CNC plunge milling, also called z-axis milling, is a

CNC Numerical control (also computer numerical control, and commonly called CNC) is the automated control of machining tools (such as drills, lathes, mills, grinders, routers and 3D printers) by means of a computer. A CNC machine processes a p ...

milling process. In this process, the feed is provided linearly along the tool

axis An axis (plural ''axes'') is an imaginary line around which an object rotates or is symmetrical. Axis may also refer to: Mathematics * Axis of rotation: see rotation around a fixed axis * Axis (mathematics), a designator for a Cartesian-coordinat ...

while doing CNC processing.

Plunge milling is effective for the rough machining process of complex shape or free form shapes like

impeller An impeller or impellor is a rotor used to increase the pressure and flow of a fluid. It is the opposite of a turbine, which extracts energy from, and reduces the pressure of, a flowing fluid. In pumps An impeller is a rotating componen ...

parts. In multi axis plunge milling, the optimization of plunge cutter section selection and generating the tool path for free form surface is very important to improve the efficiency and effectiveness. In plunge milling, after each plunge the

milling cutter Milling cutters are cutting tools typically used in milling machines or machining centres to perform milling operations (and occasionally in other machine tools). They remove material by their movement within the machine (e.g., a ball nose mill ...

is offset by some value and then the material surface is removed in the form of lunula. The

material removal rate Material removal rate (MRR) is the amount of material removed per time unit (usually per minute) when performing machining operations such as using a lathe or milling machine. The more material removed per minute, the higher the material remova ...

is computed by area of lunula and the

feed rate The phrase speeds and feeds or feeds and speeds refers to two separate velocities in machine tool practice, cutting speed and feed rate. They are often considered as a pair because of their combined effect on the cutting process. Each, however, ...

. At the entry and exit of milling cutter, the radial offset has not any influence on the condition of surface. At the maximum cutting velocity, the surface obtained is clean whatever the feed rate per tooth on entry but on exit the high value of feed rate gives the deteriorated surface. The surface roughness value always increases with feed rate in plunge milling. The simulation of dynamic uncut chip thickness which is generated by plunge milling can be done by tracking the position of plunge cutter center. This simulation shows the regenerative effect with variation of phase difference. Then the model of uncut chip thickness and cutting force coefficient with cutting edge radius are entered into time domain model. Finally, with the help of time domain solution the stability of machine and vibrations are estimated. The cutting parameters play a key role in plunge milling. The cutting force and machine stability both are influenced by machining parameters. Frequency

domain model In software engineering, a domain model is a conceptual model of the domain that incorporates both behavior and data.Fowler, Martin. ''Patterns of Enterprise Application Architecture''. Addison Wesley, 2003, p. 116. In ontology engineering, a do ...

can be used to estimate the machining stability.

Advantages of CNC plunge milling

The plunge milling has following advantage over conventional milling- #The radial cutting forces, which is responsible for the deformation of the tool and the workpiece, is very small. #The material which is difficult to cut can be rough machined easily. #Comparing to conventional milling, in CNC plunge milling the feed per tooth is less. #The

vibration Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. The word comes from Latin ''vibrationem'' ("shaking, brandishing"). The oscillations may be periodic, such as the motion of a pendulum—or random, su ...

can be avoided in the machine so that is why it is suitable for deep cavity machining like mould and cavity making. In deep milling, the overhang of large length tool is also adjusted.

References

{{reflist * * * * Plunge milling Metalworking

Advantages of CNC plunge milling

See also

References