Production Machining

MAY 2018

Production Machining - Your access to the precision machining industrial buyer.

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ese are products that have undergone rigorous testing to ensure the part experiences no harm, such as inner granular corrosion that could lead to part failure in the future. e nuclear industry often dictates the allowable levels of sulfur, chlorine and fluorine in honing oil used. Additional restrictions often apply regarding levels of arsenic, bismuth, antimony, silver, mercury, cadmium, gallium, indium, lead, tin or zinc beyond trace levels. Honing oil formulations are available to meet these requirements. ese are lubricants composed entirely of surface active lubricity agents formulated to a suitable viscosity. Because this type of product does not use additives, it is ideally suited for applications where additives are restricted. In job shop environments, where a variety of parts may be processed daily, MB-30 honing oil is known in the market as a general, all around honing oil. It can be used with most types of tooling, abrasives and workpiece materials and is typically non-toxic or irritating to the skin or eyes. Disposal is simplified because MB-30 does not contain chlorine or other materials that are restricted by the Environmental Protection Agency (EPA). e number of applications, materials and industries varies, as well as oils and lubricants available for the job. When trying to determine the best honing oil for an application, consult the honing experts first for advice in selecting the best, premium oil for an application. Material Type Honing oil must meet the lubrication demands of the material being honed. Difficult materials such as stainless steel require higher levels of surface active lubricity agents than easier materials such as cast iron, which is somewhat self- lubricating and gall resistant. Materials that form short, flakey chips such as carbide, glass or ceramic require less lubricity than those that form long, stringy chips such as aluminum. Consideration must be given to staining and discoloration of the parts when honing nonferrous metals. One remaining factor is the yield strength of the workpiece material. Strong materials such as tool steel will require higher honing forces on the abrasive to cut properly. ese higher loads place increased demands for lubrication from the honing oil. e type of abrasives being used is another consideration when selecting the right lubricant, whether conventional abrasives, metal bond superabrasives or plated diamond tools. Full service suppliers such as Sunnen Products have more than 20 different types of preformulated honing oils and lubricants that will match with its line of abrasive tools. Generally, the use of conventional abrasive with traditional honing mandrels (that have a guiding shoe surface) place the greatest demands on the honing oil. Requirements are diminished for honing units where only abrasive touches the bore with metal bond being more tolerant than conven- tional abrasive. Superabrasive plated tools appear to be most tolerant of honing oil performance. All metal bond and super- abrasive plated tools are often used with water-based coolant. Social Responsibility Chemistry plays a big role in not only how a lubricant performs, but also how it's handled. Like all cutting oils, depending on the chemical makeup, honing lubricants can be regulated by Occupational Safety and Health Administration (OSHA), the Department of Transportation (DOT) on how it's shipped, the U.S. Department of Agriculture (USDA) and the EPA on how it's used and disposed of. e chemical composition of each lubricant is also scrutinized by industry. e latest developments in honing oil technology can now deliver renewable/sustainable honing oil that is clean, green and 100 percent vegetable-based. ese oils are popular in Europe and growing in popularity in the U.S. Important Details Most honing machines use a filtration system to keep the oil clean. When petroleum-based honing oil is protected from pollution and properly filtered, "carry-off " becomes the biggest factor in honing oil usage. Carry-off is the amount of oil that sticks to the part during honing and is normally washed off the part after machining. Small parts have little carry-off, and a 55-gallon drum might last a year or more. Large parts with more surface area will contribute to more carry-off. Subsequently, the system's oil reservoir will need to be replenished more often. Oil viscosity plays a role as thicker oils will increase carry- off. Carefully matching the honing process requirements METALWORKING FLUIDS 34 PRODUCTION MACHINING :: MAY 2018

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