Milling cutters come in various types and shapes, but they can be broadly categorized into two forms: cylindrical milling cutters and face milling cutters. In essence, each tooth on a milling cutter can be thought of as a simple turning tool. With more teeth, an understanding of the milling cutter's geometric angle can be derived by analyzing just one tooth. Let's take a closer look at the geometric angle of a face milling cutter as an example. A tooth on a face milling cutter is akin to a miniature turning tool, and its geometric angle closely resembles that of an external turning tool. The base plane is the defining plane in this case. Consequently, each tooth on the face milling cutter possesses four fundamental angles: the rake angle, relief angle, main declination angle, and edge inclination angle. By examining these angles, we can gain insight into the milling cutter's geometry and performance.
The front angle, denoted as "γο", refers to the angle formed between the front plane and the base plane. This measurement is typically taken from an orthogonal plane, serving as an important aspect in determining the geometry of a given object.
The relief angle, denoted as αo, refers to the angle formed between the cutting plane and the back of the tool, when viewed in the orthogonal plane. This angle plays a critical role in determining the tool's ability to cut and its overall efficiency. When properly optimized, a suitable relief angle can significantly improve the tool's performance, making it more resistant to wear and increasing its cutting speed. It is, therefore, important to carefully consider the appropriate relief angle when designing and selecting tools for cutting operations.
The leading angle κr is the angle that exists between the main cutting plane and the working plane that is assumed to be used. This angle is measured in the base plane, and it plays a significant role in machining operations. Understanding the value of κr is crucial in ensuring that the cutting tool is applied at the correct angle, and this enhances the efficiency of the entire process. By adjusting κr, manufacturers can achieve precision cuts, and this can lead to the production of high-quality products. Therefore, taking into account the leading angle κr is essential for anyone involved in machining.
The edge inclination, also known as λs, is the angle formed between the base surface and the main cutting edge. This angle plays an important role in determining the cutting ability of the tool and must be carefully considered during the design process. By adjusting the edge inclination, manufacturers can improve the performance of their tools and achieve more precise cuts with less effort. With proper edge geometry, tools can cut through even the toughest materials with ease, making them an invaluable asset in many industries and applications.
Figure 4-2 displays the relevant angles of the face milling cutter in the main profile system. It's crucial to consider these angles during the design, manufacturing, and sharpening processes. Additionally, when working with the feed and back cutting tool profile system, it's necessary to also take into account the relevant angles, including the radial front angle γf and axial rake angle γp. These angles play a significant role in ensuring optimal performance and efficient cutting.