CNC Machining Used in Cell Phone Shell Machining
In this era where user experience is highly valued, more and more cell phone, notebook and wearable device manufacturers are starting to make efforts on the shell material. From the cell phone field alone, cell phone case materials are gradually transitioning from engineering plastics to metal.
Cell phone shell material evolution during the emergence of many kinds of combinations: plastic and metal, glass and metal, all plastic, all glass, etc., but ultimately did not overshadow the full metal material of the wind.
At present, 3C products are basically all metal shell by CNC machine tools (Computer numerical control machine tools, CNC) processing. CNC because of its high efficiency, high precision, stable machining quality and other advantages becomes the necessary equipment to 3C product shell manufacturer.
All-metal one-piece CNC processing process was first pioneered by Apple – after die-casting,the column of solid aluminum become sheet, by precision machining first cutting into the prototype of the one-piece body, as the body gradually formed, the body of the keyboard shape and a variety of fine structure are milled out. This process contains a total of nine CNC milling process, nine processes will be obtained after the precision of the unibody shell.
Shell manufacturers from programming to obtain finished products need to go through rough machining, semi-rough machining, semi-finishing, finishing and other multi-processes, many times the whole process requires more than 10 processes to obtain finished products, want to improve the yield rate, each process needs to be strictly controlled.
First, CNC machining pre-processing work: modeling and programming
The difficulty of 3D modeling is determined by the structure of the product, and it is more difficult to model products with complex structure, and the process of programming is also more complicated. The programming includes the process setting, tool selection, speed setting, distance of each tool feed and so on. In addition, different products have different clamping methods, so it is necessary to design a good fixture before processing, and some complex products need to make special fixtures.
Programming contains the entire product processing process, the subsequent although all CNC automation to complete, but the pre-programming must be practically experienced personnel to operate, to avoid multiple trial and error to improve costs.
Second, the main processing technology
Use high-speed drilling and tapping center to accurately mill the aluminum plate into a certain size of the regular three-dimensional volume, ready for the next process processing.
Rough milling: after positioning, rough milling out the inner cavity structure, the positioning column combined with the fixture, and milling away most of the redundant material outside.
Milling the antenna slot: the signal problem of the all-metal housing is tricky, so the antenna slot needs to be milled to leave the transmission path for the signal and keep the necessary connection points to ensure the strength and overall feeling of the body.
CNC finishing: Finishing milling of inner cavity, external structure, outer surface, side edges, etc.
Polishing: Use high-speed precision CNC machine tools to polish, eliminate knife patterns, and prepare for subsequent sandblasting.
Sandblasting:Treating the metal surface to abrasive effect.
Anodizing:
Primary anodizing: Coloring for cell phones, anodizing turns aluminum into gold. Also improve the stability of the surface material
Secondary anodizing: A solid and dense oxide film is formed on the surface of the body, which further enhances wear resistance.
Plastic shell molding using injection molding process, only need to open the mold can be mass production, the yield is very high. The CNC processing yield of the full metal body is determined by the structural complexity and precision requirements of the shell, it is difficult to achieve the same high yield of the plastic shell, in order to balance the high cost, most manufacturers will choose to purchase a large number of CNC equipment in the face of the price war to reduce the overall cost and achieve the productivity requirements.
