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How Small Can a CNC Machine Cut?

CNC stands for Computer Numerical Control and represents one of two popular methods (the FDM) used in 3D printing technology to generate prototypes from digital software files. It is a programmed code representing directions for precise movements that are to be carried out by machines. Indirectly, this code dictates how to create or transform something virtual into something real.

Given the definition of CNC, it follows that CNC machines need to interact with software-equipped computers that can convert codes into cartesian coordinates. This allows the machine to deliver a performance with robot-like precision.

Since you’ll be using this tool for 3D carving and other related activities, you’ll want to know what type of CNC machines are out there and how small and precise they cut, among other specifics that can impact your venture.

Those and other important info about the CNC machine are what we’ll discuss today to help you decide if it is really an essential tool for your project.

How the CNC Machine Works

In general, machining is the process of converting stock pieces of materials into plastic blocks before eventually being formed into finished products, usually the prototype versions. This happens through a controlled material removal procedure.

In a similar fashion to other forms of prototype development technology, CNC depends on instructions delivered digitally through a Computer Aided Design or Computer Aided Manufacturing file. The tool then interprets the design as directions on how to cut the sections of a prototype.

How a user can program computer devices to dictate the behavior of these machine tools goes a long way to improving shop productivity. That is because such expertise can automate every highly technical and labor-intensive step involved in the process.

Automated cuts enhance the accuracy and speed with which the parts of the prototype are transformed or produced. That is especially crucial when you use delicate materials like polypropylene.

Some machining processes may involve multiple methods and tools to form the desired cuts. CNC machines are usually able to combine tools into single cells or units. One or two axes is the extent to which most basic machines can move, while advanced models can usually make lateral movements across the “x” and “y” axes and longitudinal movements in the “z“.

With multi-axis machines, parts can be flipped over instantly, allowing the removal of the materials situated underneath. This way, you don’t have to flip the prototype material, and you can cut on all sides without manual intervention. This would usually result in more accurate finished products because automated cuts are generally more precise than cuts achieved through manual input.

That said, manual intervention does have its advantages in the finishing phase. At this point, you need to do etching, which you can accomplish better by hand. This goes for creating simple cuts, too, which typically requires extensive design work to program for automation.

CNC Machine Types

There are two general categories for CNC machines, namely: conventional technologies and novel technologies. In this section, we’ll give you a brief overview of the machines that fall under each category.


CNC machines that operate using conventional technologies are:

1. Drills

This machine spins a drill bit and moves it about and into contact with a motionless block of stock material.

2. Lathes

A lathe works inversely as the drill, spinning the block of stock material against the drill instead of the other way around. It will usually make contact with the material via the lateral movement of the cutting tool, which gradually touches the rotating material.

3. Milling Machines

This CNC machine is arguably the most commonly used today. It makes use of rotating cutting tools to carve off materials from the stock unit. It also comes in several types, including the industrial CNC mill and the small CNC mill, which you can use for smaller-scale projects.


Then, we have the tools that make use of novel technologies.

1. Electrical and Chemical Machining

The machines under this category perform electromechanical, photochemical, electron beam, and electrical discharge machining. These tools are typically used in special situations involving mass production of a specific material type.

2. Other Mediums for Cutting

Aside from the spinning cutting tools used by conventional technologies, other cutting mediums offered by novel machines can also be accessed. Some of the means these tools use for cutting include laser, oxy-fuel, water-jet, and plasma.

The Smallest a CNC Machine Can Cut

A CNC machine with standard cutting tools can cut holes and cavities as tiny as 2.5mm or one-tenth of an inch on stock material. However, this is usually the limit since anything lower would require a different kind of machining, known as micro-machining, to perform accurately. That said, this method should only be performed on an as-needed basis.

Final Thoughts

There’s a lot that goes into choosing a CNC machine. You have to be aware of what types of machines are out there, and how small and precise they can cut for you to properly assess if they’re suited for your specific cutting project. There are also plenty of other factors to consider depending on your personal preferences and business requirements.