May 16, 2021

How Does a CNC Milling Machine Work? A Detailed Guide

A CNC milling machine is a computer-controlled machine tool used for milling. It is a very versatile machine that can perform many operations. In this article, I will explain how a CNC milling machine works. We will see how the control system is built and how the tools and workpieces are related.

A CNC milling machine is one of the most versatile tools in your shop. It is used for milling, drilling, routing, carving, cutting, designing, grinding, and machining. It can machine wood, metal, and plastic. CNC machines use a cutter to remove material from a workpiece using various cutting strategies.


The BobCAD-CAM software is for the CNC milling machine. It has multiple cutting capabilities. It has a CAD design system that allows you to transition from designing your part to assigning tool paths. The CAD-AM software gives you powerful tool path options that give high-speed machining. 

Multi-axis cutting operations make the machine mill high volumes. The CNC programming tools make the machine efficient due to high speed. That creates precise parts. It programs engraving and complex axis milling routines through innovative, efficient, and modern machining options. 

The programming process is quick. It delivers 2 to 5 axis cutting capabilities. The probing feature gives measurements of the 41 probing cycles. The hole feature recognition automatically finds holes and depths.

The whole process is made easy. The steep shallow operations feature is 70 per cent faster in calculating times with surface finishes using a tool path. The barrel mill tool reduces the cycle time. The corner slows down feature I an advanced mapping system that introduces slow cutting motion. 

3D milling gives you multiple machining strategies, and 2D gives you powerful operations. 4D axis milling has advanced rotary and fully supported features. The 5axis milling has multi-axis part programming. 

How it works

A CNC milling machine uses a rotating cutter that comes cylindrical. 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. 

cnc milling machine

Modern CNC milling machines are classified as horizontal and 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 you get one. 

How to operate it

The CNC milling machine requires the management of computer numerically controlled equipment. The equipment has to be set up for operation as it produces parts and tools from different materials. These materials include plastic and metal. The monitoring machine inspects finished products, so there are no chances of giving under-produced parts. 

Test runs are for accuracy and adjustments. As a CNC machine operator, you have to oversee the CNC machines. Quality parts need specific tools. The drawings are engineering-centered. I advise users to undertake high-skilled professionalism to work with the machines. 

Attention to detail is a prerequisite. You must set up and manage the machines as you drill, grind, and mill. The engineering drawings are translated into different dimensions for the production of parts. There are guidelines to be followed. The machines are automatic does not mean you have to fold your hands. You have to be in control. 

There are changes to be made for improved results. Inspect the machinery for quality functionality. There is a need for records keeping on the productions completed and quality logs to be completed. There are timelines to be kept. Expectations are met, and regular CNC machine assessments. Formal training and knowledge are prerequisites to avoid more time and creating poor quality parts. 

The tooling location and dimensions used for cutting have to be known. Running tests allows you to spot technical faults and ensures accuracy. The machine has to be at zero for accuracy in dimensions. The plasma machine is in manual mode by pressing the positive X-axis transverse button for one second. What follows is the press of the Y and Z axis buttons. That allows the machine to set a reference point based on a home position. 

The dial indicator has to be placed on the spindle and move manually. The tip of the indicator is on the front jaw. The tools have to be in a tool turret, and tool teach mode. The machine automatically brings each tool to the probe, and a beep sound is expected. 

The machine determines the depth cuts. The edge finder has to be at 1,000 rpm and bring the edge finder closer to the material. Bring back the spindle to a home position and start the program. Rapids determine the speed of the spindle during tool changes.

How to maintain it

Routine scheduled maintenance must be followed when using a CNC milling machine. Unscheduled routines cost you in repairs and replacements. You point out faults, and that avoids damages. There is a need to look for any material inside the machine for removal. 

Cleaning and wiping your machine is a must so that no debris will damage your milling machine. Monitor the machine’s fluids and grease on the moving parts. Apply lubricants to avoid friction.  

That is proper management of fluids. Spare parts have to be on standby to avoid delays in breakdowns. Waiting for spare parts to be shipped takes forever, and you do not want inconveniences. Quick shipping costs more, and you have ample time to compare and decide on prices and brands. The guide rail should stay clean. There has to be a stable external power supply. 

Warming up the machine after a long period not in use is key. The filter of the oil cooler needs regular cleaning. The water in the air source is emptied in time. The tool coolant valve needs to cool. The emergency stop button has to be pressed immediately in case of unusual situations.  

Other peripheral equipment

Gravity and high-pressure coolant

That prevents high chances of wear to the machine. The surface finish is preserved. It makes the plasma machine safe to use.

Chip conveyor

It traps chips from falling out of the machine. 3D surfacing produces thin chips that fall out hence the need for a chip conveyor. Chips in the coolant lead to the breakdown of the plasma machine.

Why you should use a CNC Mill

  • It is cost-effective since one operator runs multiple machines. 
  • Accurate 
  • There is maximum production due to increased speed
  • Efficiency
  • It is safe
  • Durable construction
  • Handles large and heavy machines without getting damaged
  • Flexible computer controls
  • Reduces chances of human error.
  • Use of multiple cutters
  • Produces complicated shapes


If you are looking for the ultimate precision and control, a computer numerical controlled (CNC) milling machine may be what you need. Computer numerical control software is a program you use on your computer to design things before sending them to the CNC mill. 

It is hard to make mistakes because you can fix them post-processing without redoing any parts from scratch. so that they can turn out high-quality work with minimal effort. This technology is good when you have a tight tolerance, like in manufacturing. 

You can also use it for large volumes, like manufacturing. But it isn’t limited to those industries – hobbyists also find this technology useful. It is better to use a milling machine than a hand tool. With the machine, you can see what you are making on the screen and make changes as needed. We offer several different types of mills at our store, so come by today to find the one that best suits your needs. Find out How to Use a CNC Plasma Cutter.


What is face milling?

Face milling refers to milling operations in which the cutting tool’s axis of rotation is perpendicular to the surface of the workpiece.

What is Milling?

It’s a machining type that uses cutters to shape a workpiece, often on a moveable tabletop, although some milling machines also feature movable cutters.

What is the difference between CNC and manual milling?

Milling started as a manual task performed by humans, but most milling these days is done by a CNC mill, which utilizes a computer to oversee the milling process.

What Is a CNC Milling Machine?

A horizontal CNC milling machine (also known as a CNC mill) performing a milling operation on a metal part.

What is the process?

CNC milling, or computer numerical control milling, is a machining process that employs computerized controls and rotating multipoint cutting tools to progressively remove material from the workpiece and produce a custom-designed part or product.

What is CNC Machining?

CNC milling is a mechanical process along with drilling, turning, and various other machining processes, meaning that material is removed from the workpiece via mechanical means, such as the milling machine’s cutting tools.

What is CNC Milling?

CNC milling is a machining process suitable for producing high accuracy, high tolerance parts in prototype, one-off, and small to medium production runs.

What tolerances can you achieve with a milling machine?

To +/- 0.005 in., some milling machines can achieve tolerances of up to and greater than +/- 0.0005 in.

What are the different types of CNC milling operations?

The most common CNC milling operations include: Face milling, Plain milling, Angular milling Form milling

What Is Plain Milling?

Plain milling, also known as surface or slab milling, refers to milling operations in which the cutting tool’s axis of rotation is parallel to the surface of the workpiece.

What are the different types of milling cutters?

Depending on the specifications of the milling application, such as the cut’s depth and the workpiece’s size, both narrow and wide cutters are used.

What is a conventional mechanical CNC machining process?

Conventional mechanical CNC machining processes the CNC milling process utilizes computerized controls to operate and manipulate machine tools that cut and shape stock material.

What is a CNC program?

Then the completed design is exported to a CNC-compatible file format and converted by CAM software into a CNC machine program that dictates the machine’s actions and the movements of the tooling across the workpiece. 

What is the difference between a CNC mill and a router?

A CNC mill has X-Y Configuration, which means the spindle with router bits attached is set above the device, making the spindle move on a linear axis, giving it better precision than a CNC router. CNC mills are better than CNC routers because a mill machine can even cut metal with 1,000th of an inch precision which is why they are mostly used in industries with tiny errors.

What are the RPM counts?

The RPM count for a CNC router ranges between 13,000-18,000, but it is between 800-1000 RPMs for a milling machine.

What are the benefits of CNC mills?

But these powerful machines offer a wide range of other benefits, particularly in manipulating most materials efficiently.

What is a CNC mill?

On the other hand, a CNC mill works mostly on cutting all types of materials like hard plastic, wood, and metals such as titanium and strong alloys. A mill machine is usually much stronger than a CNC router since it is used to cut heavy metals and is mostly used for industrial purposes.

What is the best way to program a CNC mill?

It would be best if you programmed more advanced mills with CAM technology to run properly.

What are the appropriate CNC machine tools?

However, most CNC mill machines work with metal materials. Much like drilling and cutting processes, the appropriate CNC machine tools must be chosen for each material used.

What axes can you have on a CNC machine?

CNC machines can have several axes of movement, either linear or rotary.

What is a five-axis milling machine?

A five-axis milling machine has three linear axes and two rotaries, allowing the cutter to operate in a full 180º hemisphere and sometimes more.

What are the limitations of CNC machines?

Depending on their age and sophistication, CNC machines can be limited to the capabilities of their control and drive systems.

What is the difference between a five-axis machine and one?

All five must be perfectly synchronized in the five-axis machines – no easy task.

What is the difference between a new computer and an old one?

Older and less expensive machines are obviously less capable in this, much like an older computer will work less well and more slowly (if at all) on demanding tasks than a newer one.

What is CNC?

CNC – Computer Numerical Control – Taking digitized data, a computer and CAM program is used to control, automate, and monitor the movements of a machine.

What are the benefits of desktop machines?

These are generally lighter, less rigid, less precise, slower, and less expensive than their industrial counterparts. They can do well for machining objects out of softer materials such as plastics, foam, and wax.

What is CAM programming?

CAM – Computer Aided Machining or Manufacturing – Refers to using various software packages to create toolpaths and NC code to run a CNC controlled machine based on 3D computer model (CAD) data.

What is a typical problem with CAM programming?

A typical problem is setting up your files and doing your CAM programming so that the machine executing your parts will work smoothly and efficiently with the data.

What are the benefits of going finer?

Going finer increases the smoothness of the approximation but also dramatically increases the number of segments.

What are the benefits of arc conversion?

You can imagine that a series of arcs might be able to approximate your spline within tolerance with fewer, longer pieces.

What is the movement system?

The movement of your CNC along the coordinate system is always based on how your tool moves, not the table.

How does a CNC machine work?

So far, we’ve talked about how a CNC machine uses its internal coordinate system.

How do I find an origin point for my WCS?

Once an origin point is established, you need to locate it inside your CNC machine using an edge finder, dial indicator, probe, or other locating methods.

What is the origin point of a CNC machine?

Every CNC machine has its internal origin point called Machine Home.

What happens when a machine reaches its limit?

Once a limit is reached, a signal is sent to a controller that records the particular axis’s home position.

What is a machine controller?

A machine controller sends a signal through a circuit board to a servo motor, connecting to each axis.

How does a motor work?

The servo motor rotates a ball screw attached to the table on your CNC machine, making it move.

How do I know if the axes are aligned correctly?

Place your hand in front of your CNC machine, aligned with the machine’s spindle, and you’ll see the axes line up perfectly.

David D. Hughes

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