Metal milling with computer numerical control (CNC) equipment is now a standard process for manufacturing parts for companies in many industries that demand high precision and repeatability. This form of machining combines traditional milling with computer numerical control technology, which makes it possible to produce virtually identical parts in a very short time. CNC milling of metal and other materials allows complex parts to be formed from a single block of material, including making grooves, threads or gears. What is CNC milling and how has it revolutionized almost every area of manufacturing?
CNC Milling – what is it?
CNC milling ("computerized numerical control") is one type of machining that allows for the rapid formation of flat and shaped metal surfaces. It is a production method that combines traditional metalworking methods (removal of excess material with a manually guided cutter - milling is a cavity method) with numerical control technology, thanks to which the entire process is automated.
How does CNC milling itself look like?
A milling cutter seated in a spindle (which is part of a milling center) gradually removes the top layer of a semi-finished product (excess material) to obtain the required size and shape. The movements of the milling head are controlled by a CNC controller, executing a preset sequence of movements in at least one plane, with parameters (e.g. depth of cut, speed of rotation or feed) specified in the program, adapted to the parameters of the workpiece and the expected surface quality.
Thanks to the use of computer control (the movements of the cutter are controlled in many planes by actuators and relays) and the possibility of automating the process of insertion and removal of machined workpieces into the working space of the CNC milling machine, it is possible:
- very fast and repeatable production of large quantities of parts (especially compared to traditional manufacturing methods),
- lower unit cost of manufacturing parts - especially evident in larger projects,
- maintenance of marginal tolerances between parts made in a single batch, and even between batches,
- improved occupational safety,
- reducing the 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 more CNC machines (in the case of traditional milling machines - one person can work on one machine within a certain time frame).
In practice, if a material is suitable for processing with a traditional milling machine (it is "machinable"), it can also be processed with a CNC milling machine. Of course, each of these materials requires different milling parameters, the use of other tools (e.g., milling cutters) or machining technology (e.g., additional temperature dissipation).However, these are issues that are the responsibility of specialists involved in the valuation or implementation of CNC milling projects.
If you need a quote for CNC machining services - contact RADMOT.
CNC milling - what is the machining process like?
The CNC milling process combines traditional machining (removing excess material with cutters) with computer control. In a nutshell, CNC milling is implemented in several steps:
- the design of the part must be made in the form of a three-dimensional model (in CAD software - computer assisted design) - whether from scratch or based on a traditional technical drawing. This is the basis for further work and a very important part of the CNC machining order,
- on the basis of the CAD file, the specialist who prepares the work of CNC machines creates a program (project) in a form understandable for the cutting machine (in this case - CNC milling machine) - properly formatted CAM (computer aided manufacturing) file. For this it uses software compatible with the equipment used (using G-code),
- the file prepared in this way is uploaded to the controller of the milling machine or other CNC equipment, tested and - after making sure that it implements the whole process correctly - machine operation is started, that is, the execution of the order is started.
CNC milling is an automated process that does not require direct human involvement in the manual processing of workpieces and parts. The CNC operator operates the machine through a software interface - entering the necessary data, tracking the milling machine's operation and editing the entered parameters if necessary. It is worth mentioning that after CNC milling is completed, parts can be handed over to the contractor 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 galvanotechnique, such as aluminum anodizing or galvanizing),
- improvement of 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 stages of production (e.g. EDM).
CNC machining itself can be implemented in multiple planes, referred to as "axes."
Typical production based on CNC milling machines is realized in 3 axes (horizontal, vertical, depth), but many industries require more complex processes (e.g., automotive), where multi-axis CNC milling machines (e.g., 5-axis) are used.
The origins and development of CNC milling
CNC milling and numerical control technology has its origins in the 1950s. It was developed in response to the U.S. military aviation's demand for the development of jet aircraft and the need to produce semi-finished products with identical properties. Production was to be mass, fast and without human input to minimize the risk of errors.
The first numerically controlled machine was created by the Massachusetts Institute of Technology, a respected technical college in the US. The first NC (numerically controlled) milling machine executed programs entered into the computer using punch cards. Over time, the development of microcomputers accelerated and they also began to be used in computer numerical control (CNC, from computer numerical control) machine tools. Today CNC cutting machines are used in practice in every manufacturing industry.
Types of CNC milling
There are several different types of CNC milling because of the type of milling machine and the way the blades work.
Due to the arrangement of the blades, we distinguish:
- cylindrical (circumferential) milling, which produces 2 planes simultaneously,
- Face milling, during which the axis of the cutter is located perpendicular to the machined surface,
- oblique milling, during which the axis of the cutter in relation to the machined surface forms a different angle from 0-90.
With regard to the construction of the milling machine, we distinguish:
- full milling (three-sided) - as many as 3 machined surfaces are formed,
- incomplete milling (two-sided) - 2 machined surfaces are formed,
- free milling (one-sided) - 1 machined surface is produced.
With regard to the movement of the milling machine, we distinguish:
- concurrent milling, where the cutting edge advances in line with the feed of the material,
- counter-rotating milling, where the cutting edge moves opposite to the feed of the material.
What are the advantages of CNC milling?
Today, it is difficult to imagine metalworking without computer-controlled milling technology. The key advantages of CNC milling technology are:
High production repeatability
Appropriately calibrated CNC machines tools allow the production of parts with virtually identical dimensions, while maintaining very tight tolerances (less than 0.05 mm).This makes it easy to replace parts manufactured with this technology or combine them into larger assemblies, and in addition, rejects at the stage of quality control are noticeably smaller (with proper calibration of machine tools).
Precision manufacturing and product durability
CNC milling makes it possible to produce precise grooves, even for parts with complex surfaces. Combined with the repeatability of this production, this translates into greater product reliability and longer product life.
Manufacturing speed
CNC milling is a fully automated process, which translates into significantly faster production of larger batches of parts. However, it should be remembered that the preparation of the CNC machining process is more time-consuming than creating templates to work with traditional milling machines - which is why this technology works better for the production of large batches of parts.
Worker safety
Automation of milling makes human work not only lighter, but above all safer. CNC milling machines do not require constant supervision, thanks to which one specialist is able to supervise processes carried out simultaneously in multiple cutting centers.
Lower production costs
Due to the automated nature of the work and (in practice) the ability to produce around the clock, CNC machining is more profitable, especially for larger batches of parts. However, these savings can only be seen when producing larger batches of parts - CNC technology was developed for such production.
What challenges does CNC milling present?
CNC milling, in addition to its undoubted advantages, also presents new challenges for the service industry. Today, metalworking requires highly specialized knowledge, and the production process itself is the result of coordinated cooperation between many departments, such as:
- quality control,
- modern measurement systems,
- maintenance and the use of failure prevention methods,
- production process design technology.
At the same time, the expectations of customers of metalworking services are increasing.
This necessitates the continuous development of the machine park of companies engaged in numerical control-based manufacturing (such as RADMOT). In addition, the introduction of artificial intelligence in the CNC machining industry opens up new opportunities to optimize production processes, reduce costs or achieve even higher production quality.
What industries use CNC milling?
CNC milling primarily supports sectors that require mass production of items that meet stringent usability standards (e.g., environmental, safety) or high visual requirements. Currently, CNC milling is used by industries such as:
- aerospace industry - for which the first CNC machine tools were developed and which constantly uses this production process (both military and civil aviation),
- automotive industry - CNC milling is used to produce parts of most car systems, from powertrain (e.g. engine blocks, pistons), through brake (e.g. discs, calipers), to body or interior components,
- renewable energy industry - uses numerical machining to manufacture components for photovoltaic panels or windmills,
- energy industry - mass production of energy infrastructure components would be more difficult without numerical cutting,
- medical industry - from surgical instruments to advanced prostheses,
- the military industry - commonly uses numerical cutting to mass produce parts for weapons, vehicles or military equipment,
- the broad household appliances and consumer electronics industry,
- the electronics industry,
- in practice, any industry that needs precision manufacturing of parts in large quantities.
What does the price of CNC milling depend on?
How much CNC milling costs is determined by many factors, so the valuation of each order should be carried out individually. There is no rigid price list for CNC milling - that is why RADMOT specialists approach each order individually.
The final price of CNC milling depends on many factors:
- the type of material to be processed,
- complexity of the project,
- availability of ready CAD/CAM files,
- mechanical parameters of the part,
- expected turnaround time (cito orders are usually more expensive),
- technological parameters of production (e.g. length of milling line),
- the size of the order (it is worth adding that the minimum order for CNC milling that we accept at RADMOT is 100 parts per batch; below that, the profitability of such a project may not be satisfactory for the customer),
- additional services (such as washing parts or subjecting them to other electroplating processes).
Therefore, at RADMOT, we price cooperation only after we know the customer's expectations, in order to give him a clear and certain answer.
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.
