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Four major Types of CNC Milling Operations

CNC Milling

CNC milling has revolutionized the manufacturing landscape, offering unparalleled precision and efficiency. Understanding the various types of CNC milling operations is essential for optimizing production processes and achieving desired outcomes.

CNC milling involves the use of computer numerical control to automate the operation of milling machines. These machines, equipped with cutting tools, remove material from a workpiece to achieve the desired shape. The versatility of CNC milling allows for the creation of complex parts with high accuracy, making it a cornerstone in modern manufacturing.

Four major Types of CNC Milling Operations

CNC milling has several operations with different setups and applications. Below are the common types of operation.

Face Milling

In face milling, the cutting tool’s (face milling cutter) rotating axis is perpendicular to the workpiece surface.

The face milling cutter has a unique design notable in its interchangeable cutter inserts. It delivers cutting action using its multiple cutting teeth. As a result, face-milled parts have higher quality surface finishing. Also, the process is in close control, making it easy to produce your desired surface easily.

Plain Milling

Plain milling is a column and knee operation used for milling plain horizontal surfaces. The cutting tool lies parallel to the workpiece. Therefore, cutting occurs from one end of the workpiece to the other. Operators can feed the table longitudinally, cross, or vertically.

Angular Milling

Angular milling involves milling flat surfaces using a cutting tool at an angle. The process is like plain milling, the only difference being the angular setup.

There are two angular milling cutters: single angle and double angle. The single-angle cutters have teeth on the cutter’s angular face and large flat sides and are suitable for working at angles of 450 or 600.

The double angular milling cutters have V-shaped teeth with conical surfaces and are the better option for milling flat surfaces at 45°, 60°, and 90°.

Form Milling

Form milling is the better method for making irregular contours on a workpiece. The contour can be curved or curved with straight lines. The contours can be concave or convex and are made with teeth opposite such shapes. Consequently, to make a product with a concave edge, the form milling cutter should have a convex edge.

Form milling is a little slower (about 20 to 30%) than regular milling due to the more intricate cutting to make curved surfaces.

Common CNC Milling Tools

  • End Mills: Used for general milling operations, end mills come in various shapes and sizes, including square end mills, ball end mills, and corner radius end mills.
  • Face Mills: Specifically designed for face milling operations, these cutters have a large diameter and multiple inserts for efficient material removal.
  • Slot Drills: Ideal for machining slots and pockets, slot drills have a cutting edge on the bottom and the sides.

Comparison of CNC Milling Operations

Milling OperationCharacteristicsTypical Applications
Face MillingRemoves material from the surface of the workpieceAchieving a smooth finish
Peripheral MillingRemoves material from the outer periphery of the workpieceCreating slots, pockets, contours
DrillingCreates holes in the workpieceHole machining in various components

This table provides a succinct comparison of the characteristics and typical applications of key CNC milling operations, aiding in the selection of the most suitable technique for specific manufacturing needs.


In conclusion, the world of CNC milling operations is rich and diverse, offering a myriad of techniques to suit the specific needs of different manufacturing processes. Face milling, peripheral milling, drilling, pocket milling, and contour milling represent just a fraction of the extensive toolbox available to engineers and machinists. The inclusion of a list detailing common CNC milling tools and a comparative table enhances the comprehensiveness of this exploration, providing a holistic understanding of the types of CNC milling operations and their applications. As industries continue to evolve, CNC milling remains at the forefront, driving innovation and pushing the boundaries of what is achievable in precision manufacturing.