Volume 13, Number 2

ENVIRONMENTALLY CONSCIOUS

DESIGN AND MANUFACTURING RESEARCH

MOHSEN SHAHINPOOR

Editor-In-Chief

Albuquerque, New Mexico

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Environmental and occupational safety regulations continuously urge manufacturers to reduce manufacturing dust and other contaminates such as those generated by cutting fluid because they represent an industrial hazard. Most machining processes whether dry, semi-dry or wet produce dust particles, which remain suspended in the air long enough to be inhaled by the workers. These particles can lead to serious health problems. To be able to perform clean and safe machining operations, there is a need to develop a technique, which would help in identifying the different parameters and conditions that influence the production of metallic dust during machining.

The goal of this work is thus to seek the fundamental causes of the production of dust during dry machining to be able to control and limit it. To achieve this objective, light materials (aluminum alloys and magnesium alloys) and brass are drilled at different machining conditions and their effect on fine dust generation is studied. This study enabled us to identify several mechanisms by which the dust is formed during machining and to propose methods to perform a clean machining process and thus limit at the source the generation of such dust. This first part of a two-part paper details the influence of the drilling process parameters and work piece materials on dust emissions. It is found that there are two ranges of cutting speeds where the dust production is minimum. The amplitude and the location of these ranges are function of the nature of the work piece materials. The chip formation is used to explain the results. Part II details the influence of the machining strategies as well as the drill geometry and condition on dust emissions and provides practical strategies to limit the dust generation.

This is a second part of a two-part paper on clean machining. The first section introduced the topic and presented the experimental study related to the influence of process parameters, work piece materials characteristics and chip formation on dust emissions. In this part II the results presented in part I are further investigated and are used to design machining strategies which limit the dust generation during dry machining of aluminum alloys, magnesium alloys and brass. Machining strategies commonly used in industry as well as work piece initial preparation, tool condition and geometry are also investigated and their effect on dust emission evaluated. It is found that by using appropriate machining strategies the dust emission can be reduced by at least a factor of 10 depending upon the strategy and the nature of work piece materials used. It is also found that there are significant correlations between the tangential forces, the torque and the amplitude of the vibrations and the dust emission and that there is no direct correlation between the thrust force and the dust emission.