Excessive noise generation often occurs during the face-milling of thin-walled aluminum workpieces. It has been suggested that such noise can be reduced by utilizing milling cutters which employ non-uniform insert pitch.

This report presents the results of a test series undertaken to determine the noise reduction potential of four different non-uniform insert pitch cutters used to machine the engine mounting face of an aluminum transmission housing. The tests were performed using the actual high volume, transfer-line machinery.

It is shown that the use of non-uniform insert pitch does not necessarily reduce overall noise generation. There is, however, often a reduction in noisiness.

To better understand the structural response of the workpiece a complete modal analysis is performed. In addition, noise frequency response functions are generated and are shown to form a basis on which to predict the noise radiation characteristics of the workpiece.

A hybrid digital-analog computing system is developed and then used to simulate the workpiece response and to demonstrate the influence of various parameters such as forcing function definition, natural frequency, damping, and width of cut on system response.

A more realistic forcing function definition, than the often used force impulse model, is developed. It is subsequently shown that significant differences in workpiece response occur for excitations based on these two models. It is also demonstrated that variation in width of cut has a significant influence on the forcing function definition.

Several techniques for improving "quiet cutter" design strategies are illustrated. In particular, a technique of sectoring the workface into sections with constant "effective" width of cut is described. Such an approach permits the width of cut variation to be accounted for in a relatively simple manner. It is also shown that noise frequency response functions, when used in conjunction with a realistic model of insert engagement forces, allow prediction of workpiece noise emission characteristics as a function of cutter location.