CNC Rough Cleaning
The aluminum block enters into the first CNC process. The dedicated drill of theFrank (or partner's advanced CNC machine tool) is then used to mill thealuminum block for the proper position to fill with plastic cement. Differentcutting tools are required due to different structure designs for both sides of the aluminum block. The entire CNC process requires 21 cutting tools and takes 28minutes, with the accuracy being 0.02 mm. This CNC process lays the basis for asolid MX4 cover.
After the rough cleaning, the aluminum block is tainted with a small amount of mold-release agent and protection oil. MEIZU then uses alkali liquid to clean and degrease the mold-release agent and protection oil, and uses liquid acid to neutralize the alkali liquor. Then the aluminum block is soaked in specially formulated T liquid to create nano-sized micro-pits on the block, with the diameter of the concave surface being from 20 to 30 nano. The entire soaking process requires 8 solutions and takes 4 hours. This achieves nano-level fusion between the plastic cement and aluminum alloy, significantly improving the rupture strength of the MX4 cover.
The MX4 cover is not only a decorative frame but also a keel of the MX4. The MX4adopts an integrated structure design and its strength far exceeds that of othermobile terminals whose frame edge and framework are welded. Plastic cementneeds to be injected to isolate it from the antenna. MEIZU uses the advancedSumitomo injection molding machine to inject the PPS plastic cement that hasundergone 280°C T processing, into the MX4 cover, which closely grips the PPSplastic cement and the aluminum alloy.
CNC Fine Cleaning
The MX4 cover almost has no horizontal or vertical face. Instead, it is full of cambered surfaces and different-size R angles.This raises the requirements for the CNC machine tool and cutting tools. After the injection molding, the aluminum block undergoes 8CNC workstations, with a total of 70 groups of cutting tools used. The entire CNC process takes 90 minutes.Considering that the bottom of a common milling cutter is a pointed blade and is not suitable to process cambered surfaces,MEIZU customizes 25 types of T-type cutters, R-angle round cutters, and ball cutters for the MX4.These efforts are made to achieve a perfectly cambered surface and the comfortable touching of surfaces.
Manual Grinding and Polishing
Only the manual grinding can completely remove milling cut marks generated during thefine cleaning. The advanced grinding provider is then used. Each worker grinding the MX4cover has more than 5 years of manual grinding experience. The machinists use thegrinding wheel to grind away cut marks and a hemp fiber polishing wheel to removemarks from the grinding wheel. Finally, a cloth wheel is used to polish the cover until themirror-like effect is achieved. This processing perfectly addresses problems in the width,narrowness, and an overall evenness of fine roughness on the cambered surfaces.
16 sand-blasting guns at 360 degrees
MEIZU has sought for 9 months in the lab, the appropriate sand proportion among 8 types of sands. After trying more than 40 schemes,the most suitable scheme to match the 6061 T6 aluminum alloy cover was found. MEIZU applies the advanced sand blaster.
To ensure productivity and standardization, virtually all the same-type of sand blasters are in the Pearl River Delta region operations.
MEIZU uses 16 sand-blasting guns to blast the MX4 cover at 360 degrees without a dead angle, ensuring the comfortable touching on the cambered surfaces.
Color scheme replacement (deep gray replacement 8 times and gold replacement 10times) aims to make the MX4 more unique in your hand. For the MX4 to meet theadvanced anodizing technology, MEIZU applies 13 types of anodizing solutions whensoaking the MX4 cover. This process takes 2 hours. Mixing and replacement of allsolutions are all completed through the computerized operations system, withoutmanual intervention. The automatic production line ensures the color uniformity foreach MX4.
Fine Roughness Chamfering
The industry generally uses the 30,000/50,000-RPM engraving and milling machine to cut thechamfer. The iPhone uses the 80,000-RPM engraving and milling machine, which makes thechamfer shinier. MEIZU uses a 100,000-RPM engraving and milling machine to cut the chamferinto a mirror-like chamfer with the same width and narrowness, and without CNC cut marks.Then, MEIZU performs the second oxidization (electrophoresis for a white color) on the MX4 toform the protection layer. This makes the chamfer sparkle like a diamond, ensuring that the MX4cover outshines all other mobile terminals.
World's Advanced Gluing Technique
To build unprecedentedly solid screens and prevent screens from breaking, Meizu uses a specific glue to bond the screento the al-mg alloy body. The glue layer is 0.32 mm thick and not only affixes the screen, but also provides outstanding cushioning. Thanks to the innovative gluing technology, the screen is floated on the body. When the phone is dropped or impacted, the impact force is doubly cushioned by both the R-angle body and the glue, to minimize the possibility of a cracked screen.