A Study of Cutting Fluids and Workpiece Surface Error in the Boring of Cast Aluminum Alloys
 
 

Douglas A. Cozzens | MS | 1995

ABSTRACT:

Escalating environmental regulations have forced industry to identify and reduce their significant waste streams. Spent cutting fluid is a significant waste stream in many manufacturing facilities today. Before a reduction or elimination can take place, the role of metalworking fluids must be established. Many functions of cutting fluids are identified including that of a coolant, lubricant, and chip transport medium.

In an effort to obseve cutting fluid effects in a production environment, a set of preliminary experiments was conducted. The influence of basic machining parameters including cutting fluid presence on performance measures such as surface finish, built-up edge formation, and machining forces was determined. The insignificant influence of the cutting fluid on the measures led to the investigation of the effect of cutting fluid on workpiece surface error.

Analytical modeling of the temprature field generated in a hollow cylindrical workpiece during a boring operation was conducted for both one and two-dimensional representations. Cutting fluid flow over the workpiece was modeled to determine an appropriate thermal convection coefficient. A model for the radial surface error was then developed using the temperature field model and thermal stress equations.

After calibration and validation of the workpiece temperature models, experimental models for the specific cutting energy and fraction of total power entering the workpiece were established. These experimental models were combined with the analytical models for the temperature field and surface error.A workpiece surface error model estimate with required inputs of only basic machining parameters resulted.

The surface error model estimates were determined for parameter combinations set by the experimental design. Results were statistically analyzed with normal probability plots. Significant machining parameter effects on the workpiece surface error due to thermal deformation were identified as cutting fluid presence, depth of cut, and feed.

A parametric study of the surface error model was also performed. The influence of the heat source intensity, feed rate, work material thermal diffusivity, and thermal convection coefficient on surface error was determined. A drastic increase in convection representative of cutting fluid application produced a minimal decrease in radial surface error.

If you have any comments or suggestions please e-mail jwsuther@mtu.edu.