AN EXPERIMENTAL INVESTIGATION INTO FACTORS AFFECTING THE BRAZE STRENGTH OF CBN CUTTING TOOLS

摘要

Many manufacturers are gradually moving away from high speed steel and carbide cutting tools in favor of Polycrystalline Diamond and Cubic Boron Nitride tools. These tools, on average, tend to cost more; however, they can increase productivity and lower unit cost per part because of their higher cutting speeds and improved tool life. Additionally, these tools are an attractive alternative to conventional cutting tools due the better surface finish and high tolerance to heat; therefore, in most cases, eliminating the need for coolants. However, erratic and unexplained tool failure with CBN grooving tools have been encountered. In the particular application investigated, the problem was thought to arise from the tool manufacturing process rather than the tool design. An experimental design was conducted to analyze the tool fabrication process and uncover factors effecting the tool strength. Five such factors were identified and an "Analysis of Variance" study based on a fixed-effect model was carried out to determine their actual effect. It was found that the tool failure was due to inadequate braze temperature.