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Stamping (also known as pressing) includes a variety of sheet-metal forming manufacturing processes, such as punching using a machine press or stamping press, blanking, embossing, bending, flanging, and coining. This could be a single stage operation where every stroke of the press produces the desired form on the sheet metal part, or could occur through a series of stages. The process is usually carried out on sheet metal, but can also be used on other materials, such as polystyrene.
- Repoussé and chasing (embossing)
- Progressive stamping
Synthetic stamping lubricant
Metal stamping is the process of placing flat sheet metal in either blank or coil form into a stamping press where a tool and die surface forms the metal into a net shape. That tribology process generates friction which requires the use of a lubricant to protect the tool and die surface from scratching or galling. The lubricant also protects the sheet metal and finished part from the same surface abrasion as well as facilitate elastic material flow preventing rips, tears or wrinkles. There are a variety of lubricants available for this task. They include plant and mineral oil based, animal fat or lard based, graphite based, soap and acrylic based dry films. The newest technology in the industry is polymer based synthetic lubricants also known as oil-free lubricants or non-oil lubricants. The term "Water-Based" lubricant refers to the larger category that also includes more traditional oil and fat based compounds.
History and development
The first synthetic stamping product used for heavy stamping was invented in 1982 by Mr. Art Dampts while employed as Director of Research at Evanston Illinois based IRMCO Mr. Dampts was also the first to coin the term “non-oil fluid” as a distinction from other types of legacy lubricants. IRMCO Non-Oil Fluids were unique for the time. While in the early 1980’s synthetics were not new to the cutting fluid industry, stamping lubricants were typically a heavy oil or a pigmented loose fatty emulsion. The lubricant choices for metal stamping companies had gone relatively unchanged since the 1930’s when Henry Ford approached George Pillsbury, founder of Pillsbury Chemical and Oil to formulate a stamping/drawing compound for his River Rouge Plant. The Pillsbury Drawco product was a white, pigmented paste product formulated with calcium and animal fat. This kind of product chemistry became a standard for the industry and is still used in many automotive plants today. Mr. Dampts and IRMCO were the first to use polymer based ingredients. Synthetic Stamping Lubricants should not be confused with synthetic oil—chemically modified petroleum distillates commonly used as motor oils and other maintenance oils. Synthetic Stamping Lubricants are water-based solutions containing anywhere from 35% to 80% water in their concentrate form. Synthetic Stamping Lubricants are typically a complicated blend of poly glycol and/or ester based polymers. Some pseudo synthetics or “look a likes” are soap-based products utilizing plant oils or other fatty materials. The term “Synthetic” has become overly broad in recent years creating some market confusion. Mr Dampts impetus to invent the synthetic stamping lubricant category was driven by the remnants of the 1973 Arab Oil Embargo 1973 oil crisis and the very real 1979 energy crisis. Domestic oil was in short supply and prices were rising. Art Dampts’ innovative use of polymers made water behave more like oil in the metal stamping process. His synthetics were more viscous and displayed an ability to stay in place in some of the most severe metal stamping and drawing operations. Using water instead of oil as the base of the product created less dependence on foreign oil supplies and better price and supply stability.
One of the first industries to take advantage of and embrace the new synthetics were lawn and garden manufacturers such as Ariens, John Deere Tractor, Murray (bicycles) in Tennessss and AYP (now Husqvarna AB). Companies making lawn mower decks and tractor fenders struggled with using heavy oil and its effect on downstream costs such as parts cleaning, welding and paint quality. Automotive manufacturers took a little longer to consider the new technology. Nissan Motor Company was the first OEM to accept a synthetic when they approved IRMCO Non-Oil Fluids 146-000 in 1989. North American-based OEMs did not approve a synthetic until Ford Motor Company approved one in 2000. Most European OEM Automakers have not made the decision to approve oil free or synthetic stamping lubricants.
After IRMCO’s first synthetic introduction in 1982, the company was alone in the market for over 5 years. As with anything new, the metal stamping industry was slow to change. Oil or animal fat products still dominated the market for many years until synthetics were able to prove themselves in the marketplace. It was soon discovered that the right synthetic formulation was more environmentally friendly when or if it reached the environment, essentially starting the “green” movement in metal stamping plants. When users were able to remove oil from their operations by using a synthetic, they were able to take advantage of a cleaner plant, easier product recycling or disposal and less energy and chemicals needed to clean and prepare metal parts for e-coating and painting. Oil and animal fat formulations also have a much more toxic fish kill or LC50 rating compared to properly formulated synthetics.
With the introduction of Advanced High Strength Steel (AHSS) also referred to as ultra-high-strength steel (UHSS) the frictional demand on metal stamping and drawing dies has driven the need for a more modern water-based lubricants. The AHSS properties that exhibit themselves in the metalforming process are the same as those seen when the metal is used in a vehicle and that vehicle crashes. AHSS is engineered to be lighter and stronger, however when it is “worked” in a tool and die, the metal work-hardens (Work hardening) and requires more energy to form into a net shape. The increase in work hardening and required forming force/energy combine to create a more demanding temperature range and higher demand for lubrication. IRMCO research engineers discovered that proprietary polymer synthetics are heat activated and work better the harder they are pushed. With the increase in frictional temperatures, traditional oil and fat based formulations will fail sooner.
Stamping simulation is a technology that calculates the process of sheet metal stamping, predicting common defects such as splits, wrinkles, springback and material thinning. Also known as forming simulation, the technology is a specific application of non-linear finite element analysis. The technology has many benefits in the manufacturing industry, especially the automotive industry, where lead time to market, cost and lean manufacturing are critical to the success of a company.
Recent research by the Aberdeen research company (October 2006) found that the most effective manufacturers spend more time simulating upfront[clarification needed] and reap the rewards towards the end of their projects.
Stamping simulation is used when a sheet metal part designer or toolmaker desires to assess the likelihood of successfully manufacturing a sheet metal part, without the expense of making a physical tool. Stamping simulation allows any sheet metal part forming process to be simulated in the virtual environment of a PC for a fraction of the expense of a physical tryout.
Results from a stamping simulation allow sheet metal part designers to assess alternative designs very quickly to optimize their part for low cost manufacture.
Industry Specific Processes
Metal stamping can be applied to a variety of materials based on their unique metalworking qualities for a number of applications across a wide range of industries. Metal Stamping may require the forming and processing of base common metals to rare alloys for their application specific advantages. Some industries require the electrical or thermal conductivity of beryllium copper in areas such as aerospace, electrical, and the defense industry or the high strength application of steel and its many alloys for the automotive industry. Industries Metal Stamping is used for:
- Circle grid analysis
- Forming limit diagram
- Four-slide machine, a combination stamping, bending, and punching machine
- Shearing (manufacturing)
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