What is CNC machining? What is the basic mechanism of CNC precision machining? What are its main benefits and limitations? If you have just started this job and need to learn about it, do not hesitate to read our article below.
Article table of contents
- 1 What is the concept of CNC?
- 2 What is CNC Machining?
- 3 Precision mechanical processing
- 3.1 CAD model design
- 3.2 CNC Programming
- 3.3 Setting up the machine
- 3.4 Machining operation
- 4 Roles and basic features of CNC machining
- 4.1 Roles
- 4.2 Characteristics
- 5 Advantages and disadvantages of precision machining
- 5.1 Advantages:
- 5.2 Cons
- 6 Popular forms of precision mechanical processing
- 6.1 CNC wire cutting
- 6.2 CNC Grinding
- 6.3 Other forms of CNC mechanical processing
- 7 Materials in CNC machining
What is CNC Machining?
CNC machining, also known as precision mechanical processing by CNC machines is a mechanical manufacturing process that uses machines that apply computer numerical control technology to create products with high accuracy. It provides high accuracy with fast working speed.
CNC machining is often the final step in the production of metal parts. Or it could be the only process used to create desired mechanical products.
Since the birth of CNC technology, it has brought many great turning points in most fields and constantly improved in line with the trend of globalization.
Precision mechanical processing
Each CNC machine has different capabilities and ways of working. However, the machining process of all CNC machines includes the following basic steps:
- Design CAD models.
- CNC programming.
- Prepare the CNC machine to perform the machining operation.
CAD model design
Designing a CAD model is the first step in the precision machining process
After completing the CAD design, to proceed to machine, designs will be exported to a CNC compatible file format, such as STEP or IGES.
The CAD design file is exported to a CNC-compatible file format through CAM software. This format will generate G-code or M-code digital programming code that controls the CNC machine. Let the CNC machine perform operations, turn on, off, move, cut … to create details according to the design.
CNC programming is a lot more difficult than setting up and operating a CNC machine. To be able to program requires the programmer to understand the program code. Know how to use CNC code editing software. At the same time, you must be proficient in using one of the processing support software such as Mastercam, NX, Catia …
It is a preparatory step before running the CNC program. It includes steps:
- Attach the workpiece directly to the table.
- Install jigs, clamps JIG.
- Select the appropriate tool and install the tool on the spindle of the machine.
- Mount the necessary tools such as drill bits, milling cutters, setting the number of tools on the tool holder.
- Test the machine…
Setting up the machine is a rather complicated process. This step should also be performed by experienced engineers. To minimize errors in machining as well as optimize the production process.
Machine setup is done by experienced professionals
At this step, the CNC machine will automatically issue commands to dictate the tool and workpiece actions. Pre-set programs guide the machine throughout the machining process. To perform the necessary actions, create parts or products according to previous requirements.
The role and basic characteristics of CNC machining
Follow the general law of development. The advent of CNC technology has rapidly changed the way the entire industry is produced. All operations and machining are automated based on pre-programmed software.
It contributes to reducing the factor of dependence on the technician’s technical skills. The resulting product has great accuracy, high uniformity, and a beautiful appearance.
It also meets higher production needs. It is suitable for many different forms of machining, automation, and speeding up production. Thereby it reduces costs, improves quality, and reduces product costs.
Characteristics of CNC Machining
- High automation feature: CNC machines can all automatically perform various operations after starting up. It can automatically change the tool, correct the tool error, and check the part size. Thereby automatically correcting the relative position deviation between the tool and the part. Automatic cooling, sucking chips out of the cutting area during cutting…
- High flexibility: CNC machines can both process small, single parts and mass-produce them quickly. Most importantly, machining programming can be done outside the machine through computer equipment and various programming programs.
- The ability to concentrate work: Most CNC machines can perform a large number of different operations without changing the mounting position of the part.
- Accuracy and high-quality assurance: CNC machines with a closed control system are capable of processing precise details in both shape and size. Moreover, it helps to reduce damage caused by human error. CNC technology is also the only technology that can accurately machine parts with complex shapes such as 3-D surfaces.
- Accuracy and productivity depend on operator skill level: The entire CNC machining process can be interfered with by humans. Therefore, tolerance and machining speed depends a lot on the operator’s level and programming experience.
Advantages and disadvantages of precision machining
Indeed, the revolution of CNC machining technology has completely changed industrial production. CNC machining offers many advantages. When machining on a CNC machine, there are many utilities to mention such as:
- High precision.
- Respond quickly to market needs. Can machine many complex surfaces.
- Improve productivity especially in single-piece production of complex machined parts.
- Short machining time, high repeatability, easy mass production.
- Reduce indirect operating costs, thereby contributing to reducing production costs.
- Convenient for automating the production process.
Precision mechanical processing is considered a method to produce products with higher smoothness than other methods.
Cons of CNC Machining
CNC machining technology offers great design freedom. However, not all geometrical parts can be CNC machined. For products with complex geometries to process, it will be very expensive or impossible to manufacture.
Another limitation can be mentioned that CNC machines are not easy to operate. To program the CNC machine requires the operator to have professional knowledge and practical experience.
Popular forms of precision mechanical processing
Referring to precision mechanical processing, we refer to machining methods such as milling, turning, drilling, planning, wire cutting, electric pulse, flat grinding, round grinding, etc.
However, milling and turning are the two most common forms in machining, and precision mechanical processing today. So in fact, when it comes to CNC machining, people immediately think of CNC milling and CNC turning.
CNC Milling Process
In general, CNC milling is often used to perform complex contours on products. It is mainly used to create a complex specification of parts, such as slot, hole, and thread on the workpiece.
CNC wire cutting
EDM CNC wire cutting machining is also known as spark machining. This is a special machining method thanks to the electric spark corrosion of metal. Currently, there are 2 main wire cutting processing methods: molybdenum wire cutting and copper wire cutting.
EMD wire cutting is commonly used to process parts that cannot be machined by laser cutting
In CNC wire cutting machining by spark, the tool and the part are two electrodes. In which the detail is the Anode and the cutting wire acts as the Cathode. The motion of the cutting wire is controlled according to a contour located in the XY coordinate system through the CNC machine table.
Machining parts by wire cutting EDM is a specialized processing method for cutting metal parts with a large thickness of up to 800m. Or used for machining and cutting complex parts with narrow grooves and small holes that laser cutting or other metal cutting methods cannot do.
EMD wire cutting is also very suitable for processing simple parts with small thicknesses by stacking to save machining time and budget…
CNC grinding is a machining method that uses CNC technology to flatten or around the surface of a material.
As the name suggests, CNC grinding machines have the following main functions:
- Smooth, abrasive detail surface.
- Remove excess substances on the surface of the material.
- Polishing metal products…
CNC Grinding Machine
The introduction of CNC grinding machines contributed significantly to the development of the field of mechanical processing. Compared with the manual method, the CNC grinding method offers high precision processing.
Thereby improving product quality, developing more sophisticated industrial products limit human errors, shortening production cycles, and speeding up time to market.
Other forms of CNC mechanical processing
Materials in CNC machining
Processing a variety of materials can be considered as an important strength of CNC machining. Practically all engineering materials can be machined by CNC machines. But the most popular are still parts processed from metal and plastic.
Commonly used materials in precision mechanical processing include:
- Aluminum 6061, 7075
- Brass C360
- Magnesium AZ31
- Stainless steel 303
- Stainless Steel 316
- Carbon Steel 1045
- ABS plastic
- POM (Delrin)
Above is all the basic knowledge about CNC machining that anyone pursuing this profession needs to understand. If you have questions or need for mechanical precision, such as CNC milling, CNC turning, grinding, wire cutting CNC … Machine parts, jigs, molds, and gear … and mechanical products Main exact request please contact us.
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