January 5, 2022

What is the milling process?

What is the milling process, you ask! Welcome to the enchanting realm of woodworking, where boards become art and even splinters earn respect. Greetings, woodworkers and the curious! Have you ever wondered about the alchemy that transforms simple wood into stunning masterpieces? No need to worry! We are here to help you unlock the ancient secrets of milling. Prepare for a journey where wood discovers its true purpose and craftsmanship shines. Grab your goggles, unleash your inner woodsman, and let us dive into the fascinating world of woodworking! But beware: knots have a character all their own here, and the age-old adage “measure twice, cut once” takes on new meaning. Join us as we gather wisdom and uncover the exciting secrets of milling like never before!

What is milling

Milling is a process that involves the use of milling or cutting tools to remove material from the surface of a workpiece. The milling process uses cutting tools rotating at set speeds. Bring the cutting tools with the workpiece to start removing materials when they come with the workpiece.

Milling removes crevices from the surfaces of metals that cause corrosion. It gets rid of excess material from the surface of a workpiece. The process prepares metals for the application of corrosion-resistant coating. Milling machines feature horizontal milling machines with horizontal spindle. Like the name, the cutting tool is on this horizontal spindle. Feed the cable in a vertical, cross, or horizontal direction.

Universal milling machines are milling machines that perform all kinds of milling operations. They feature a table with all motions and a dividing head with change gears. The table can pivot at any angle up to 45 degrees in both directions. Simplex milling machines feature a spindle that only travels in one milling direction. Most of these machines only travel in a vertical direction.

Duplex milling machines are two milling machines positioned opposite each other. These either work independently as or as one machine with two simultaneous spindles. They travel both horizontally and vertically. Triplex milling machines have a spindle that can travel in all three axes, such as XY and Z.

CNC milling process

A CNC milling machine uses a rotating cutter in a cylindrical shape. The plasma cutter moves in multiple Axes. The plasma cutter creates slots and holes in the material that later turns into a part. Standard machines operate on three to five axes. That makes precise cuts and more detail than on 2 Axis.

Modern CNC milling machines are either horizontal or vertical machine centers. They accommodate plastics, ceramics, and composite materials. Several technical features are part of the milling machine, such as automatic tool changers and magazines.
Coolant systems have longer hours of operating the machine without feeling the heat. The plasma machines run smoothly without manual help. That reduces fatigue since the user is more of an operator than running the plasma machine. The vertical milling machine has a vertically oriented spindle axis.

It has long and thin cutting tools, whereas the horizontal machine has shorter and thicker ones. Vertical plasma machines are more versatile than horizontal machines. CNC milling machines come in different sizes that fit multiple sizes and businesses. It is reliable, and I urge you to consider your needs before one.

Types of the milling process

Slot Milling

The process features the cutter’s width less than the workpiece’s width. It makes a slot in the workpiece using thin cutters. To cut the piece in two, make a thin slot go through the depth of the workpiece.

Side Milling

The process is when you produce a flat vertical surface in the workpiece. The depth of the cut is manipulated by rotating the vertical feed screw of the table.

Straddle Milling

It is when you need two or more parallel vertical surfaces machined in a single cut. Complete the process by mounting two side milling cutters on the same arbor as you set them apart such that they straddle the workpiece.

CNC Milling Operations

Up (and Down) Milling

It is also known as conventional milling. Up milling is when the cutter rotates against the direction of the table feed. In contrast, down milling involves a milling cutter that rotates along the direction of the table feed. The difference lies in the load. In up milling, the chip load on teeth increases gradually, while in down milling, the chip load decreases.

Form Milling

The form milling process allows the machining of special contours made of curves and straight lines in a single cut. This is made possible with formed cutters, shaped to the contour of the cut, or with a fly cutter ground. It has to be specifically for the job. Standard form milling involves milling half-round recesses on the workpiece.

Turret Milling

Turret milling is done by drilling, cutting, and shearing. The spindle is stationary during milling, while the table moves along the X and Y axes. This process is for lighter operations.

Types of Milling Machines

There is a wide variety of milling machines. Let’s delve into the main types and what they can do:

  • Horizontal or Plain Milling Machine: A classic choice for basic milling tasks, with the spindle positioned horizontally.
  • Vertical Milling Machine: A vertically oriented spindle offers versatility and precision for various milling operations.
  • Universal Milling Machine: This type allows horizontal and vertical milling, offering greater flexibility for complex projects.
  • Simplex Milling Machine: Ideal for single-point cutting tasks, this machine simplifies the milling process.
  • Duplex Milling Machine: Doubling productivity enables simultaneous milling on both sides of the workpiece.
  • Triplex Milling Machine: Taking it up a notch, this machine allows for milling on three sides simultaneously, boosting efficiency.
  • Rotary Table Milling Machine: Equipped with a rotating table, this machine facilitates the milling of circular or curved surfaces.
  • Tracer Controlled Milling Machine: This machine can replicate intricate patterns or templates and is perfect for precision work.

Each type of milling machine brings its capabilities to meet the varying demands of woodworking. Whether you’re a hobbyist or a seasoned professional, there’s a milling machine that can help you bring your projects to life!

What Is a Milling Cutter

A milling cutter is an important tool used in machines or machining centers for milling operations. These tools remove material as they move in the milling machine, shaping and carving the workpiece to achieve the desired result.

CNC milling machine function

It removes materials from a workpiece. The main function of a CNC milling machine is to remove materials from a workpiece. Using computer-controlled motion and rotating cutting tools, CNC milling machines precisely cut the material to shape and create the desired product. This process allows for precisely producing intricate parts and components used in various industries.

Milling machine parts

Column and Base

The column comes with a base, and the casting supports all other parts of the milling machine. The column features an oil reservoir and a pump that lubricates the spindle. It rests on the base, and the knee base has a coolant reservoir and a pump. These are required to cool off the milling machine during teaching operations.


The knee is a casting that supports the saddle and table. All gearing mechanisms are within the knee. It is secured to the column by dovetail ways, supported, and adjusted by a vertical positioning screw. That is the elevating screw. It adjusts the knee up and down, raising or lowering the lever. Use the help of a hand or power feed.


It is a rectangular casting that comes on the top of the saddle. It holds the work or work holding devices. The table comes with multiple T-slots holding the work and work holding devices. You are allowed to control the table by hand or by power. To move the table by hand, engage and turn the longitudinal hand crank. To move it through power, engage the longitudinal direction feed control lever.


It is the shaft used to hold and drive the cutting tools of the milling machine and mount the spindle on the bearings supported by the column. Move the gear trains by the electric motor. The gear trains are inside the column.

Milling machine uses

Milling machines are versatile and can perform various jobs, including:

  • Drilling: Milling machines can be equipped with a drill to drill holes in the workpiece.
  • Enlarging existing holes: Using special tools, milling machines can accurately enlarge existing holes or create precise cylindrical cavities.
  • Gear cutting: Milling machines can be used to cut gears, enabling the manufacture of gear components used in various mechanical systems.
  • Slot milling: With the appropriate cutting tools, milling machines can make slots or grooves in the workpiece that enable inserting other components or facilitate the assembly process.

Face milling

Face milling is the milling of flat surfaces at right angles to the cutter’s axis of rotation. It removes the material by rotating the facing tool in a counterclockwise direction. At the same time, the table feeds the workpiece across the cutter.

Gang Milling

Gang milling is a process whereby more than two milling cutters are involved in a setup like horizontal milling. All the cutters perform a uniform operation, and the milling cutter may also perform distinct operations. This operation is ideal for producing duplicate parts.

Vertical Milling Machines

Vertical milling machines have the spindle perpendicular to the table. The spindle head is fixed to a vertical column that rotates at an angle, and the cutting head is on the spindle. Vertical milling machines allow the adjustment of the spindle either upwards or downwards. These machines are for precision work.

Horizontal Milling Machines

A horizontal milling machine is a tool with a spindle parallel to the worktable. It is for processing various planes, inclined planes, and grooves with cylindrical milling cutters, disc cutters, angle cutters, forming cutters, end mills, and more tools.

David D. Hughes

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