In this video we take a closer look at turning. Depending on the surface produced and the feed direction, i.e. whether the workpiece is turned transversely or longitudinally to the axis of rotation, a distinction is made between longitudinal facing and transverse facing, as well as thread turning. A distinction can also be made between external turning and internal turning. Depending on the feed direction, the cutting edge has a main cutting edge and a secondary cutting edge. The main cutting edge performs the main cutting power. Accordingly, there is also a main clearance surface and a secondary clearance surface. The rake angle describes the inclination of the rake surface in the axial direction of the turned part. However, it can also incline downwards or upwards in the radial direction. This angle is called the inclination angle. With a negative inclination angle, the material is not cut at the tip of the cutting edges, but further out. This puts less strain on the cutting edge corner and reduces the risk of cutting edge breakage. However, negative inclination angles are a disadvantage when finishing, as the inclination of the rake surface directs the chip in the direction of the turned surface and can damage it. A positive angle of inclination is therefore recommended for finishing. A positive rake angle can also be advantageous when machining materials that tend to stick. The corner angle is formed by the main and secondary cutting edges. The larger the corner angle, the greater the stability of the cutting edge and the risk of cutting edge breakage is reduced. In addition, the larger surface improves heat dissipation and the thermal load on the cutting edge is reduced (longer service life). The corner where the rake face and the flanks touch is called the cutting edge corner. The cutting edge corner is not pointed, but rounded due to the better stability of the cutting edge. The corresponding radius is called the corner radius or cutting edge radius. Large corner radii lead to stable cutting edges and allow high feed rates and large cutting depths, as are required for roughing. In addition, the large rounding improves heat dissipation. However, due to the larger contact surface on the rounding with large corner radii, high radial forces arise, which can lead to vibrations. This then worsens the surface quality, the shape accuracy and the dimensional stability. In these cases, a smaller corner radius should be selected (finishing). Corner radii should be selected so that they are smaller than the cutting depth for a high surface quality! In addition, the feed rate when roughing should be less than half the corner radius. When finishing, the feed rate should not be greater than a third of the corner radius. The angle that forms between the main cutting edge and the workpiece surface to be produced during turning is known as the setting angle kappa. The setting angle influences the chip breaking, the forces that occur and thus in turn the tendency to vibration. The smaller the setting angle, the longer the cutting edge in engagement and the better the cutting forces are distributed. Setting angles of 90° or more are required when producing right-angled shoulders. The setting angle also influences the forces acting on the turning tool or on the turned part. A force decomposition shows that the normal force of the cutting edge can be broken down into an axial component (feed force) and a radial component (passive force). The radial passive force tries to push the workpiece away and causes vibrations. However, the passive force can be significantly reduced if larger setting angles are selected. Chip breakers are steps incorporated behind the tool cutting edge that are located directly on the chip surface. The resulting chips are diverted at these geometries so that they break at regular intervals. In this way, long flowing chips are avoided and short-breaking chips are produced. Chip breakers can have very different geometries. Here, it is important to pay attention to the manufacturers' more precise information. 00:00 Turning process 00:25 Turning process (longitudinal cylindrical turning) 01:16 Structure of a lathe 01:53 Longitudinal cylindrical turning 02:32 Geometry of turning tools with indexable inserts 03:37 Clearance angle, wedge angle and rake angle 04:05 Inclination angle 05:11 Influence of the inclination angle on chip formation 07:04 Corner angle epsilon 07:40 Corner radius 09:01 Setting angle 10:20 Passive force and feed force 12:22 Corner radius, setting angle and cutting depth 12:57 Wear 14:49 Cross-face turning 15:37 Thread turning 17:27 Flank clearance angle 18:02 Full profile, partial profile and multi-tooth indexable insert 19:49 Plunge turning 20:30 Parting off turning 20:39 Profile turning 20:59 Left, right and neutral clamping holders 22:05 Internal turning tools, boring bars 22:36 Standardization of indexable inserts (ISO 1832) 25:38 Chip breaker