The difference between CNC and 3D printing

In recent years, 3D printing has been widely used in various industries, so compared with CNC processing, what is the difference between the two? First of all, the nature of processing is different. 3D printing is an additive technology, while CNC machining is a subtractive technology, that is, 3D printing is addition, while CNC machining is subtraction. Below, Jiahangaero sorts out some of the differences between the two.

• 1 Differences in materials

3D printing materials mainly include liquid resin (SLA), nylon powder (SLS), metal powder (SLM), gypsum powder (full-color printing), sandstone powder (full-color printing), wire (FDM), sheet (LOM) etc. Liquid resin, nylon powder and metal powder occupy most of the market for industrial 3D printing.

The materials used for CNC machining are strip-shaped and plate-shaped materials. By calculating the volume of the finished product, the raw materials of the corresponding size are cut for processing. CNC machining materials have more choices than 3D printing, including but not limited to: aluminum, copper, iron, steel, plastics, etc. Different materials can be processed and manufactured through different CNC lathes and tools. Therefore, if you need to produce metal parts, you can only choose CNC processing.

• 2 Differences in parts caused by different forming principles

As we mentioned earlier, 3D printing is a kind of additive manufacturing. Its principle is to recognize the model into multiple layers, each layer has multiple points, and then form a layer with points and points in sequence, and the layers and layers form a model, similar to building Building Blocks. Therefore, 3D printing can effectively process and produce parts with complex structures, such as hollowed out parts, while it is difficult for CNC to realize hollowed out parts.

CNC machining is subtractive manufacturing. Through various high-speed cutting tools, according to the program setting, the tool path cuts the material to form the required parts. In terms of tolerance, CNC machining is usually between 0.1-0.001mm, while the tolerance of 3D printing is between 0.5-0.1mm, so when high-precision parts are required, CNC machining is the best choice.

• 3 Difficulty of operation

Most of the slicing software for 3D printing is easy to operate, and even a layman can proficiently operate the slicing software within a day or two of professional guidance. Because the slicing software is currently optimized very simply, supports can be automatically generated, which is why 3D printing can be popularized to individual users.

From CNC machining design to programming, cutting tools, etc., programming and other operations are more complicated and require professionals to operate. People with zero foundation generally need to learn about half a year. In addition, a CNC operator is needed to operate the CNC machine. Because the programming is very complicated, a part can have many kinds of CNC processing schemes, while 3D printing will only have a small impact on the processing time and consumables because of the placement position, which is relatively objective.

• 4 Production cycle

In terms of production efficiency, a simple comparison cannot be made between the two, because CNC machining is usually some metal products, and is affected by tolerances, and sometimes it is even necessary to slow down the cutting speed to match the corresponding tolerances. Generally speaking, 3D printing is much higher than CNC processing in terms of production cycle and output efficiency.

• 5 Differences in post-processing

There are not many post-processing options for 3D printed parts, usually grinding, oil spraying, deburring, dyeing and so on. There are various post-processing options for CNC machined parts, in addition to grinding, oil injection, deburring, electroplating, silk screen printing, pad printing, metal oxidation, laser engraving, sandblasting and so on.

At present, 3D printing technology has initially demonstrated its role. It has high efficiency, short production cycle and low cost, but its low precision and few applicable materials are also very obvious shortcomings. We need to know that 3D printing cannot be seen in metal product parts, especially in aviation and military parts, which require very high precision. Jiahangaero believes that the emergence of a new object and new technology must be positive, and giving them enough time to develop will definitely bring positive feedback to the society. But for now, if you need high-precision metal products, such as aluminum alloy precision machining and manufacturing, then CNC machining is your best choice. Jiahangaero specializes in aluminum alloy precision machining and manufacturing, and the tolerance can be controlled at 0.001mm. Welcome to contact us.