Foam is a polymer with many small pores. The solid phase is a polymer matrix. The small pores are filled with other gases, with low foaming ratio and high density. As a mobile phone accessory, it plays a role in the mobile phone: damping and decompression where the electronic components are in contact with the shell. Prevent crushing electronic components（ (used as shock pad)

1 .common scope

① LCD foam

② Camera foam

③ Horn foam

④ Sealing foam of horn rear sound chamber

⑤ Motor foam

⑥ Connector compression foam

2 .Foam - selection of materials

3. foam - selection of special materials

As the foam is thick and soft, in order to prevent the exposure of foam caused by extrusion deformation after pasting, 0.2mm shall be reserved on one side of LCD foam with large area, more than 0.5mm shall be reserved in the gap in the frame, more than 0.1mm shall be reserved on one side of camera foam, horn foam and motor foam with small area, and more than 0.2mm shall be reserved in the middle.

4 .precautions for foam assembly

5 .technical requirements to be indicated in engineering drawings

Description of technical requirements (including but not limited to):

① Material, detailed specification and brand;

② The foam edge must be punched and cut neatly without burrs;

③ There must be key control dimensions in the drawing, and "*" shall be added in front;

④ The thickness dimension in the figure is the dimension before compression;

⑤ Whether the waste is retained must be clearly marked;

⑥ When the incoming goods are delivered, the actual matching inspection shall be carried out for the corresponding assembly parts;

⑦ If it is customer supplied, it shall be indicated that "this is customer supplied material".

6 .conductive cloth (conductive foam) - function and material selection

Function:

Connect the hardware trim with the main board to prevent static electricity from burning the main board. The conductive cloth has the same function as the conductive foam, but the conductive foam is directly connected between the hardware trim and the main machine. If the conductive foam cannot be used due to structural constraints, the conductive cloth shall be used.

7 .conductive cloth - fabrication requirements

The back glue made of conductive cloth is conductive back glue, the length is customized due to structural constraints, and 0.1mm is reserved on one side of the width matching position gap.

The length should not be too long (no more than 1mm), because the conductive foam will be squeezed to connect with other parts of the motherboard after assembly.