High stock removal
From Wikipedia, the free encyclopedia
High stock removal is a technological process with the goal of removing large amounts of material. The quantity of material which can be removed by a specific process depends on the material properties and the machining tool used.
Specific energy
The stock removal rate is largely a function of the material's properties. This is expressed as the machinability of a material: the ease or difficulty of machining a particular material. The machinability of materials varies greatly; for instance, aluminium and magnesium have high machinability compared to titanium and other special metals.
One way of quantifying the machinability of a material is to measure specific energy (e): this is the amount of energy required to cut a given volume of work material (kWh/mm3), and varies with material properties.
New materials
New materials are continuously developed to address the extreme demands of market segments such as petrochemical and aerospace. Metallurgical advances have produced a wide range of high-performance materials (e.g. titanium and high-nickel alloys), but a consequence of their attractive properties is often that they are difficult to machine.
Temperature rising
The specific cutting energy needed for ‘difficult to machine’ materials can be extremely high. Especially in high stock removal applications, there are problems with thermal load in the work material. An increase of the work material temperature can lead to deterioration of the work material surface integrity, resulting in metallurgical damages like micro-cracks, residual stresses and work hardening. Excessive heat also dramatically shortens tool life.
