What is CNC Milling?

What is CNC Milling?

What is Geomiq's CNC Milling Service?

This article delves into the workings of CNC milling – a subtractive manufacturing process – by discussing the operations of CNC milling machines, the types of parts that can be produced through milling, and the optimal design practices for maximising the benefits of CNC machining.

CNC milling is a machining method that merges computer numerical control machining systems with a milling cutter or multi-point cutting tool. It belongs to a class of CNC manufacturing and involves securing the workpiece on a machine bed and carving out materials from a solid block to fabricate products made from various materials, including but not limited to glass, metal, plastic, wood, and other specialised materials.

This article explains the operations of CNC milling machines, outlines the various kinds of CNC milling machines, and offers recommendations on designing for optimal performance in CNC manufacturing.

How do CNC Milling Machines work?

1. Producing a CAD model

Design software, such as Solidworks and Autodesk Fusion 360, is used by engineers and machinists to produce a CAD model of their specific components.

2. Convert CAD model for CNC machine

The CAD model is then imported into the computer-aided manufacturing system. With proper execution, this process generates a sequence of digital instructions referred to as G-code, which dictates the CNC machine’s actions. These G-code commands specify the machine’s movements and velocities, enabling it to fabricate the desired component accurately.

3. CNC Milling Machine preparation

Firmly Secure the workpiece or block of material onto the machine bed, and make sure it is aligned precisely using metrology tools or touch probes. Proceed to mount the machine spindle and perform all of the necessary steps for configuring the milling machine.


4. Starting the milling process

Commence the CNC milling process by loading the program. Specialised cutting tools, either rotating at high speeds or set to a fixed revolution per minute, are utilised to remove material from the workpiece until it precisely duplicates the desired component.

What is the difference between CNC milling & turning

CNC turning is primarily used to construct cylindrical or conical surfaces. In contrast, the turning procedure necessitates the use of a lathe, which is a machine tool capable of revolving a workpiece around an axis of rotation, of executing various operations, including cutting, drilling, turning, and threading. Furthermore, it utilises a single-point turning tool that stays in direct contact with the workpiece throughout the process.

CNC milling, on the other hand, is utilised to generate flat surfaces using a milling machine. This process involves a multi-point cutting tool or a milling cutter. In contrast to turning, the milling process depends on intermittent cutting and multiple machine steps. 

Cnc milling and turning

Different types of milling machines

Examining the different varieties of milling machines:

3-axis machines enable the cutting tool to remove material by moving through the X, Y, and Z axes. This technique is widely preferred because of its affordable initial expenses and suitability for producing straightforward components with basic shapes.

4-axis machines possess all the functionalities of a 3-axis machine, but with an extra axis that enables the workpiece to rotate for cutting around the A-axis. This feature is especially beneficial when cutting around the side of a component or a cylinder.

5-axis milling machines facilitate movement along three linear axes and rotation of both the machine head and the tool head, thereby providing a total of five combined axes. It is capable of producing components with intricate geometries, such as aerospace parts, medical equipment, titanium pieces, and gas machine components. Since it enables multidimensional rotation, it eliminates the need for multiple setups and enables faster and more efficient single-step machining.

How to get the best value CNC milling quote with Geomiq?

There are several methods to reduce CNC milling costs and hasten lead times. Essentially, much of it comes down to designing parts that are “Simple” and/or “Standard”. Parts with uncomplicated features that can be constructed with standard-sized tooling will typically result in successful outcomes. While complexity may be necessary, it can also lead to increased costs and longer lead times. 

A part with a single complex feature or tight tolerances may not pose a significant challenge when made of aluminum. However, mass production of the same part in plastic can potentially be difficult. In summary, incorporating simplicity and standardisation into your design is advisable. While complex features or specialty materials may be essential at some stage in product development, they can make milling more complex.

Are you ready to supercharge your manufacturing utilising Geomiq’s revolutionary Ai-powered platform? Click the button below to request a CNC quote through our platform.

March 31, 2023

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Disclaimer: The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of Geomiq. Examples of analysis performed within this article are only examples. They should not be utilized in real-world analytic products as they are based only on very limited and dated open source information. Assumptions made within the analysis are not reflective of the position of any Geomiq Employee.