Do you want to know the basics of CNC machining and its use in manufacturing? Computer numerical control (CNC) machining technology is a key part of modern manufacturing, using advanced machine tools to precisely cut, shape, and manufacture a wide range of parts.
This article will provide in-depth information about CNC technology and the basic working principles of CNC machines and their role in manufacturing a wide range of products from various industries. We will also explore the importance of relying on this technology.
Overview of CNC Machining Technology
CNC machines are computer-controlled and can produce high-precision parts. During this process, a computer program controls the movement of the cutting tool, which is controlled by software programming to remove material from the workpiece to create the finished part.
CNC technology can produce a variety of parts, including those made of metal, plastic, and other materials. The process can also produce parts with complex geometries and high precision, making it a popular choice for many industries.
It has many advantages over traditional machining methods, including higher accuracy, consistency, and speed, as well as the ability to machine complex geometries and fine details. It also allows the use of advanced cutting tools and techniques, such as multi-axis machining centers and high-speed machining, which further improves machining efficiency and quality.
History of CNC Machining
Its history dates back to the 1940s, when the first numerically controlled (CNC) machine tools were developed. Over time, these machines became more common and more sophisticated. This allowed them to meet the needs of a wide range of industries. However, older CNC machines still required manual input and had limited functionality.
The transformation of manufacturing technology began in the 1970s, when the introduction of computers led to a breakthrough: the birth of the first CNC machine tools. These advanced machines were equipped with computer control systems that could process data with unprecedented speed and accuracy. This innovation enabled CNC operators to input instructions directly to the machine tool, which then automatically performed the necessary operations, significantly streamlining the manufacturing process.
This was just the beginning of CNC machine tools and CNC machining technology, and the technology has continued to evolve over the years. The development of more advanced software and hardware, as well as the introduction of new materials and tooling options, brought more possibilities to manufacturing units. Today, CNC machinery is widely used in multiple industries, producing a wide range of products with high accuracy and precision.
How does CNC machining work?
Modern CNC systems focus on minimizing human intervention. This ensures consistent performance, which promotes smart manufacturing and delivers superior results. However, CNC manufacturing requires careful consideration from initial design to final manufacturing. The entire process is divided into three distinct steps:
Step 1: Design
The first step of CNC machining is crucial and involves software applications such as CAD, CAM, and CAE. Engineers and designers rely on these tools to design parts and products and evaluate their manufacturability. This evaluation, known as Design for Manufacturing (DFM), is critical. It ensures that the design is optimized, maximizing efficiency and reducing costs within the limitations of existing technology. In most cases, CAD tools available on the market come with internal CAM tools to facilitate pre-processing and programming. Once the CAD design is complete, the designer converts it into a CNC-compatible file format, usually STEP or IGES.
Step 2: Preprocessing and Programming
CNC machine programming primarily involves communicating with the machine using G-code and M-code. These codes, generated by the CAM software package, serve as guidelines for the cutting tool paths during CNC operation. Typically, if the design meets DFM (Design for Manufacturing) standards, the CNC machine operator does not need to intervene in the preprocessing or operation stages. However, if the design does not meet these standards, some degree of manual intervention may be required to ensure optimal performance. Preprocessing is a standard step in CNC machining, and its duration depends on the quality of the design. Writing G-code or M-code usually takes only a few minutes. However, the success of CNC programming depends on whether the design follows DFM specifications. Accurate designs produce correct code and satisfactory results, while design flaws result in incorrect code and poor results.
Step 3: Machining
The final stage is the machining process, which uses the code provided in the previous step to remove excess material from the block. Precision in machining is critical, but replicating the exact dimensions of the CAD model is often challenging. Because of this, machinists typically use ISO 2768 standard tolerances, which vary depending on industry requirements. It is a widely accepted principle that the tighter the tolerance, the higher the manufacturing cost.
Common Types of CNC Technology
CNC machining technology is a versatile process, and its operations vary depending on the specific requirements. Simple designs can be achieved with a single operation, such as milling. However, more complex designs usually require a wider variety of operations. Different CNC machining methods are usually achieved with different CNC equipment, and the following are some of the key CNC machining equipment widely used in the industry.
CNC Milling Technology
CNC milling is a high-precision, versatile machining process used to remove material from a solid block to form a specific shape or design. It requires the use of a CNC system to control a multi-point cutting tool (usually a milling cutter) with extremely high precision. During this process, the workpiece is firmly mounted on the table and the milling cutter rotates at high speed to systematically remove material. This method is particularly suitable for machining flat surfaces, but its application range goes far beyond simple shapes.
One of the main features of CNC milling machines is the ability to perform intermittent cutting through multiple machining steps to efficiently create complex geometries. The technology has evolved to include 3-axis, 4-axis, and 5-axis milling machines:
- 3 axis milling: With movement along the X, Y, and Z axes, basic operations such as drilling and planing can be achieved. This method is ideal for simple projects that require simple shapes and is popular for its simplicity. However, it has limitations in creating complex geometries, making it more suitable for less complex designs.
- 4 axis milling: With the addition of a rotary axis, more complex operations can be achieved than 3-axis milling. This method is ideal for angled cuts and more complex shapes, expanding the capabilities of CNC machining. It is particularly useful for parts that require a higher level of precision that a 3-axis milling machine cannot provide.
- 5 axis milling: This machining method is the pinnacle of CNC milling, moving along five axes simultaneously, allowing for extreme precision and complexity. In high-precision industries, it is essential for creating workpieces with tight tolerances and complex shapes. This method streamlines the production process by reducing the need for multiple setups, ensuring efficiency and accuracy.
CNC Turning
CNC turning technology is a highly efficient machining process that is primarily used to shape cylindrical workpieces, but is also suitable for processing square or hexagonal raw materials. The core of CNC turning is the use of a computer-controlled lathe to rotate the workpiece using a variety of cutting tools. These tools trim and shape the material into the desired cylindrical shape. The uniqueness of the lathe lies in its versatility and high precision, which is controlled by different spindles and speeds. The process can be performed in both vertical and horizontal settings, each of which is suitable for specific types of workpieces and machining requirements. There are two main types of machines in CNC lathe equipment:
- CNC lathe: It excels in precision turning operations and is well suited to machining high-precision cylindrical parts. It operates by rotating the workpiece relative to a fixed tool, which is ideal for machining simple to moderately complex shapes and is commonly used in the automotive and aerospace industries.
- CNC turning center: It combines turning with additional functions such as milling and drilling. This multitasking ability allows complex parts to be produced in a single setup, thereby improving efficiency and precision. It is essential for industries that require complex, multi-faceted components, such as advanced manufacturing.
CNC Drilling
Drilling is an important manufacturing process used to create threaded holes of varying sizes on a workpiece. The process is fully automated, as computers precisely control the movement and speed of the drill. CNC drilling is very common in many industries, including printed circuit boards, metal parts, and plastics. The process offers many advantages over traditional manual drilling, including greater accuracy, repeatability, and efficiency.
CNC Routing
The rough operation of a CNC router is the same as that of a milling machine. Routers typically work with softer materials, such as wood, while milling is often used for harder metals. Like any CNC operation, routers offer excellent consistency, efficiency, and accuracy. During milling, the workpiece remains completely stationary while the spindle moves in different directions. Since milling operations target softer materials, the overall spindle speed can be very low. There are many types of CNC milling machines, including benchtop milling machines, gantry milling machines, and mobile gantry milling machines. The choice of machine and cutting tool depends on the specific requirements of the workpiece and the needs of the final product.
Electrospark machining
Electrical discharge machining (EDM) is a manufacturing process that uses electrical discharge to erode material and produce complex shapes and geometries. The process works by creating a spark between an electrode and a workpiece. The machinist immerses the workpiece in a dielectric fluid that isolates the electrical energy and allows for precise control of the spark. The spark discharge vaporizes the workpiece and removes excess material to achieve the desired shape. There are two main types of EDM: sinker EDM and wire-cut EDM. Sinker EDM uses a consumable electrode to produce the spark. Wire-cut EDM, on the other hand, uses a thin metal wire that moves back and forth to produce the spark.
Different types of CNC machines
The capabilities of CNC machines vary widely, influenced by their complexity and cost. Some machines are versatile and can perform a variety of operations, while others are specialized for specific tasks. Here are the most common types of CNC machines in the industry:
- 3-, 4-, and 5-axis milling machines: These machines perform complex material removal using a variety of tools, including lathes and waterjets. Operating across multiple axes (horizontal, vertical, and tilted), these machines are capable of fine milling of wood, metal, and plastic, increasing efficiency by minimizing material repositioning.
- Lathes: The turning process involves holding the material on a rotating mechanism, usually a lathe. As the material rotates, CNC tools remove small amounts to achieve the desired shape, efficiently producing cylindrical and tapered parts with high accuracy and consistency.
- CNC routers: Designed for precision, CNC routers can cut and shape materials such as wood, plastic, and metal, enabling complex 3D designs for industries that require detailed patterns and high precision.
- EDM machines: Advanced cutting methods include sinker EDM and wire EDM. While sinker EDM uses an electrode to perform controlled hot erosion in a dielectric fluid, wire EDM uses a thin wire electrode to make intricate cuts.
CNC Machining Parameters and Xtproto’s Machining Capabilities
CNC machining is known for its precision and versatility, and is guided by parameters set during G-code generation. At Xtproto, our CNC milling systems can process parts up to 4000 x 1500 x 600 mm (157 in x 59 in x 24 in), providing a much larger build area than a 3D printer. For CNC turning, we can machine parts up to 200 mm (7.9 in) in diameter, accommodating a wide range of component sizes. Our CNC machines are capable of exceptional accuracy, with tolerances as tight as ±0.001 in (±0.025 mm), which is less than half the diameter of an average human hair. Xtproto can meet your needs with a typical delivery time of 5 working days and simple parts can be delivered within 1 day. We are committed to providing precise and efficient services.
3D printing can break through the key design limitations of CNC machined parts with complex geometries
When designing CNC machined parts with complex geometries, understanding the limitations of the machining process is critical to achieving the desired results. 3D printing can produce complex shapes without significantly increasing costs, unlike CNC machining, where increased part complexity leads to higher CNC machining costs due to additional setup and machining steps. The main limitation stems from the geometry of the cutting tools, which are usually cylindrical and have difficulty achieving sharp internal corners due to cutting length restrictions.
Another key factor is tool accessibility. Three-axis machines can only machine features that are directly accessible from above, while five-axis systems provide greater flexibility by allowing the tool and part to move at multiple angles. This capability makes it possible to machine areas that would otherwise be inaccessible to three-axis systems. Thin-walled parts are also challenging because they are susceptible to vibration and may break under the effects of machining forces. Considering these limitations when designing your CNC machining ensures that your parts are both manufacturable and high quality.
Xtproto is the Right Manufacturing Partner for Every CNC Project
For small and medium-sized businesses, meeting CNC manufacturing needs can be resource-intensive and requires expertise in both part machining and CNC certification. To meet these challenges, partnering with a professional CNC machining provider like Xtproto has become a common industry practice. Xtproto is the ideal manufacturing partner to provide top-notch CNC machining services. The company is headquartered in China, a global manufacturing hub, and has an excellent track record. Able to achieve tolerances as precise as 0.01 mm, Xtproto’s team of experts offers a range of services including CNC Turning Services, CNC Milling Services, Sheet Metal Production Services.
In addition, Xtproto is not only ISO 9001 certified, but also has advanced quality control processes to ensure that every project meets the highest standards of customer satisfaction. The combination of expertise and quality assurance makes it a reliable choice for a variety of CNC machining needs. Get started on your CNC project today! With cutting-edge technology and expert craftsmanship, we turn your innovative designs into reality.
Conclusion
CNC machining is a cornerstone of modern industry, sparking curiosity among those in and outside the industry. It is a key driver of the industrial age and will play a major role in the future. The rise of smart factories and Industry 4.0 depends on CNC machining capabilities. This technology combines manual machining with digital control, ensuring unparalleled precision and consistency. Although this manufacturing technology has some limitations, its advantages far outweigh the challenges. As the technology develops, current issues are expected to be resolved, further enhancing its impact. Want to experience top-notch CNC machining results? Contact Xtproto today to explore the excellence of advanced CNC solutions!