The all-metal casings of 3C products are basically processed by Computer numerical control machine tools (CNC). CNC has become an essential equipment for 3C casing manufacturers due to its advantages of high efficiency, high precision and stable processing quality.
1. Working principle of CNC machine tools
First use drawing software such as UG to build a 3D model, then use programming software to write the process based on the 3D model, and finally import the data into the machine tool, install the workpiece, and start.
The all-metal one-piece CNC machining process was first pioneered by Apple - the aluminum plate is die-cast from solid columnar aluminum and is precision-machined to form the prototype of the integrated body. As the body gradually takes shape, the shape of the keyboard on the body and various minute structures are milled out.
This process includes a total of nine CNC milling processes, after which a precise one-piece shell is obtained.
From programming to obtaining finished products, shell manufacturers need to go through multiple processes such as rough machining, semi-rough machining, semi-finishing, and finishing. In many cases, the whole process requires more than 10 work stations to obtain finished products. If you want to improve the yield rate, each process All need to be strictly controlled.
2. Pre-processing work of CNC
Before CNC machining begins, modeling and programming are first required.
The difficulty of 3D modeling is determined by the product structure. Modeling products with complex structures is more difficult and requires more and more complex programming processes. Programming includes processing process settings, tool selection, speed setting, the distance of each feed of the tool, etc.
In addition, different products have different clamping methods. The fixture must be designed before processing. Some products with complex structures require special fixtures.
Programming includes the processing technology of the entire product. Although subsequent CNC automation is completed, early programming must be performed by experienced personnel to avoid repeated trials and errors that increase costs.
①DDG
Use a high-speed drilling and tapping center to accurately mill the aluminum plate into a regular three-dimensional volume of a certain size, preparing for the next CNC processing
② Rough milling
After positioning, the inner cavity structure, the positioning column combined with the fixture are roughly milled, and most of the external redundant material is milled away.
③Milling the antenna slot
The signal problem with the all-metal casing is very difficult. Antenna slots need to be milled out to leave a transmission path for signals, and necessary connection points must be maintained to ensure the strength and integrity of the fuselage.
④ CNC finishing
Precision milling of inner cavity, outer structure, outer surface, sides, etc.
⑤ Polishing: Use high-speed precision CNC machine tools for polishing to eliminate knife marks and prepare for subsequent sandblasting.
⑥Sandblasting
Treat metal surfaces to a matte effect.
⑦Anodizing treatment
Primary anode: Color the mobile phone, anodizing turns the aluminum into gold and improves the stability of the surface material;
Secondary anode: A strong and dense oxide film is formed on the surface of the fuselage, further enhancing the wear resistance.
Plastic shell molding uses injection molding technology, which can be mass-produced by just opening the mold, with a high yield rate. The CNC machining yield of an all-metal fuselage is determined by the structural complexity and precision requirements of the casing, making it difficult to achieve the high yield of plastic casings.
