Metal middle frame machining process

1. A method of machining a metal middle frame, the method comprising:

obtaining a sheet material, and cutting the sheet material into a linear profile;

performing a finish machining to the linear profile;

bending the linear profile after finish machining, obtaining a metal border frame with an R angle;

performing standard detections to the R angle, crack, and flatness of the metal border frame in such a manner that the R angle is consistent to the standard, a surface of the metal border frame has no crack, and a flatness of the metal border frame is less than 0.12;

welding the metal border frame; and

placing the metal border frame after the welding in a die-casting mold, providing a die-casting metal liquid, thereby obtaining a die-cast middle plate connected to the metal border frame, so as to form the metal middle frame.

2. The method of machining the metal middle frame according to claim 1 , further comprising:

performing an auxiliary machining to the metal middle plate to obtain an antenna groove; and

surface treating the metal middle plate.

3. The method of machining the metal middle frame according to claim 1 , wherein the finish machining comprises: machining a dovetail groove on the linear profile.

4. The method of machining the metal middle frame according to claim 3 , wherein the dovetail groove has a depth of 0.08 nm, and an opening of the dovetail groove has a minimum width of 2 mm and a maximum width of 2.3 mm.

5. The method of machining the metal middle frame according to claim 3 , wherein the welding is to joint at least two metal border frames together by welding end seams of the metal border frames.

6. The method of machining the metal middle frame according to claim 5 , wherein a seam width at the end seam of the metal border frame is 0.05 mm to 0.15 mm.

7. The method of machining the metal middle frame according to claim 1 , wherein the finish machining comprises: machining a patch groove on the linear profile.

8. The method of machining the metal middle frame according to claim 7 , wherein the patch groove has a depth of 0.02 mm.

9. The method of machining the metal middle frame according to claim 7 , wherein the welding comprises:

providing an L-shaped metal patch and performing the finish machining;

attaching the required metal patches in the patch groove in sequence and performing welding; and

joint at least two metal border frames together by welding end seams of the metal border frames.

10. The method of machining the metal middle frame according to claim 9 , wherein the metal patch is finish machined to obtain a plurality of irregular-shaped bayonet, a fully enclosed welding is performed to a periphery of an attaching surface of the metal patch and the metal border frame.

11. The method of machining the metal middle frame according to claim 10 , wherein the irregular-shaped bayonet is a C-shaped bayonet or a trapezoidal bayonet.

12. The method of machining the metal middle frame according to claim 10 , wherein a length ratio between the metal patch welded on a long side surface of the metal border frame and the metal patch welded on a short side surface of the metal border frame is equal to a length ratio between the long side surface and the short side surface.

13. The method of machining the metal middle frame according to claim 1 , wherein the die-casting metal liquid has a temperature of 610° C. to 630° C.

14. The method of machining the metal middle frame according to claim 13 , wherein a filling rate of the metal liquid is 28 m/s to 32 m/s, and a filling time is 0.013 s to 0.015 s.

15. A method of machining a metal middle frame, the method comprising:

obtaining a sheet material, and cutting the sheet material into a linear profile;

machining a dovetail groove on the linear profile;

bending the linear profile to obtain a metal border frame with an R angle;

jointing at least two metal border frames together by welding the metal border frames; and

placing the metal border frame after the welding in a die-casting mold, providing a die-casting metal liquid to fill the dovetail groove, thereby obtaining a die-cast middle plate connected to the metal border frame, so as to form the metal middle frame.

16. A method of machining a metal middle frame, the method comprising:

obtaining a sheet material, and cutting the sheet material into a linear profile;

machining a patch groove on the linear profile;

bending the linear profile to obtain a metal border frame with an R angle;

providing an L-shaped metal patch and performing a finish machining to obtain a matched L-shaped metal patch;

attaching the matched L-shaped metal patch in the patch groove in sequence and performing welding;

jointing at least two metal border frames together by welding the metal border frames; and

placing the metal border frame after the welding in a die-casting mold, providing a die-casting metal liquid to combine the metal patches, thereby obtaining a die-cast middle plate connected to the metal border frame, so as to form the metal middle frame.