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What is CNC Milling and What is it Used For?

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What is CNC Milling?

Computer Numerical Control (CNC) milling is a subtractive manufacturing process which uses a variety of rotating cutting tools to remove material from a workpiece. It consist of a multi-axis system (three, four, or five axes, depending on the part complexity).



CNC milling tools perform a machining process similar to drilling and cutting parts shapes out of a metal or plastic block of material but with incredible precision, holding dimensions to tolerances as tight as 0.002″. As the name suggests, the cutting tools are programmed and managed by a computerized manufacturing process, leaving no room for human error.

With such accuracy and precision, the process be repeated as many times as desired to achieve a production run of identical parts as fast as 4 days here at HLH Rapid.


3, 4 and 5 Axis Milling Machines

If you are searching for information about CNC machining in general, you’ve likely encountered the phrase ‘3, 4, and 5 axis machines’ frequently. So, what are the differences between these machines? Let’s see:


  • 3-axis milling machines are the most basic type of milling machines. It operates on two axes (the X and Y axis), allowing for vertical cuts in any direction. Due to the limitations of the axes it operates on, there are restrictions to how complex a part it can produce.
  • 4-axis milling machines are more complex because they add the ability to rotate the x-axis, similar to a lathe. It is used for tasks such as engraving, indexing, and machining parts with features on multiple sides.
  • 5-axis milling machines are the most advanced and versatile type of CNC milling machines. They can perform machining operations from multiple angles and orientations, allowing for the production of highly complex and intricate parts with fewer setups and tool changes.


What is 3, 4 and 5 axis milling? and how does it work?


CNC Milling vs CNC Turning

There are various CNC processes fit for different purposes, the two most common processes being CNC turning and CNC milling. Simply put, the difference between turning and milling lies within the way the machine itself or the raw material moves. In CNC turning, the workpiece rotates against a cutting tool, whereas, in CNC milling, the material is held in place while the cutting tools rotate around it.

Due to the difference in movements, some processes will be more suited to milling or turning, respectively. For instance, as a milling machine has up to 5 axes of movement to manage- 3 linear ones in the X, Y and Z planes, as well as two rotational axes, it is better suited for creating more complex and intricate shapes.

Pro Tip: In deciding which CNC machining process is suited to what design, the biggest determining factor is the shape of the part followed by the size of the project.


Why Use CNC Milling For Your Project?


  • High Precision Parts: CNC milling machines are capable of producing highly accurate and precise parts with tight tolerances consistently and reliably.
  • Build Complex Geometries: CNC milling allows for the production of complex shapes and geometries that may be difficult or impossible to achieve using manual milling techniques. This includes intricate 3D contours, curves, undercuts, and features with precise dimensions.
  • Less Labour Intensive: CNC milling tools can spin at thousands of RPM (revolutions per minute), resulting in high production output while also being a time-saving expense. No manual processes could achieve a similar output.
  • Versatile Material Selection: CNC milling machines can work with a wide variety of materials, including metals (such as aluminum, steel, and titanium), plastics, composites, and wood.


CNC milling — commonly used for automotive, aerospace, medical as well as in the production of robotics and automation — can also be used in tandem with CNC turning to add design features, such as flat faces, that are impossible to achieve otherwise.

If you are looking to create fast and repeated highly complex and intricate parts (from 1 to 10,000+ parts), CNC milling is an excellent choice. HLH’s CNC milling services can deliver custom machined parts, in both metal and plastic, four to five times faster than it takes using more traditional machining methods.


Different Types of CNC Processes

Apart from CNC milling, there are several other common types of precision CNC machining processes, including:



Online CNC Machining Services With HLH

In order to take full advantage of the benefits of CNC milling, product designers and engineers must familiarize themselves with the process and considerations. Partnering with an on-demand digital manufacturer like HLH Rapid can be the ticket to faster, more effective design and production.

Submit your CAD designs and project details on our Site Contact Form, and our team will get back with a CNC machining quote (in metal, plastic or carbon fiber) within 1 business day.

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