What is the difference between 3D printing and CNC?

When quoting the prototype project, it is necessary to choose the appropriate processing method according to the characteristics of the parts in order to complete the prototype project faster and better.At present, hand-board processing mainly includes CNC machining, 3D printing, laminating, rapid tooling and so on.Today we will talk about the difference between CNC machining and 3D printing.

First of all, 3D printing is an additive technology, and CNC machining is a subtractive technology, so they are very different in terms of materials.

1. difference in material

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 (DFM), 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 all piece by piece plates, that is, plate-shaped materials. After measuring the length, width, height + loss of parts, the plates of corresponding sizes are cut for processing.CNC machining materials have more choices than 3D printing. General hardware and plastic plates can be processed by CNC machining, and the density of formed parts is better than that of 3D printing.

2. Differences in parts due to molding principles

As we mentioned earlier, 3D printing is a kind of additive manufacturing. Its principle is to cut the model into N layers/N multi-points, and then pile them up layer by layer/little by little in order, just like building blocks Same.Therefore, 3D printing can effectively process and produce parts with complex structures, such as hollow parts, while CNC is difficult to process hollow parts.

CNC machining is subtractive manufacturing, through various high-speed cutting tools, cutting out the required parts according to the programmed cutting path.Therefore, CNC machining can only process rounded corners with a certain radian, but cannot directly process inner right angles. It must be realized by wire cutting/sparking and other processes.Outside right angle CNC machining is no problem.Therefore, parts with inner right angles can be considered for 3D printing processing.

There is also the curved surface. If the part has a large surface area, it is recommended to choose 3D printing. CNC machining the curved surface is time-consuming, and if the programming and operator experience is not enough, it is easy to leave obvious lines on the part.

3. Differences in operating software

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.

CNC programming software is much more complicated, and requires professionals to operate, and people with zero foundation generally need to learn it for 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. 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.

There is a sequence of hearing, and there is a specialization in the art industry.CNC machining and 3D printing each have their own advantages and disadvantages.Choosing the right processing technology plays a vital role in your prototype project.Choose Yecheng, our engineers will analyze and suggest your project.