CNC Milling Process
Why is the CNC milling process so important
• Small innovations bring your ideas to life •
The CNC milling process allows us to produce almost anything within tight tolerances. Our precision engineers regularly mill aluminium, plastic, stainless steel, brass, bronze, and more. These components come in a variety of different grades to customers in the UK and the wider world.
Our team has plenty of high-speed CNC machinery that manufactures parts on time – every time – so you can stay ahead of schedule. We communicate well with customers, take care of the projects placed in our care and are consistent in our delivery service. Better still, our team is proud to be ISO9001:2015 accredited and adhere to a stringent quality management system. If you still need convincing of Entech’s outstanding reputation, please read our testimonials or get in touch.
Trusted across multiple industries
Entech helps supply high-quality precision to a wide range of industries. Our CNC milling process proudly creates parts for mechanical engineers in the following industries and more:
Aerospace | Leisure | MOD | Motor Trade
How does the CNC milling process work?
Thanks to its unrivalled versatility and reliability, CNC milling is now a staple of modern manufacturing. From first-hand experience our team know that it’s responsible for a multitude of products – and is used by the MOD through to the motor trade.
But what is the CNC milling process, and how does it work?
Computer-Aided Design
CAD is favoured in many industries due to its accuracy, consistency and ability for high production rates and uniformity.
Once coordinates are established, minimum human input is needed. Yet, before the process begins, our team manually fits the machine with the correct tools and the raw material – or workpiece. Once in place, the operator launches the program using the machine interface. The computerised controls then produce custom-designed high-quality parts with an ultra-precise finish.
Types of CNC Milling
To make a CNC milled part, a workpiece is fitted below a spindle holding a cutting tool. A computer controls the tool, the rotation speed and vertical motion of the spindle, plus the horizontal motion of the workpiece. This allows loaded cutters such as drills, taps and end mills to remove portions of the material to create the desired shapes. It’s these shapes that function as the desired part.
With this said, there are four main types of milling, which are:
Plain Milling
Face Milling
Angular Milling
Form Milling
The CNC milling process explained
CNC, or Computer Numerical Control, is under the direct guidance of a computerised operating system.
Successful, high-quality milling is a combination of three elements:
- A cutter outfitted with plenty of teeth of ideal sharpness for a specific material
- Spinning said tool at high enough speeds to process a material correctly
- An appropriate feed rate for advancing the chosen material through the process
CNC allows for extremely close control of these elements. The computerised system reads design information directly from an engineer’s drawings or models. Doing so eliminates any errors in design and production. The CNC milling process takes directions from custom software codes such as NC code, G-code, and ISO code. These codes are converted straight from CAM or CAD designs. Said codes translate into the machine’s controls, which function on at least two axes (X and Y). In addition to this, the tool spindle runs on the Z-axis. Yet, some projects necessitate controls on up to five unique axes.
Depending on various factors, some milling machines will be more appropriate to your needs than others.
The complexity of the CNC milling process depends on the design of the final part. The more structurally important and high-end the part or product is – the more complex the design. Intricate designs that require high precision – such as medical parts or aerospace components – necessitate complex machines. Otherwise, we will struggle to achieve the final design, finish and aesthetic. More basic parts machined for general use might not require high precision or a high-quality finish. However, complex and intricate designs will often require additional milling. Milling machines utilise either 3, 4 or 5 axes. Yet, fewer axes are needed to achieve the final design of simpler designs. Cutting tools are attached to a spindle that works on 3 linear axes.
In general, simple geometries can utilise a 3-axis milling machine.
3-axis machines are easy to program, operate, and achieve excellent accuracy at low costs.
The cutting tools in question spin at thousands of RPM. This means even the sturdiest of materials can be cut with ease, accuracy and efficiency. 3-axis machines are the most common variety of milling machines and can cut vertically (Z-axis) and in an X and Y direction. However, it’s not normally possible to machine undercuts (features inaccessible with a standard end mill). Therefore, more complex designs may require a more complex milling machine.
The 4-axis milling machine is more sophisticated.
In short, it features the added ability to rotate on the X-axis (similar to a lathe).
5-axis milling machines include rotation in both the X and Y-axis.
These milling machines are implemented for highly complex designs. These may be medical devices and implants for the medical industry or impellers and aerospace structures.
The amount of material the mill can remove depends on two things. The diameter of the mill and the hardness of the material. As a rule of thumb, the maximum thickness posed for removal in one go is the diameter of the milling tool. If the material is thicker than the mill can remove, the mill has to go through the material multiple times. Since there are many variables, it is good to investigate which options are available. Investigate how choices are implemented in the machine you choose to get the most efficient and productive machine. For example, the software must deal with varying thicknesses and dimensions of the hole. It must do so without operator intervention too. For more complex shapes, it’s a process with virtually unlimited freedom and a far higher processing speed.
What is the CNC milling process?
It’s a form of subtractive manufacturing
The CNC milling process is a specific subsection of CNC machining. Computer Numerically Controlled (CNC) machining relies on pre-programmed software to dictate subtractive manufacturing. Coordinates are controlled by previous commands so minimum human input is needed. Many industries favour this due to its accuracy, consistency and ability for high production and uniformity.
Milling itself is a process whereby a milling tool cuts away the material in a rotary motion. This tool is mounted on a rotating spindle that selectively removes material from a block of a raw substrate, known as a workpiece. Sophisticated CNC milling machines can have five or more axes of independent motion. This allows them to create complex shapes or avoid having to move the workpiece to a separate machine. Similar to drilling, this process utilises a wide array of multipoint tools, each with varying diameters and strengths. It is the rapid rotational speed of the mill that achieves a clean finish in the milled hole.
Contact Entech about our CNC milling process
• Quality precision engineering services •
9 Virage Business Park
132-134 Stanley Green Road
Poole, Dorset
BH15 3AP