There are varying insert geometries available depending on the requirements for each respective cutting tool application. Choosing these geometries depends on the
- cutting material
- material to be worked
- cutting conditions
- tool geometry
The machining process of ‘roughing’ is understood as the removal of material with large chip volume, typically by means of large cutting depths (relative to the whole process). The work piece achieves its near-final contour in this way and with short machining times, albeit still with rough surfaces and low dimensional accuracy. This process is employed for turning and milling in particular.
The surfaces are subsequently smoothed during the ‘finishing’ process, in which the tools remove finer, more minuscule swarf. This is how the work piece finally achieves its exact final contour.
Inserts can have highly diverse forms: the tip angles vary from 35° up to 135°. You can find ISO standard inserts with their respective designations as follows.
The varying geometries are characterised by various chamfers and edge rounding (honed). Distinctions are mainly made between the 4 cutting edge types as follows:
F - sharp: particularly suitable for the finishing of soft materials, which normally deals with uncoated inserts.
E - honed: coated inserts, particularly suitable for steel machining and for interrupted cut, the hone protects the cutting edge.
T - with chamfer: these inserts feature particularly stable cutting edges, where the cutting force increases, and are above all suitable for the machining of hardened steel and chilled castings.
S - with chamfer and hone: maximum machining stability, but increased cutting force, temperature and risk of chatter; particularly suitable for heavy cuts.
Whatever the material, machine, coolant, cutting parameters and surface requirements; achieving optimal swarf control is a must. Badly formed chips interrupt the production process: they can get stuck to the work piece or machine, are very difficult to remove from the machining environment and can damage the work piece surface.