heat (650C to 950C) is transferred to chips via a secondary level, namely the coolant fluid. If engineered smartly, this combination of lubricant and coolant minimizes tool wear and produces a smooth finish on the part. This ultimately enhances efficiency in cleaning and finishing operations. The higher the tool efficiency, the faster the feed and speed. This increased production results in lowered costs per part and an added bonus of lowering the energy consumption required to produce a part. Anyone who is working toward EPA's Energy Star status will appreciate this added cost savings and notable reduction of greenhouse gas emissions. (An often-overlooked benefit is efficiency enhancements that are experienced with a new product. EPA's Energy Star programs promote the reduction of greenhouse gas emissions, which are directly related to a facility's ability to lower energy consumption over time. This provides direct cost savings, which in turn reduces the overall cost of producing a part.)

Metalworking fluids focus on two basic processes, metal deformation and metal removal or cutting. Today's market offers many suitable products that are mineral, synthetic, or most recently, made from seed oil. Mineral and synthetic oils are available in numerous compositions with various additives specifically designed to stabilize the fluid to meet a specific production need. Today's seed oil technology has evolved through bioengineering, so your choice of MWF doesn't have to change with each process. Also, seed-based products require minimal to no chemical additives, lessening their restrictions in the production and waste cycles.

To examine and measure the added value of seed-based MWF, it is helpful to review what's needed to validate that a lubricant delivers value added.

Promoting Safer Working Conditions
The first item to consider whenever bringing a new chemical into the workplace is employee safety. Most companies have a chemical approval process (or should have one!) that evaluates all incoming chemicals for hazards based on the latest available Material Safety Data Sheet.

The HMIS labeling should be reviewed as part of the OSHA compliance initiative with the Personal Protective Equipment Standard (1910.132-.138), Hazard Communication Standard (1910.1200), and Respiratory Protection Program (1910.134). Medical monitoring should be discussed and considered with a medical professional. Companies always should seek alternatives that eliminate or reduce the health risks to employees. Because MWFs are a critical component to machining, this process cannot be eliminated, but exposure can be significantly reduced through substitution with a less hazardous alternative. Seed-based products can have a significant advantage here.

In 1998, the National Institute for Occupational Safety & Health published a guideline, "What you need to know about Occupational Exposure to Metal Working Fluids." Next came OSHA's publication "Metal Working Fluid Safety & Health Best Practices Manual." Both of these were made available to the public as a result of studies made by NIOSH to evaluate the elevated risks of cancer to employees working in direct contact with respirable mineral oil mists.

Because of the elevated cancer risk, OSHA's Permissible Exposure Limit for workers over an 8-hour time exposure to mineral oil mist at 5 mg/m3 is being evaluated. There is strong consideration toward reducing the PEL to .5 mg/m3. The controls required to measure and maintain this proposed standard add to the cost of using mineral-based lubricants. In contrast, with the introduction of vegetable oil (seed-based/soy), the respirable limit for this exposure has remained at 15 mg/m3.

When comparing the OSHA and NIOSH studies, the MSDS of a seed-based technology has emerged as the employer's safest choice.

Environmental Benefits
EPA regulates the disposal of metalworking fluid waste through the Resource Conservation and Recovery Act (RCRA). By EPA's definition, waste fluids are identified as "specific" or "non-specific" (ex. chlorinated oils). Vegetable oils at the source are non-toxic and contain limited if any additives.

Treatment and disposal options available to industry today are contract hauling, chemical treatment, ultra filtration, incineration, and evaporation. The preferred method of disposal for mineral, synthetic, or vegetable oil is incineration. The cost of hauling and disposing of non-toxic vegetable oil can be similar to mineral or synthetic (without a high chlorine content) becaue of the cross-contamination that occurs during the production process. The cost of disposing these oils is much less than for metalworking fluids that contain chlorine greater than 1,000 PPM. EPA has designated these solvents as halogenated oily wastes that must be disposed of as hazardous waste in a designated treatment/storage/disposal site (T/S/D).

Metalworking Fluid Management
Any company that makes extensive use of metalworking fluids should have a Coolant Committee that oversees the metalworking fluid management program. This committee should consist of engineering, safety, environment, R&D, laboratory, production, and waste treatment departments. In-plant testing should evaluate performance.

The cost of using any product should be balanced with the cost of creating a safe workplace and environment, from a social responsibility point of view. Society of Manufacturing Engineers literature advises that one fluid should be established as the core lubricant/coolant. This provides less error during consistent monitoring and managing of hazards and cost. As an added bonus, documentation of these committee decisions and actions could aid those companies that form a supply chain for other corporations seeking to integrate their environmental goals into their suppliers.

The key to speeding production cycles is maintaining efficiencies during all phases of the production cycle. Using a lubricant that produces enhanced parts finish and is easy to clean will minimize the time and cost required for finishing. Use of a process mapping evaluation may indicate a significant reduction in the finishing process and time required for delivery based on the quality of the parts being produced with a high-quality lubricant. This is another example of an opportunity to reduce energy consumption and cost.

How should you compare to ensure what you have chosen is right for you? You should consider employee safety and environmental concerns, performance, and cost. EHS considerations always should have priority over decisions involving chemical use. Lab testing and a trial evaluation are key considerations for the Coolant Committee's oversight of the metalworking fluid management program. Evaluation templates (Figures 1 and 2) have been developed by manufacturing engineers and EHS professionals, and these produce EHS, financial, and production benchmarks to justify decisions. Figure 1 calculates the actual cost of a coolant during the production cycle. Figure 2 balances the cost of the coolant with the overall cost of producing a part with high-end feed and speed enhancements. This will aid operations managers in determining the overall savings on a cost-per-part basis.

Star Qualities
Three qualities--high-end speed & feed, maximum tool life, and decreased downtime--make up the dream team elements of high-production, low-cost machinery. A Connecticut company, Pantera, Inc., has developed seed-based oil mixed with nano-sized particles of molybdenum that delivers all three elements. This green product caught the attention of U.S. Rep. Nancy L. Johnson, R-Conn., who met with Pantera and Sustainable Products, Inc. representatives and began supporting the use of this renewable resource. Johnson views this green industry as one opportunity that can help American businesses improve employee safety and protect the environment while lowering overhead and increasing the production capacity needed to maintain an edge on foreign competitors.

How to Compare the Cost of Your Coolants
The second step you should evaluate is the total cost involved with using a specific type of lubricant. Here are the categories suggested by the Society of Manufacturing Engineers. This example, based on a 10,000-gallon transfer* (see Figure 1 below), is shown for illustrative purposes only to demonstrate the elements required with evaluating a lubricant. It allows the reader to see how each one affects the bottom-line cost to an organization over time.

Figure 1: Coolant Cost Comparison Worksheet

Evaluation Criteria

Avg. Cost Mineral

Avg. Cost Synthetic

Avg. Cost Vegetable

Purchase price/gal.

$12

$17

$24

Recommended dilution

1:20 (5%)

1:26 (3.8%)

1:20 (5%)

Cost/mixed gal.

$0.60

$0.65

$1.20

Cost to fill system

$6,000

$6,500

$12,000

Expected fluid life

6 months

12 months

12 months

Replenishment ratio

1:25 (4%)

1:83 (1.2%)

1:83 (1.2%)

Replenishment cost/day

$240

$78

$144

Waste treatment/gal/yr.

20,000

10,000

10,000


Annual Cost Summary

Fill system

$6,000

$6,500

$12,000

Replenishment (250 days/yr.)

$60,000

$19,500

$36,000

Labor

$2,100

$1,050

$1,050

Waste treatment

$23,700

$11,800

$11,800

Total annual cost

$91,800

$38,850

$60,850

* Template outline from Society of Manufacturing Engineers/costs are estimates for comparison purposes only.

How to Compare Your Manufacturing Process Improvements
The third step to consider is the performance of the product based on output. Higher feeds and speeds coupled with reduced finishing requirements results in more product produced in less time, at less cost. Here are items to consider and a sample spreadsheet that can be used for evaluation purposes.

Figure 2: Cost Comparison Worksheet Based on High-End Speeds and Feeds

Evaluation Criteria

Mineral Oil

Synthetic Oil

Vegetable Oil

a. Total tooling cost




b. Total labor cost




c. Total lubricating cost




d. Total cleaning cost




e. Waste disposal cost




f. Energy consumption




g. Total production cost

a + b + c + d + e + f

a + b + c + d + e + f

a + b + c + d + e + f

h. Total # parts produced




Total Cost/Part

g ÷ h

g ÷ h

g ÷ h

The Value of Purchasing a Green Solution
While examining and measuring the value added of purchasing a green product, seed oil has emerged as a renewable resource technology that can meet the challenges presented in today's manufacturing environment. When considering key MWF concerns, this innovation can contribute as a component to the continual improvement process with employee safety, the environment, reduced energy consumption (EPA Energy Star), and enhanced production measures for present and future cost savings that affect the bottom line.

Today's seed-based oils contain bioengineering enhancements that improve stability and have a natural resistance to bacteria growth. They contain natural additives that provide superior barrier protection between the tool and part, enhancing feed and speed, tool life, and part finish. Safer byproducts are produced, enhancing employee safety because there is reduced exposure to toxic respirable mists or from skin contact. They also provide easier options for waste disposal and contain no chemical additives, eliminating employee exposure and an additional waste stream into the environment.

Most importantly, this new innovation represents a product that can significantly reduce the current questions of which "combination of additives" in the mainstream offerings of mineral/synthetic-based oils contribute to the NIOSH/OSHA carcinogen potential evaluations. A significant value added with the purchase of a green solution.

Bibliography
1. Improving Production with Coolants and Lubricants, Society of Mfg. Engineers, "Can Synthetic Lubes overcome friction in the marketplace?" J. Obrzut, 1982.
2. The Register Citizen, "Environment Friendly Lube Created," Torrington, Conn., May 20, 2003.
3. McGraw-Hill, Machining and Metalworking Handbook, 2nd Edition, R. Walsh, 1998.
4. Metalworking Fluids, J.P. Byers, Editor, Dekker Books, 1994.
5. What You Need to Know About Occupational Exposure to Metalworking Fluid, NIOSH, 1998.
6. MetalWorking Fluid Safety & Health Best Practices Manual, OSHA, 1999.
7. MetalWorking Fluid, Mineral Oil Carcinogen Study, NIOSH, 2001.
8. Encyclopedia of Occupational Health & Safety, Fourth Edition, Int'l Labour Office, Geneva, 1998.
9. Soy Lubricants, Technical Background, United Soy Bean Organization, 2002.
10. Using Bio-based lubricants at Hydroelectric Facilities, EPA Study, 2002.
11. Soy based Metalworking Fluids Deliver Superior Performance, USBO, 2001.

This article originally appeared in the January 2004 issue of Occupational Health & Safety.

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