What Is CNC Machining? A Complete Guide For You.

CNC machining is a modern process by which computers control machines that shape materials with high precision. An article is provided on what its process is, and on the materials used, its precision, its advantages and how to choose a CNC machining shop. This guide is very informative for beginners as well as experts in CNC machining.

Table of Contents

What is CNC machining?

CNC machining or computer numerical control machining is a manufacturing process. It was controlled by a computer to shape and cut materials like metals, plastics, and wood with very much accuracy and precision. The technology automatically operates machine tools for the creation of accurate and repeated components and parts on demand.

CNC machining process

CNC milling:

Milling involves using a rotating cutter that cuts away material from a workpiece to produce different shapes, slots, and other features required. A variety of movement is possible on different axes enabling the production of intricate parts. It is employed in most aerospace and car manufacturing companies to develop complex components of superior accuracy.

CNC drilling: 

The drilling is mostly of CNC operations concentrated on making holes into workpieces. This is an intrusion done using a revolving drill which carves a hole with a particular width. Accurate hole placement and size consistency are extremely important for manufacturing.

CNC turning:

Cylindrical parts are cut using turnings which involves revolving of work pieces while moving the cutting tools in or out of them. The procedure may be used in manufacturing of these kinds of products such as shafts, bolts, and pins. It is essential in the manufacture of rotational symmetry parts due to its precision in dimension and surface quality.

CNC grinding:

Precision machining, known as grinding is used to fine surfaces and very close tolerances. This process entails working with abrasives which eliminate fine particles but leave the surfaces very smooth and accurate. In certain cases where surface quality plus dimensional fidelity is necessary; for example, in the use of medical optics, grinding becomes essential.

CNC machining materials

Materials that are used in CNC machining can be grouped as metallic, plastic, ceramic, or composite.

CNC machining metal materials

The metal materials consist of steel, aluminum alloys, and brass. The strength of steel gives it wear resistance while aluminum alloys are lightweight and resist corrosion hence suitable in aerospace and automotive industries respectively. Because of such features as electric conductivity, brass is widely employed in electronics, pipes, etc.

CNC machining plastic materials

These plastic materials consist of polypropylene, PVC, and polystyrene. The material used for packaging and manufacturing parts is usually polypropylene, which is light and does not corrode. Polystyrene is useful in packaging and polystyrene while PVC is good in wiring and piping because of its insulating qualities.

CNC machining composite materials

Unique composite materials like carbon fiber composites, fiberglass composites, and Kevlar. These include carbon fiber composites that are mainly used for aerospace and automotive engineering. Shipbuilding and structure construction uses fiberglass composites. It is an affordable option that can be easily procured at a low price. On the other hand, high-strength Kevlar is widely applied in military and personal safety.

CNC machining ceramic materials

There are special types of ceramic materials such as aluminum oxide and silicon nitride ceramics. Some of the aluminum oxide ceramics have strong resistance to corrosion and high temperature which are useful for electronic ceramics and ceramic knives. High-temperature silicon nitride ceramics offer efficient insulation and are applied in heat sinks. There are common materials used in CNC machining with different advantages and applications.

CNC machining surface finishing

Good surface finishing is crucial to CNC machining. It makes parts look good and helps them remain accurate in size. It enhances function through minimization of rubbing as well as high wear resistance. It also provides corrosion protection. Smooth surfaces reduce potential hazards. The reality is that surface finishing improves both aesthetics and performance thereby increasing parts lifetime.

The common type of surface treatment

  • Polishing: It includes brushing in order to produce a glossy and polished appearance that is mainly applied to the embellishment elements of a design.
  • Anodizing: A process of electrochemistry that produces a decorative metallic film on metals like aluminum, increasing their corrosion protection and appearance.
  • Passivation: Removal of surface contamination and enhance corrosion resistance by using stainless steel.
  • Painting or Powder Coating: It protects from environmental elements in addition to adding color.
  • Electroplating: A procedure to plate the part with a layer of metal which is an enhancement for the look and reducing corrosion.
  • Blasting: Imperfections and irregularities are cut off with abrasive materials resulting in an uneven surface.
  • Laser Engraving: This is used to ensure accuracy when marking or stamping.
  • Chemical Treatments: Other surface modification methods include etching and blackening that involve some types of chemical processes.

CNC machining tools

CNC machining is a precise manufacturing process that uses various tools to remove material from a workpiece. Here are some common CNC machining tool types.

CNC cutting Tools

Inserts: Milling, turning and drilling tools have replaceable cutting tips known as inserts. Cutting implements are available in various geometric forms and compositional materials for different type of cutting needs.

End Mills: They involve multi-functional blades having many uses. These tools have cutting edges at the bottom and on the sides for milling, contouring, slotting, and pocketing.

Ball Nose End Mills: They create raised surfaces that are used for profiling as well as contouring. These have round ends so that they can create clean-cut.

CNC surface Finishing Tools

Face Mills: Face mills are used in facing and squaring the surface of a workpiece. Multiple inserts facilitate this material and improve its efficiency of removal.

Reamers: Reamers are employed to enhance the precision and surface finish of holes. They generally serve as control devices by checking on their precision immediately after drilling.

Boring Bars: The boring bars are used for expanding the existing hole or fabrication of internal features with high accuracy.

CNC hole Machining Tools

Drills: Drills allow CNC machines to cut workpieces into holes. There exist different drills like twist drill, center drill, position drill, etc., for application in different activities.

Taps: Holes are taped using taps. Threads are of varied thread size and type to be able to make threads on different materials.

Countersinks and Counterbores: These include countersinks and counterbores for recessing various forms of fasteners like screws and bolts.

CNC machining specialty Tools

Knurling Tools: Knurling implements involve the development of patterns on the surface of a workpiece to provide better hold.

Broaches: Tools for broaching are used on such workpieces as key ways, splines, etc, which require the making of special shapes or more complicated patterns.

Grooving Tools: They are used for making O-ring grooves or circlips.

CNC machining accuracy and precision

The machine control tolerance usually falls between 0.005 and 0.001 mm for CNC machining precision. This high degree of accuracy is only possible via issues such as machine calibration, tool quality, and vibration control handled with great care.

Generally, the accuracy of CNC machining is aimed at achieving a result deviating not more than 0.05 mm from the initial layout. In order to attain such accuracy, you require detailed programming to program your CNC machine for the job; optimize tool path, and know materials and their properties. Precision and accuracy should be struck at precise tolerances in order to fulfill the industry standard requirements efficiently.

The advantages of CNC machining

Precision and Repetition

It is firstly widely known for its highly precise and repetitive nature that makes it unique compared to any other machining equipment. Using a CNC system, it is possible to control and move machine tools precisely and achieve accuracy of measurement on the micron level, guaranteeing every finished product attains high-quality parameters. Moreover, CNC technology is superior at providing uniform repeatability of different products, thereby minimizing product variability and increasing the reliability of the system.

Handling Complex Geometric Shapes

Besides that, it is important to mention that CNC machining is distinguished for dealing with complicated geometrical shapes. The flexible control allows the CNC machine tools to cut complicated shapes like spirals, curves, grooves, and even boreholes. This ability enables designers to have more flexibility in product creation even without worrying about machining complications.

Automated Production

Thirdly, CNC systems’ automation features enhance cost reduction and efficiency. Modern production requires automated execution of such operations as cutting, milling, or drilling by means of CNC machine tools thus minimizing the labor. It improves production efficiency while at the same time decreasing labor cost hence increasing the economics of the manufacturing process.

Material Diversity

In addition, CNC machining is also versatile and can work well with different types of materials such as metal, plastic, wood, and composites among others. Such diversity enables a widespread field of applications for various sectors ranging from aerospace to medical devices manufacturing.

Quick Production Changes

Finally, CNC systems provide a fast changeover, which in turn enables adjustment to the production needs of other products. It is enough to change machining programs in order to quickly move on to another manufacturing of components or products and reduce lost production time while achieving the highest level of production effectiveness and flexibility.

Reducing Human Errors

Lastly, CNC machining reduces the chances of human errors. It has an automated nature thus it involves very minimal operator action hence minimizing the risks that might be associated with manual operations. It increases product quality and reliability thus reducing scrap and gives great benefits to these firms. Briefly, the advantages of CNC machining in production include high accuracy, automation, and increased efficiency and quality of manufactured products.

Comparison of CNC machining and conventional machining

Whereas automation has characterized CNC machine which is governed by computerized instructions, in cutting-cutting tools. Such a technique ensures that there is accuracy, consistent outcomes as well as limited errors by man. Conversely, traditional machining is directly operated by humans and its success depends on individual differences.

The strengths of CNC machining lie in the fast speed, precision, and repeatability. The product can generate complicated parts with close tolerances therefore it is suitable for mass production. Further, it eliminates the requirements of well-trained machinists and therefore, minimizes labor costs.

Though less costly, conventional machining entails a lot of hard work and can be adjusted to suit different tasks. This is more preferred as a prototype or single-piece component due to skilled machinists who can give real-time changes. In addition, it could prove more economical in the case of small-volume productions.

CNC machining applications

A wide variety of industries employ CNC as a technology. It finds applications in critical areas such as aerospace and automotive, as well as in sensitive domains such as medicine and electronics. Specifically, CNC machining provides excellent accuracy and flexibility thereby making it an ideal option in manufacturing parts with complex designs, prototypes, or components.

The essence is that CNC machining forms the backbone of today’s manufacturing operations whereby it guarantees ease and precision in the fabrication of crucial parts. Nowadays in modern industrial society this technology is very important because of increased need for complex parts.

The main steps of CNC machining work


CAD Model: The first step is to develop an accurate CAD model of a part that requires machining. This part is designed with the use of CAD software which describes the dimensions, shape, etc. It is a digital model on which all the actions of machining are based.


G-code Generation: The next thing will be to develop G-code instructions after the CAD model is prepared. CNC machines understand G-code. These are nothing short of a simple series of commands that direct the machine on its way to cut through and carry out different exercises, as mentioned, on the workpiece. The G-code is usually created by CAM (Computer-Aided Manufacturing) software that translates the CAD model into a series of accurate machining commands.


Workpiece Preparation: The CNC machine and workpiece should be set up before machining starts. It entails clamping the workpiece on the worktable. The workpiece must have the correct orientation and be properly positioned. It must also be locked in place before machining by means of clamps or fixtures.

Loading CNC Program: This is then loaded into the controller of the CNC machine that reads this program in the form of G-code. However, this is an important step because the machine will use the instructions given in the program to perform the machining process. One must check that the appropriate program is loaded to prevent mistakes.


Precise Operations: The process starts when the workpiece has been set up firmly and the CNC program has already been loaded. It is a cutting tool that does precise cutting, drilling, and shaping operations on the material via the CNC machine. This is a computerized system that takes its commands from the G code and cuts to the precise dimension and shape specified in the CAD.

Monitoring: Usually, the operators monitor the progress of the machine during machining to ensure that all is fine. They can, therefore, fine-tune the machine if the need arises and improve the precision and quality of the machined part.

Quality Control: After the machining process has ended, an inspection of the accurate and high-quality machined part is conducted. At this stage, any finishing touch to bring it up to standard may also be done.

CNC machining cost

CNC machining per hourly

The costs of CNC machining are varied by location and complexity relating to the machining process. While the European continent‘s average cost is $35-120 per hour, in Chinese CNC machine shops this value is much more competitive and equals $10-30, the price varies depending on the number of axes involved as well. For Including the cost discrepancy in various regions It is a price difference often associated with diverse lab costs and other operating expenses..

CNC Machining Cost Factors

However, in certain instances, CNC machining costs do vary a great deal depending on where one is located as well as the complexity of the cutting process. For instance, a European average ranges from $35 to $120 per hour, whereas Chinese CNC machine shops offer as low as $10- $30 per hour which is also dependent on the number of axes. The varied cost is mostly occasioned by varied labor and operational costs in different regions.

The costs of CNC machining largely vary depending on multiple major considerations. The cost of different materials also goes a long way to determine how much one spends on a particular building or project. Another factor that influences prices is how complicated it is to set up a machine and pay workers. Costs are based on other factors such as machining times, tooling, precision requirements, and batch sizes.

Optimizing CNC Costs

Having efficient machines set up and effective skilled labor management would also assist in controlling the cost. Striking a delicate balance between accuracy and budget considerations may be facilitated by optimizing batch size in turn, which could result in cost savings. Including overhead and facility costs into the pricing structure makes sure that operating expenses for everything will be paid off, thus helping with economic concerns.

How to choose a CNC machining shop?

In order to select an appropriate CNC machine shop for your part-machining requirement, you should determine your project specifications, such as the kind of input material(s), tolerance limit, as well as quantity of expected parts produced within the stipulated time cycle (Michalek Next, assess the quality, equipment, experience and specialist fields that each candidate machine shop has in order to determine if it is able to satisfy you.

Practicalities like price, delivery time, location, customer service, reviews, and environmental policies should be considered when purchasing clothes online. Lastly, meticulously read through the contents of the contract and sign it only when you pick the best machine shop. By adopting these measures you have assured yourself of selecting a first-class CNC machine shop that will go through for your needs.


CNC machining is an automated and very accurate process of manufacturing which used in different industries. This provides advantages that include precision, the complexity of shape handling, material variety as well and cost-effective. Thus, when opting for a CNC machine shop it is vital to take into account such project specifications as quality, price, and other practical factors.


On-demand CNC Machining prototyping and parts with Custom Finishes and low volume manufacturing.

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