Milling 101

Milling is basically the process of removing material. It began centuries ago as a way to process grains using stones.

greece ancient athenian agora mill stones 300x195 Milling 101
Ancient Greek Milling Stone










Eventually, it also came to include metal processing with rotating cutting tools. As milling evolved, the array of tools that could be employed increased greatly as did the precision. Choosing the right tool and the proper machining parameters in milling is essential to achieve an optimum outcome.

Types of Milling

Face Milling – Used for making flat surfaces. The cutters usually have a single row of inserts. The tools used for face milling will preferably have a lead angle for long tool life.

Face Milling Machine1 300x300 Milling 101
Face Milling Machine














Slot Milling – Used to produce slot and channels. Mainly, slot milling is done with either a disk mill or an end mill. Disk mills are usually used for operations that are perpendicular to the spindle rotation. Types of disk mills are high-speed steel, brazed carbide, and indexable-insert-based. These will be used for operations perpendicular to the spindle rotation. End mills are used when the slot needed must be parallel to the spindle rotation and often result in poorer quality due to poor chip formation and other factors. End mills have a smaller tool diameter and greater length which causes them to be less stable than all other milling cutters.

PVC Window Water Slot Milling Machine Four Axis LXC01 4  300x240 Milling 101
PVC Window Water Slot Milling Machine











Periphery Milling – Creates a primary surface that is parallel to the spindle rotation. Often times, there is also a secondary surface generated. Types of periphery milling cutters include: solid carbide, high-speed steel, and indexable-insert-based.

Specialty Applications

There are additional types of milling that can be used for specific jobs. Here are a couple:

Ramping – Used for making angled surfaces or for making a pocket at the point of entry.

Helical and Circular Interpolation – Used to create a cylindrical surface or to make entry points that can be used later.




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