CNC milling is one of the most popular machining methods that has revolutionized manufacturing processes in many industries. Combining traditional milling with computer numerical control (CNC) technology, CNC milling enables the production of parts with complex shapes and high dimensional tolerances that meet the most stringent requirements. In this article, we'll take a closer look at CNC milling technology, its benefits, and applications.
What is CNC milling?
CNC milling (computer numerical control) is a type of machining that allows for the rapid shaping of flat and shaped surfaces using a rotating cutter in the spindle of a machine tool. Spindle movements are controlled by a computer that interprets numerical code and converts it into precise tool movements. This makes it possible to achieve complex shapes and details that would be difficult or even impossible to produce using traditional machining methods.
How does CNC milling work?
The cutter mounted in the spindle (which is part of the milling center) gradually removes the top layer of the workpiece (excess material) to achieve the required size and shape. The movements of the milling head are controlled by a CNC controller, which executes a given sequence of movements in at least one plane. These parameters, such as cutting depth, rotational speed or feed rate, are specified in the program and adapted to the properties of the material being machined and the expected surface quality.
Thanks to the use of computer control (where the movements of the cutter in many planes are controlled by actuators and relays) and the possibility of automating the process of loading and unloading machined elements to the CNC milling machine's workspace, it is possible to:
- Very fast and repeatable production of large quantities of elements - especially compared to traditional manufacturing methods,
- Lower unit cost of part production - especially noticeable for larger projects,
- Maintaining marginal dimensional tolerances between parts made in one batch, and even between different batches,
- Improved work safety,
- Reduced risk of human error and the number of parts rejected during quality control,
- Optimization of the use of human resources - one employee can supervise the work of a larger number of CNC devices (in the case of traditional milling machines, one person can only operate one device within a specified time frame).
These features make CNC milling services indispensable in applications requiring very high production quality and maintaining repeatable dimensions of manufactured elements.
The CNC milling process
The CNC milling process can be divided into several key stages:
- Design: The first step is to create a part design in a CAD (Computer-Aided Design) program. This design contains all information about the shape, dimensions and tolerances of the part.
- Programming: Then, the CAD design is imported into a CAM (Computer-Aided Manufacturing) program, where a control program for the CNC machine is created. This program specifies the tool path, cutting speed, cutting depth, and other machining parameters.
- Machine setup: After preparing the program, the CNC machine is configured for machining. This includes selecting the appropriate tools, fixing the material and setting the machine parameters.
- Machining: After the configuration is completed, the CNC machine starts the machining process, making precise tool movements according to the CAM program.
- Quality control: After the machining is completed, the part undergoes quality control to make sure it meets all the requirements.
CNC milling is an automated process that does not require direct human involvement in the manual processing of objects and parts. The CNC operator operates the machine using the software interface - enters the necessary data, tracks the operation of the milling machine and, if necessary, edits the entered parameters.
Finishing
It is worth adding that after CNC milling is completed, the parts can be transferred to the customer or subjected to additional processes, which can be focused on:
- Improving the smoothness of the obtained surface (e.g. CNC grinding or electropolishing),
- Improving the mechanical parameters of the surface (broadly understood electroplating, e.g. anodizing aluminum or zinc plating),
- Improving visual qualities or resistance to external factors (e.g. powder coating),
- Preparation for further processing - in cases where CNC milling is only one of the production stages (e.g. EDM).
Types of CNC milling
CNC machining itself can be performed in many planes, referred to as "axes". Typical production based on CNC milling machines takes place in 3 axes: horizontal (X), vertical (Y) and depth (Z). Such a system allows for the implementation of most standard projects. However, for more complex processes, such as those required in the automotive or aviation industries, multi-axis CNC milling machines are used, e.g. 5-axis. Thanks to the additional axes, it is possible to machine complex shapes and details in one setup, which significantly increases the precision and efficiency of production.
CNC milling can be divided into different types depending on the tool movement, cutter orientation and machine design. Here are the most important divisions:
Due to tool movement:
- Climb milling - the cutting edge of the cutter moves in the same direction as the feed of the material. This gives a smoother surface, but requires more precise machine setup.
- Conventional milling - the cutting edge of the cutter moves in the opposite direction to the feed of the material. It is more common and easier to control.
Due to cutter orientation:
- Peripheral milling - the tool removes material mainly with the side surface of the cutter.
- Face milling - the tool removes material with the end of the cutter, which allows for machining flat surfaces.
- Angle milling - the tool moves at a specific angle to the material surface.
Materials subjected to CNC milling
CNC milling is used in the processing of various materials, including:
- metals (e.g. blocks made of steel, aluminum, brass, bronze or titanium),
- plastics (e.g. blocks of various types of polymers),
- wood,
- and many other materials.
In practice, if a given material is suitable for machining with a traditional milling machine (it is "machinable"), it can also be machined using a CNC milling machine. Of course, each of these materials requires different milling parameters, the use of appropriate tools (e.g. cutters) or machining technology (e.g. additional heat dissipation).
Applications of CNC milling
CNC milling primarily supports sectors that require mass production of items that meet stringent usability standards (e.g. safety) or high visual requirements. Currently, CNC milling is used by industries such as:
- Aviation industry - for which the first CNC machine tools were created and which constantly uses this production process (both military and civilian aviation),
- Automotive industry - CNC machining is used to produce parts for most car systems, from the drive (e.g. engine blocks, pistons), through the braking system (e.g. discs, calipers), to the bodywork and interior elements,
- Renewable energy industry - uses numerical machining to manufacture elements of photovoltaic panels or windmills,
- Energy industry - mass production of energy infrastructure components would be more difficult without numerical machining,
- Medical industry - from surgical instruments to advanced prostheses,
- Military industry - commonly uses numerical machining for mass production of weapons parts, vehicles or military equipment,
- Broadly understood household appliances and RTV industry,
- Electronics industry,
- In practice, every industry that needs precise manufacturing of elements in large quantities.
Factors affecting the price of CNC milling
The cost of CNC milling is determined by many factors, which is why the valuation of each order should be carried out individually. There is no rigid price list for CNC milling - that's why you need to approach each order individually. The final price of CNC milling depends on many factors:
- Type of material being processed,
- Complexity of the project,
- Availability of ready CAD/CAM files,
- Mechanical parameters of parts,
- Expected lead time,
- Technological parameters of production,
- Order size),
- Additional services (e.g. washing parts or subjecting them to other electroplating processes).
Summary
CNC milling is a versatile and precise technology that has revolutionized manufacturing processes in many industries. Thanks to its advantages, CNC has become an indispensable tool in the production of parts with complex shapes and high dimensional tolerances. With the development of technology, CNC will play an increasingly important role in modern industry, enabling the production of increasingly advanced products.
CNC Milling - we invite you to contact us
At RADMOT, we offer CNC milling services, CNC turning services, as well as many additional services, including washing, aluminum anodizing, laser marking and assembly. We have at your disposal over 80 modern machines in our machine park, all from renowned manufacturers. Download the presentation and check on which machine tools we produce CNC turned parts and CNC milled parts.
Contact us and tell us what you need. We have been providing CNC services for almost 40 years. Our valuation is completely free. And if you're in doubt about which technology will work best for you, our expertise is at your service.
