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Cool Info on Metalworking Fluids

 Ellen Kehoe








By Ellen Kehoe
Senior Editor

Chilled air dispersion can lessen the risks to workers of ingesting, inhaling or absorbing cutting fluids, as addressed by V.N. Malhotra, S. Arunachalam and P. Dewson (University of East London; Dagenham, Essex, England) in their 2005 paper reporting the novel experimental technique. The investigation applied a very small volume of water, containing 0.5% by weight soluble cutting oil, and high-velocity chilled air along the sides of the insert, aimed at the tool tip. No noticeable detriment to tool wear or chip production was seen.

The characterization of mesoscale grinding processes using compressed chilly air is described by Pil-Ho Lee and Sang Won Lee (Sungkyunkwan University; Suwon, Korea) in their 2010 North American Manufacturing Research Conference (NAMRC) paper. Grinding force, tool wear and surface roughness were measured and compared. The research demonstrated an increase in tool life and a decrease in machining forces in the mesoscale grinding process.
Nozzles aiming chilled air at the chip-tool interface (V. Malhotra et al., TP05PUB1).
A review of work to replace cutting fluids with gases in various machining processes is described in a 2008 paper by O. Çakir of Dicle University (Diyarbakir, Turkey). The literature summarized includes research using nitrogen, oxygen, carbon dioxide, carbon tetrachloride, argon and chlorine in various formulations as a coolants and lubricants.


Solid lubricants can have benefits as well. The efficiency of three popular choices—boric acid, molybdenum disulfide (MoS2) and graphite—is defined by cutting temperature during dry machining and surface roughness of the end product.

“From your everyday pencil to the lubrication of firearms,” graphite is relatively inexpensive, easy to obtain and has many more uses than in the past. Because graphite needs to absorb moisture from the air or an external process to be efficient, there can be build-up problems or lack of lubrication in certain area. Molybdenum disulfide does not require moisture to be used correctly. When sprayed on, it adheres to the surface of the metal being cut, thus being less wasteful and providing an even application. Further research has continued on this solid lubricant.

Boric acid is used in cosmetics, cements, enamels and skin ointments. Even though it is hazardous when mixed with other solutions for use in rat poison, boric acid is non-toxic and water soluble. It is easily removed from hard surfaces with water, making it desirable as a solid lubricant. Boric acid is sprayed on the same as MoS2 and also forms an even film.

Water-based grinding fluid shows cooler temperature distributions at the workpiece (S. Mihic et al., TP11PUB30).

A Necessary Tool

Cutting fluids, when properly handled, “are truly productivity tools. But if they are ignored, they can definitely become a nuisance.” Several overview papers provide a tutorial on fluids and coolants, including “A Primer on Metalworking Fluids,” “The Why of Metal Working Fluids” and “Cutting Fluids – Third Dimension in Metalworking.” The 46-page “Primer” highlights the wide range of available fluids “as a tool of production and applied to: (1) provide an adequate cooling action, (2) provide a tolerate tool and die life, (3) produce a satisfactory surface texture for the product and (4) maximize economical production parallel to an established quality standard.” Additionally covered are metal removing and metal working dynamics and cutting and grinding mechanics, as well as a discussion of the parameters in formulating metalworking fluids and the classes of metalworking lubricants.

SME Technical Papers

Close to 200 SME Technical Papers are filled with the what, why and how of selecting the best-suited metalworking fluid for each operation and using it under the proper conditions for worker and environmental safety.

In total, more than 16,000 papers and presentations make SME’s collection of manufacturing knowledge the largest of its kind. Find papers on best practices, advancements and industry trends. Add your insights to help others Learn More & Do More.

Published Date : 1/28/2015

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