Mobile phone metal body 12 large process
Metal back cover need to go through 12 major processes: DDG → CNC open rough → T treatment → PMH injection → CNC finishing → polishing → sandblasting (drawing, spraying) → an anode → C angle high light → secondary anode → anode polished → assembly
DDG (double end high speed grinding)
DDG full name: CNC double sidesurface grinder, through the double-end high-speed grinding aluminum will be carefully ground into a three-dimensional volume to facilitate the subsequent CNC finishing. Double-end high-speed grinding is a progressive grinding method, the use of both ends of the wheel set when the installation of a small grinding angle θ, grinding allowance was followed by grinding, to achieve hierarchical step-by-step removal of grinding (schematic as follows ), Cost and yield are better than existing CNC machining solutions.
Double-end grinding principle (left) and grinding wheel wedge angle schematic diagram, from Yuhuan NC
DDG obtained after the regular three-dimensional volume of aluminum
CNC open rough
CNC open rough include:
1) rough milling the cavity, the cavity will be most of the milling, and milling the connection fixture positioning column;
2) Milling the antenna slot, prepare for the T process, the antenna slot must be homogeneous, and maintain the necessary connection points to ensure the strength of the metal shell and the overall sense.
Rough milling chamber (renderings)
After milling the antenna slot, it is necessary to use the "T treatment" to deal with the aluminum can be combined with the surface of engineering plastics. Need to put the metal body in a special liquid T liquid and other chemicals, the aluminum surface to form nano-level (1 nanometer = 10 -9 cubic meters) holes for the next step to prepare PMH injection.
T effect after treatment
PMH injection molding
"Injection" link because of the T before the metal handle, which can make PMH injection molding process can be achieved. PMH technology is BYD's mobile phone metal housing antenna signal solution. Similar to NMT injection, the principle of PMH injection is that the surface of the metal after treatment with PMH technology forms numerous nanoscale microporous structures and then penetrates the plastic into the metal surface through injection molding and seamlessly engages with the metal , As the roots deep into the soil.
PMH injection molding principle, from the BYD official website
CNC finishing mainly include: fine milling arc, fine milling side, this process takes a long time, 3D arc back shell with a prototype.
Fine milling arc, fine milling side effect after the map
Polishing (Remove the knife marks)
Even through the fine milling, mobile phone metal shell surface can not avoid the emergence of a knife pattern, if the direct sandblasting will have uneven feeling. Through the use of 2.5D surface polishing equipment, you can eliminate the knife pattern, so that the surface touch with a delicate feeling.
3D arc after polishing effect map
Sandblasting (drawing, spraying)
In this step, if the effect is amber gold, then the use of metal carving texture process; if it is ceramic white effect, then the use of five layers of ceramic white coating process.
Metal wire drawing effect
Once an anode
Aluminum alloy is more stable, in order not to be sweat and other external factors interfere with, it must be its anode treatment. At the same time this is also the process of coloring for the phone, through the anodic oxidation of aluminum qualities into gold. For the aluminum alloy dyeing process is very difficult to control, poor control will appear color, spots, etc., which will reduce the yield.
C angle high light
C-angle highlight is the phone frame to show the letter "C" shape, and have a mirror highlight effect. This is done so that the phone has a more comfortable sense of hand and technology sense, in order to achieve this effect, you need to use the high precision of this ultra-high speed CNC machine.
C angle high light effect
Has been handled by the CNC shell also need a second anode treatment, the surface is oxidized to form a dense, hard oxide film, making it more wear and easy to stain.
Polishing (3D Shaped Finish)
According to U-ring CNC insiders said they have equipment to participate in the processing of Huawei P9 mobile phone metal shell, it is likely to be 3D profiled surface magneto-rheological polishing technology. The technology is the use of magnetorheological fluid in the magnetic field under the workpiece surface (including 3D surface and BP surface) for a polishing of the new polishing technology.
3D heteromorphic surface magneto-rheological polishing technology principle: magnetorheological fluid containing magnetic powder and abrasive, no magnetic field is liquid, in the magnetic field will become into a solid state. According to the shape of the workpiece changes, with adaptive capacity, and thus processing evenly, even 3D arc can also achieve mirror effect.
Metal wire drawing and ceramic white
Mobile phone metal shell assembly effect map