Integrated optimization using mixture design to confirm the finishing of AISI P20 using different cutting strategies and ball nose end mills

The surface roughness of a milled surface is an important response parameter in finishing milling. The quality of injected products, such as cell phones, laptops, digital cameras greatly depends on the finishing of the molds. The Ra parameter is one of the most commonly used criteria to determine the quality of milled steel. In this study, experiments were carried out on work pieces of AISI P20 steel with 20 × 20 × 10 mm. Solid carbide tools with a diameter of 6 mm were used in the experimental tests. The input parameters were the radial depth of cut, feed rate, and contact angle. The contact angle varied using a special device to simulate the several inclinations in a free-form surface. The results showed that the milled surface is a three-dimensional geometry that is influenced by many parameters. The most important input parameter for the surface roughness, however, is the feed rate, and depending on the measuring direction; the feed rate can have a significant influence on the finishing.