A Closer Look at Forging Lubricants
Forward-thinking companies have found that value-added forging lubricants are easily cost justified when all component costs of forging manufacturing are examined. The challenge lies in the dialogue that occurs between forger and lubricant supplier in addressing the underlying goal: reduce the overall operating cost of producing parts.
Significant constraints are placed on forging companies by today’s end users. It is the acknowledgement of each forger’s unique – and constantly changing – method of manufacturing products that has led the Dylon team to develop more than 300 different forging compounds. We believe a clear understanding by forgers of lubricant technology available in the marketplace helps them select the best product for their process.
Oil-Based LubricantsThe Times They Are A-Changing. Years ago, there was a good chance that at least some, if not all, of the parts your forge shop produced incorporated an oil-based forging lubricant. In fact, numerous companies still use oil-based forging lubricants. The belief that these lubricants are on the low end of the technology spectrum is supported by the fact that some forgers have continued to use the same product for years. Unfortunately, companies employing this tactic are missing out on the advancements that have taken place in oil-based lubricants.
Even as recently as two years ago, many additives found in today’s oil-based forging lubricants were not used by the forging industry. Analysis of historical oil-based forging lubricants shows insufficient use of available anti-wear additives, friction modifiers, milled graphite and high molecular weight polymers (Figure 2). The incorporation of these raw materials has significantly enhanced oil-based forging operations. Hammer shops are capable of significantly reducing the number of strikes required to produce aerospace and heavy-industrial forgings. Forgers with mechanical presses have been able to consolidate the number of stages required to forge parts. Hydraulic presses are moving metal more easily than ever.
Advancements in petroleum and natural oil refinement have led to products with significantly less fire and smoke. Incorporation of newly developed additives and finely milled graphite reduces the amount of lubricant required in the process. This leads to less environmental impact on the forge shop. With the increased elemental constraints the aerospace industry places on forging lubricants, the days of “grandfathering in” oil-based shop lubricants are slowly going by the wayside. It is quite common that oil-based lubricants must meet complex customer specifications (as verified by independent labs) regarding their exact formulation, which may include up to 35 components. Nonetheless, forging-lubricant manufacturers have proactively been developing products to meet these demands.
Graphite LubricantsAre They Really Just Graphite and Water? The answer is no. The terms binders, wetting agents, adhesion promoters and friction modifiers are familiar to any forger that has read technical datasheets from lubricant suppliers. Numerous patents have been granted over the years identifying the use of borates, silicates, inorganic phosphates and clays as common additives found in forging lubricants. Although these components are still commonly found, a trend toward more organic-based additives has occurred. Bio-polymer and ester-based additives are increasingly common as forgers manufacture an expanding number of near-net parts. The move to higher-complexity forgings forces lubricant manufacturers to reformulate chemistries, placing emphasis on reducing lubricant buildup in the more detailed regions of the die.
The increased utilization of organic additives has led to the development of semi-synthetic formulations. These consist of significant amounts of organic soap complexes fortified with reduced levels of graphite. The soap complexes in semi-synthetic materials provide the binding and adhesion characteristics that inorganic materials provided in the past. Due to the lower thermal stability of soap complexes, significantly higher concentrations of additives can be incorporated without worries of aggressive buildup. Companies have found increasing performance with semi-synthetic materials compared to traditional graphite lubricants, specifically in the area of die life.
Additionally, not all graphite is created equally. The three types of graphite most frequently found in forging lubricants are natural flake, amorphous and synthetic graphite. Extensive literature is available that correlates optimum metal movement with natural-flake graphite. This is due to the plate-like structures that have developed over millions of years during the graphite-forming process. Amorphous graphite, another naturally occurring form, lacks the plate-like structures of flake graphite and contains high levels of impurities, commonly referred to as ash. Amorphous graphite is found in low-cost commodity lubricants where price is the driving force in lubricant selection. When the total cost of manufacturing is correctly calculated, seldom do amorphous-graphite products win out as the most appropriate choice.
Synthetic graphite is artificially created graphite that closely mimics natural graphite in shape and properties. The two most prominent characteristics of synthetic graphite are its purity and the ability to have its particle size significantly reduced. Dylon Industries is one of a few companies that possesses equipment to mechanically and chemically enhance graphite to the sub-micron level for use in forging lubricants.
Commonly known to the forging industry as “colloidal graphite,” this material has the characteristics of providing extreme detail, being effective on die surfaces in excess of 700˚F and being often found in progressive die flooded operations. Developments in particle-size reduction equipment over the years have made the process of developing “colloidal graphite” much more economical and thus more attractive to forgers. Recent research and development of the interfaces between sub-micron graphite edge sites, chemical additives and die surfaces has led to the development of more efficient graphite forging lubricants.
Synthetic LubricantsAre You Missing Out? It depends. If your goals are to clean up your forge shop, increase worker morale, provide a safer work environment and significantly reduce your manufactured cost of goods, the answer to the question is unequivocally “yes.” To obtain these benefits, however, working through a learning curve with your supplier and re-engineering some of your process is essential. In our company, sales engineers routinely do this with forgers.
Unlike graphite, which obtains its properties through solid particle lubrication, synthetic lubricants use a more complex mechanism to lubricate and protect dies in a sequential process (Figure 3). To take advantage of these materials, companies must often invest some effort into modifying their process. Normally, the issues are minor: different spray nozzles, adjustment to lube and air ratios, heating or cooling of a die, different concentrations, modified spray times, etc. If the forger’s mentality is “nothing can be changed in the process,” the likelihood of ever converting from graphite to a synthetic material is significantly reduced.
Upon installation of a synthetic lubricant, what are reasonable expectations? To start, a cleaner environment and improved worker morale will undoubtedly occur. The transformation of your facility from a dark, dirty manufacturing building to a clean modern-day production site will begin. Press operators and maintenance men will no longer leave work with graphite in their fingernails and the all-too-common black tissue after nose blowing. Slippery graphite-covered equipment that is often a safety hazard in forge shops will give way to clean, more user-friendly tools.
It is often hard to put a dollar value on cleanliness, although it can be done. Manufacturing costs are another story. Companies that have converted to synthetic lubricants, and have worked through the learning curve, normally see significantly increased die life when forging. Independent of the lubricant under evaluation, a synthetic material when optimized for a process can increase die life by 15% to 30%.
Another saving associated with synthetics is the reduction in waste-removal and waste-treatment costs. Modern synthetic lubricants are extremely soluble, allowing for the capturing and recycling of the forging lubricant. It is through the recycling of synthetic lubricants that companies can achieve significant cost reduction and obtain exponential bottom-line savings. The process is rather straightforward but site specific. The good news is that recycling often utilizes common equipment the forger already has at their disposal.
We advise our customers not to believe the myth that only simple parts can be manufactured with synthetic lubricants. Throughout the world, companies are forging a wide range of products with synthetics: pinions, crankshafts, gears, tulips, connecting rods, hubs, turbine blades, pipes and pistons to name a few examples. The truth is, conversion to synthetic lubricants is probably one of the most effective ways a company can alter its overall manufacturing cost.
Which Lubricant Should I Use?It is too bad this question doesn’t have a simple answer. Unfortunately, any easy answer only leads to more questions. Can I decrease my company’s insurance premiums by converting from an oil-based product to a water-based product? Do regulations exist that are moving me away from the use of oil altogether? Does an oil-based product exist that can help make those stubborn parts that give us so much trouble? Can we cost justify a value-added graphite versus a commodity offering and, more importantly, sell it throughout our organization? Do we have the company culture to support the conversion to a synthetic lubricant? Do we fully understand the costs associated with using a forging lubricant? Do we obtain adequate support from our supplier? Does our supplier help us develop continuous improvement projects?
These are just a sample of the questions that companies must ask themselves when choosing a forging lubricant. The best advice that can be given when selecting an appropriate product is, again, “don’t miss the forest for the trees.” Regardless of your personal views on forging lubricants, companies that understand the true costs associated with producing their parts realize forging lubricants can significantly affect their company’s bottom line. The industry is fortunate to have a number of reputable suppliers of forging lubricants who will be more than happy to help enhance your process.
Author Jeff Zdilla is Dylon’s director of operations; author David Poole is a development chemist. For additional information, please contact Jeff Zdilla at 216-651-1300, x127; e-mail: email@example.com
SIDEBAR: All About DylonDylon Industries, based in Cleveland, Ohio, has pioneered forging lubrication since its founding in 1967. The company’s lubricant-manufacturing facility serves forging companies throughout North America, South America, Europe and Asia, selling to more than 40 countries worldwide. Although a number of companies serve the industrial lubrication market, Dylon differentiates itself by focusing all its research and development efforts on the forging market, boasting the largest number of forging-lubricant scientists on staff in the U.S.
The company’s motto – Tomorrow’s Technology Today – has served as the basis for its operating philosophy through the years. The company’s expertise is the development of site-specific products, leading to maximum value for its customers. Forging lubricants are designed around specific parameters for an individual company’s facility and, in some instances, a single press. Dylon Lubricant Technologies – a division of Dylon Industries – has also developed a full line of maintenance products designed specifically for the forging industry.
From the day it opened its doors, Dylon made the strategic decision to focus its resources on forging lubricants and avoid the application equipment business. Given the large number of application suppliers in the industry, Dylon believes forgers achieve more value from a specialized lubricant supplier through a consultative approach to problem solving. Thus, an unbiased impartial opinion on lubrication best practices can be provided.
The company’s method of working with forging companies centers on a needs-assessment discovery approach. Rather than producing and distributing a list of stock products, Dylon sales engineers are often found learning about a company’s process and helping to identify its true problem areas. A full-service sales force is located throughout the world to help improve lubrication practices within the forging industry.