By Ember Sullivan
HOUGHTON--Researchers at Michigan Tech are seeking ways to solve air quality problems caused by potentially harmful airborne particles in machining processes.
In recent years, leading manufacturing industries have become concerned with the wastes produced by their manufacturing operations, according to Dr. John Sutherland of MTU's Department of Mechanical Engineering-Engineering Mechanics. One specific matter is the airborne particles produced by machining processes that degrade the air quality in their employee's working environments. For several years, General Motors and Ford Motor Company have recognized this problem associated with cutting fluid usage in machining processes.
"A machining process, such as drilling or milling, changes the shape of specific parts," Sutherland explained. "Often, during these machining processes, cutting fluids are added to the machine to provide lubrication--make things slide easier--and help draw out the heat. The cutting fluids, paired with the hot temperatures of the active machines, create a mist that is released into the air."
Sutherland explained that the mist created by the cutting fluids used in machining processes may cause health problems for those who inhale it. Testing the air quality in such environments is important, in order to determine the severity of the problem, and to know how to correct it.
"The size of the drops of mist (from the cutting fluids) is a factor in determining its harmfulness," said Sutherland. "Larger drops, being heavier, tend to fall to the ground faster; therefore, they are less likely to be inhaled. The smaller drops are more harmful to the employees because they float in the air longer, making them easier to inhale."
When these droplets are taken into the lungs, they are deposited in the tiny alveoli; long-term health effects can be caused by build-up of chemicals. Numerous respiratory diseases such as bronchitis or asthma could develop, according to Sutherland. Scientists suspect that extended exposure could allow lung cancer to develop.
Many would say that eliminating cutting fluids from the machining processes is the solution to the air quality problem, said Sutherland, "It is a more complicated issue than that."
"Cutting fluids are believed to provide a number of benefits in machining, so they are not easily done away with," he said. "They help in the process by reducing the forces, extending the life of cutting tools, and reducing the amount of thermal distortion."
Not only do cutting fluids provide some benefits, but their use solves a problem associated with dry machining--the creation of airborne dust particles. The particles of dust are very small, and can be inhaled just as easily, if not easier, than the small droplets of mist produced by cutting fluids. Therefore, machining processes, with or without cutting fluids, may pose a health problem for those in machining environments.
"Our goal is to try to find solutions to these air quality problems," said Sutherland.
The funding for the air quality research is provided by the National Science Foundation (NSF) as a part of Sutherland's Presidential Early Career Award for Science and Engineering. The grant also includes a supplement to support undergraduate research on the project.
"This is a good way to entice students to go on to graduate school," said Sutherland. "I want to encourage students to separate themselves from the rest of the pack."
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11/10/1999 MTN199