When quoting for a prototype project, it is necessary to select the appropriate processing method based on the characteristics of the components to complete the project faster and better. Currently, prototype processing mainly includes CNC machining, 3D printing, laminating, rapid tooling, and so on. Today, we will discuss the differences between CNC machining and 3D printing.
Firstly, 3D printing is an additive technology, while CNC machining is a subtractive technology, so they differ greatly in terms of materials.
1. Differences in materials
The main materials for 3D printing include liquid resin (SLA), nylon powder (SLS), metal powder (SLM), gypsum powder (full-color printing), sandstone powder (full-color printing), wire material (DFM), sheet material (LOM), and so on. Liquid resin, nylon powder, and metal powder account for the vast majority of the industrial 3D printing market.
The materials used for CNC machining are all plate-like materials, which are measured for length, width, height, and wear, and then cut into corresponding sizes for processing. CNC machining offers a wider range of material options than 3D printing. Generally, both metal and plastic plates can be processed using CNC machining, and the density of the molded parts is better than that of 3D printing.
2. Part differences caused by molding principles
As we mentioned earlier, 3D printing is a form of additive manufacturing. Its principle involves slicing a model into N layers/N points, and then stacking them one by one/point by point in order, just like building blocks. Therefore, 3D printing can effectively process and produce parts with complex structures, such as hollow parts, which are difficult to process using CNC.
CNC machining is a subtractive manufacturing process that uses various high-speed rotating tools to cut out the required parts according to programmed tool paths. Therefore, CNC machining can only produce rounded corners with a certain degree of curvature, and cannot directly produce internal right angles, which need to be achieved through processes such as wire cutting/sparking. External right angles can be machined by CNC without any issues. Therefore, for parts with internal right angles, 3D printing can be considered as an alternative production method.
Another point is about curved surfaces. If the part has a large curved surface area, it is also recommended to choose 3D printing. CNC machining of curved surfaces is time-consuming, and if the programming and operator are not experienced enough, it is easy to leave obvious patterns on the parts.
3. Differences in operating software
Most 3D printing slicing software is easy to operate. Even laymen can become proficient in operating slicing software after a day or two of professional guidance. This is because slicing software has been optimized to be very simple, and supports can be automatically generated, which is why 3D printing has become popular among individual users.
CNC programming software is much more complex and requires professionals to operate. For those with no foundation, it usually takes about half a year to learn. Additionally, a CNC operator is needed to operate the CNC machine.
Because programming is highly complex, a single component can have numerous CNC machining options. In contrast, 3D printing only experiences a minor impact on machining time and material consumption due to placement, which is relatively objective.
4. Differences in post-processing
There are not many post-processing options for 3D printed parts, which generally include grinding, oil spraying, deburring, dyeing, and so on.
The post-processing options for CNC machined parts are diverse. Besides grinding, oil spraying, and deburring, there are also electroplating, silk screening, pad printing, metal oxidation, laser engraving, sandblasting, and more.
Different people have different learning paths, and different fields have their own specializations. CNC machining and 3D printing each have their own advantages and disadvantages. Choosing the right processing technology has a crucial impact on your prototype project. Choose Qile, and our engineers will analyze and provide suggestions for your project.