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Difference Between CNC Milling And CNC Drilling

Austin Peng
Published 6 Mar 2024

CNC machining is a computerized numeric control subtractive machining process. It is mainly used to remove the material from the workpiece to obtain the required parameters. In this article, we will discuss the differences between CNC milling and CNC drilling processes. Its applications, tools selection, pros, and cons are also discussed in this article. DEK provides machining and manufacturing services for rapid prototyping, low-volume production, and mass production. We are extremely concerned about its product quality and customer satisfaction.

CNC Milling Process and CNC Drilling Process

CNC milling and CNC drilling are the most commonly used machining processes in a machine shop. Both processes are used to remove material from the workpiece but their applications and work principle are different. Understanding the differences between these two processes is important while working in the manufacturing industry.

Benefits and Features of CNC Milling


CNC milling is typically used to produce flat surfaces, slots, grooves, racks, and other specific profiles. It helps in developing high-quality, economical, and sustainable parts in minimum lead time. Some of the benefits and features of CNC milling are as below.

  • It is ideal for rapid prototyping and mass production.
  • It requires less lead time and thousands of milling parts can be produced in a short period of time.
  • It produces parts with extreme precision and accuracy.
  • Due to automation, it reduces labor and manufacturing costs.
  • Its multi-axis operations help in developing parts with complex geometries.
  • It comes with high operational reliability, good adaptability, and flexibility.

Benefits and Features of CNC Drilling


CNC drilling is used to perform various drilling operations on the workpiece. It helps in creating Angle, Ball End, Blind, Concentric, thru, and Flat Bottom deep holes. It is also used to perform small hole drilling. Some of the benefits and features of CNC drilling are as below.

  • It is extensively used in manufacturing high-quality molds.
  • It can easily drill a hole up to the depth of 2600 mm and the diameter of 3 – 32 mm.
  • It is capable to drill complex machine parts according to your need.
  • It requires less lead time as compared to manual drilling.
  • It is a computerized numerically controlled machine, produces premium parts with extreme precision.

What are the differences between CNC Milling and CNC Drilling?


Both of the machining processes are used in the machine shop to develop custom parts via subtractive manufacturing. Some of the key differences between these two processes are described below.

Motion Path of Cutting Operation

One of the major differences between these two processors is their motion path to perform the cutting operations. While performing the drilling operation, the cutting attachment moves in the vertical direction to create holes or remove material from the workpiece. On the other hand, milling can be performed in both vertical and horizontal directions for cutting specific shapes, boring, and surface finishing.

Position of the Workpiece

Positioning the workpiece against the cutting tool is another significant difference between CNC milling and CNC drilling. In drilling, the workpiece remains stationary and the cutting tool moves to perform the cutting operation. While performing the milling operation, the workpiece moves freely against the cutting tool to develop the desired shape.


The drilling process can be easily performed with precision on a manual drilling machine whereas, it is hard to perform milling operations manually. Almost all of the milling operations are performed on the CNC machines to maintain product quality. Both of the operations can be performed on a single CNC machine by adjusting the operating parameters of the machine. CNC milling can be performed on the 3-axis, 4-axis, or 5-axis CNC milling machines to produces complex parts with high precision and accuracy. It can operate at X, Y, and Z axes that allow it to perform milling at complex parts.


Before purchasing any equipment or choosing any machining operation, make sure that it fulfills the requirement of your machining process. To execute a complex machining process, other than drilling through the workpiece, we recommend you use a milling machine. The milling machine allows you to perform the following tasks:

  • Producing flat surfaces
  • Engraving complex parts
  • Surface finishing
  • Cutting irregular shapes
  • Cutting slots in the workpiece
  • Develop teeth for gears.

Chips Removal

Drilling has been performed in a narrow hole so the cutting chips are discharged through the groove of the drill bit. Some of the common types of chips generated as a result of drilling is tubular chips, spiral chips, and flake chips. The continuous chips are formed during the milling process. Chips removal helps in maintaining the high standard of the product and increases the tool life.

Tool Selection for CNC Milling and CNC Drilling


There are a lot of cutting tools used to perform milling and drilling operations. Two main types of tools are;

  1. Double Point Cutting Tool– It has only two cutting edges and typically used to perform drilling operations. In this tool, the two cutting edges are engaged in removing the material from the workpiece. A tool with more than two cutting edges can also be used for drilling operations.
  2. Multi-Point Cutting Tool– In this category of cutting tools, more than two cutting edges are engaged in removing the material from the workpiece. Most of the tools used for performing milling operations are multi-point cutting tools such as Endmills and milling cutters.

What are the applications of CNC Milling and CNC Drilling?


CNC Milling

It is one of the most commonly performed operations in a machine shop. Some of the applications of CNC milling are:

  • It is extensively used to machine flat parts. Flat parts are easy to machine and this process can be performed on the 3-axis CNC milling machine.
  • Some of the variable angle parts and curved parts with complex geometries can also be machined by using a 4-axis CNC milling machine.
  • It can produce intricate parts for artificial bones, automobile products, and aerospace products.

CNC Drilling

It is performed in almost every manufacturing sector for developing holes, grooves, and slots in the material. Some of the applications of CNC drilling are:

  • It is generally used for deep hole drilling and small hole drilling in the workpiece.
  • It is also used for tapping fasteners and fittings.
  • It is typically used in various manufacturing industries like aerospace, automobile, chemical, electronics, food, textile, etc.

Pros and Cons of CNC Milling and Drilling

The pros and cons of using both of these operations are as followed:

CNC Milling


  • It provides flexibility and ease in cutting complex shapes.
  • It provides excellent repeatability by producing several identical parts from a single design.
  • As this machine is computerized numerically controlled, it reduces labor cost and increases productivity.


  • CNC milling machine is expensive and comes in a heavy design.
  • Only highly trained personnel are allowed to operate this machine.
  • In case of any fault, the machine repairing can cost a lot of money and time.

CNC Drilling


  • It provides high accuracy and excellent repeatability.
  • It can drill holes in complex structures at high speed with extreme precision and increases productivity.
  • Due to its lightweight design, it is preferred to use for low-volume production.


  • Its repair and maintenance are complex and costly.
  • It comes with a limited cutting motion.


After doing thorough in-depth discussion on the differences between CNC milling and CNC drilling, now you can easily select the suitable process for your required product. We found that CNC milling is a bit complex and a lot of machining processes can be performed on this single machine. On the other hand, CNC drilling is limited with its operations and is typically used to drill holes in the workpiece. Both of the processes are used to produce high-quality parts that meet the requirements of every specific individual.

If you are looking for a CNC machining expert for rapid prototyping, low volume production, and mass production then DEK should be your first choice. We produce high-quality custom products for our clients around the globe. DEK is equipped with modern CNC machines that produce top-notch, affordable, and sustainable products for almost every industrial sector. Place your order today at DEK machining and manufacturing services and receive it at your doorstep. You can also contact our team for technical support.

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Austin Peng
Co-founder of DEK
Hello! I'm Austin Peng. I manage a factory that specializes in CNC machining, injection molding, and sheet metal fabrication for small quantity production and rapid prototyping solutions. When I'm not immersed in work, I love diving into football matches, exploring new travel destinations, enjoying music, and staying updated on the latest tech trends. Feel free to chat with me about anything, whether it's work or life!


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