In recent years, 3D printing technology has achieved rapid development, and many people expect that it will gradually replace CNC machining in the future, but at present, even in a few decades, it is still the main processing method for prototype manufacturing. Although 3D printing is being developed now, it still hasn’t shaken the position of CNC machining in manufacturing. Manufacturing prototypes with CNC machining in people’s minds maybe is one of the most classical ways.
In the middle of the 20th century, with the development of electronic technology, automatic information processing, data processing and the emergence of electronic computers, new concepts have been bought to automation technology. Using digital signals to control the movement of the machine tool, and its machining process has promoted the development of machine tool automation.
To use digital technology for mechanical processing was first implemented in the early 1940s by Parsons Corporation, a small aircraft industrial contractor in USA. When they manufacture the frame of the aircraft and the rotating wing of the helicopter, they use a fully digital computer to process the data of the wing processing path, and take into account the influence of the tool diameter on the processing route, so that the processing accuracy reaches ±0.0381mm (± 0.0015in), reaching the highest level at the time.
Even now, CNC still has precision that other machining methods can’t reach. Therefore, let us take a concrete look at what the advantages of CNC machining over prototype machining.
Advantages of Prototyping with CNC Machining
Stable processing quality
The accuracy and quality of the part processed by CNC are stable, and the errors of each batch of parts can also be well controlled. CNC machine tools improve the processing accuracy, and only need to enter the coordinated operation coordinates in the data lathe to process the more complex parts, It can show good results. In the process of processing, the quality stability of the prototypes has been greatly improved, the function of a single prototype is good, and the quality of the entire batch of parts is the same. In the process of operation, if you need to change other processing procedures, you can complete it with just one key operation, saving a lot of production time.
Since the precision of the CNC machine tool itself is relatively high during design, and the rigidity is relatively large during processing, the production efficiency can be 2-5 times that of ordinary machine tools by selectively using this processing technology. In the process of processing, it effectively improves the automation of the machine tool, reduces the labor intensity of the workers, and increases the benefits of the workers. At the same time, it can also bring more economic benefits to the development of the enterprise and reduce the operating cost of the enterprise.
High Precision Machining Accuracy
Numerical control digital templates and automatic processing have almost eliminated human error and achieved accuracy within 1/1000th. CNC machining tools can be automatically work according to digital instructions without manual intervention, thus eliminating errors caused by the operator. In addition, when designing and manufacturing CNC machine tools, many measures have been taken to make the mechanical parts of CNC machine tools reach higher precision.
Because CNC machining can achieve high machining accuracy, it is often used to machine functional prototypes. This is one of the reasons why other processing methods cannot replace CNC processing, and it is also the most important reason. Although 3D printing has been gaining momentum in recent years, in fact, many parts of 3D printing equipment are processed by CNC.
3D printed parts are more appearance parts, or parts that are not very demanding on assembly. Whether it is 3D printing or mold manufacturing, such as compound molds, there is a big gap compared with CNC machining accuracy.
Wide Selection of Materials
The range of materials available for CNC machining is very wide, which is another big advantage that other machining processes cannot match. Needless to say 3D printing, the diversity and stability of materials are one of the problems they face. More processing techniques like injection molding, die-casting, and vacuum casting can only process metals or plastics, even subject to many restrictions. . CNC machining is especially suitable for the finishing of non-ferrous metal parts; some non-ferrous metal parts, because of the low hardness of the material itself, and the better plasticity, it is difficult to get a bright appearance with other processing methods.
Sure, CNC machining also has certain limitations, the following are the most common CNC machining defects:
Disadvantages of Prototyping with CNC machining
The limitation of tool
Although the development of CNC machining is very mature now, and we have been working hard to reduce its own machining limitations, there are still some machining limitations that cannot be avoided. The common limitation is the limitation of CNC tools. Because the tool itself has radius, it will leave fillets in the direction parallel to the spindle of the machine tool. In addition, since the tool cannot bend during machining, if there are some covered features, CNC machining cannot process these features. Although these can sometimes be removed by electric sparks, this will leave a different machining surface.
Waste of materials
The reason why 3D printing can develop so rapidly is because it focuses on additive manufacturing and reduces material waste, which is in line with future development requirements. However, CNC machining is a subtractive manufacturing, which wastes a lot of materials, especially for some large metal shells. If you do not agree to split and process them, then they need to be removed a large piece of material, in that case, both materials and processing time have caused huge waste.
In order to solve the limitations of CNC machining, 3D printing was born on demand. However, as the most classic prototype manufacturing method, CNC still has its irreplaceable advantages. If the material performance requirements of the parts are strict, or the machining accuracy is really high, CNC is definitely the first choice for the processing method. However, if it is some appearance parts for shows, or there is no requirement for the accuracy of the parts, you can also consider more Material-saving 3D printing.