Posted on: Feb 8, 2018, | By Steve, WayKen Project Manager
CNC is short for Computer Numerical Control, which is a manufacturing process in which programmed computer software dictates the movement of corresponding tools and machinery, which carry out the dimensional tasks as specified, much like a robot. There are many kinds of CNC machines, such as milling, lathe, turning, drilling, and tapping etc.
Both CNC and 3D printing are very popular methods in rapid prototyping when choosing between CNC and 3D printing, there are a few simple guidelines that can be applied to the decision making process.
- CNC offers greater dimensional accuracy and stability, producing parts with better mechanical properties, if tight clearances are required, the critical dimensions can be 3D printed oversized and then machined during post-processing.
- The parts are always come out with smooth surface from CNC machining, while it is very rough from 3D printing;
- Material selection is very limited for 3D printing. Usually only photosensitive material for SLA process, and PA12 for SLS. But CNC machining, you can use any engineering material, such as ABS, PMMA, POM, Aluminum, Magnesium, etc;
- Due to the material, there are not too many post finish options for 3D printed parts; while you can use almost any kind of finish as you like according different material for CNC machining;
- As for low volume production, CNC is more cost-effective than 3D printing.
Accuracy would be the most valuable feature for CNC machining, so how do we control the dimension during the process?
- Choose a high precision machine. With the improvement of product design requirements and the development of high-speed and high-precision machining technology, the quality of parts, the processing speed and procedures have been greatly improved.
- Use suitable chuck holders. With the use of machining center, also rendered the relevant tools upgraded. In particular, the quality of the tool on the CNC machining, the impact of the shank will become prominent. In the rotary tool processing system, in order to ensure the realization of tooling performance, it’s a must to keep the tight connection between chuck and machine.
- Use a suitable cutting tool. Proper use and choice of tool would be an important factor affecting the quality of CNC machining. Carbide cutting tools are more and more widely used, high-speed processing of cemented carbide coating will replace most of the steel front tool, including reamers, ball-end knives, boning knives and other simple tools, carbide coating will be at high-speed Processing tool materials play an important role, applied to most of the conventional processing areas.
- CNC process program. In the high-speed and high-precision machining process numerical control program design is mentioned the importance of the importance of the whole process must be controlled, any errors will have a serious impact on the quality of the parts, the process will be on the quality of the program To a decisive role. CNC machining process design can be considered from the rough parts to the shape of a part of the processing process between the state of the control program. Good process plan throughout the design process is more difficult, need to go through the practice of summary and modification can be obtained in the design process to be considered along with much information, the relationship between the information and extremely intricate, which must be relied on the experience of the operator. Therefore, the quality of the design process scheme depends mainly on the experience and level of technical staff.
- Pre-programmed software. A good software can also improve mold processing quality and efficiency, which is a great supplement of CNC machining. Anyway, the software itself is just a tool, a good engineer with rich experience in both program and operating would be an essential role.
- Operator. Machining center operator is the implementation of CNC machining; their control of CNC machining quality is also very obvious. They know the real-time status of machine tools, shanks, tools, tooling, software and cutting parameters while performing machining tasks. Each of their operations has the most direct effect on CNC machining, so the machining center operator's skills and responsibilities Heart are also to improve the quality of CNC machining key factors!
Above all, you can see, as one of the most popular processes in rapid prototyping, CNC offers excellent repeatability, high accuracy and a wild range of material selections and surface finishes. It is not only good for one-off jobs but also great for medium to high volume production.
Automotive industry accounts 40% of rapid prototyping area, new product development cycle continues to be shortened, the cost continues to decline, there are data that ten years ago requires four years of the development cycle of automotive products; today only takes two years to complete. In addition to the state-of-the-art developments in advanced product development, virtual manufacturing and simultaneous engineering used by car manufacturers, it is amazing to benefit from the efforts of technology. The challenge always encourages us seeking a new method to improve our quality, so we could always make the best rapid prototypes that come to the market.