Production requirements for die-cutting of mobile phone accessories and shielding materials

Foam and foam die-cutting are high molecular polymers with numerous small pores. The solid phase is the polymer matrix, and the small pores are filled with other gases. They have a low foaming ratio and high density. As an auxiliary material in mobile phones, their role is to provide shock absorption, cushioning, and decompression where electronic components come into contact with the casing; they prevent the electronic components from being crushed (acting as shock pads).

1. Commonly used scope:

① LCD foam ② Camera foam ③ Speaker foam ④ Rear speaker cavity sealing foam ⑤ Motor foam ⑥ Connector pressing foam

2. Selection of foam material, selection of special foam material:

Due to the thickness and softness of the foam, to prevent foam exposure caused by deformation due to compression after pasting, a single side margin of 0.2mm is reserved for large-area LCD foam, with a gap inside the frame of more than 0.5mm. For magnetic material die-cutting and small-area camera foam, speaker foam, and motor foam, a single side margin of more than 0.1mm is reserved, with a central margin of more than 0.2mm.

3. Precautions for foam assembly

4. Technical requirements to be indicated in engineering drawings:

① Material, detailed specifications, and brand;

The edges of the foam must be neatly cut and free of burrs

④ The thickness dimensions in the figure are before compression

③ The key control dimensions must be indicated in the diagram, and a "*" should be prefixed;

⑤ Whether scrap materials are retained or not, clear identification must be made

⑥ When receiving goods, it is necessary to conduct actual matching inspection with the corresponding assembly parts;

⑦ If it is supplied by the customer, it should be indicated as "This is a customer-supplied material.".

5. Conductive cloth (conductive foam) - function and material selection:

Function: To establish a connection between the hardware decorative components and the mainboard, preventing static electricity from damaging the mainboard. The conductive cloth serves the same purpose as conductive foam, but conductive foam is directly connected between the hardware decorative components and the main unit. If structural constraints prevent the use of conductive foam, conductive cloth should be used instead.

6. Conductive fabric and conductive precision die-cutting - production requirements:

The adhesive on the conductive fabric is conductive adhesive, with a length customized due to structural constraints, and a width reserved with a single-sided clearance of 0.1mm to match the bit gap.

The length should not be too long (no more than 1mm), as an excessively long conductive foam may be squeezed and connected to other parts of the motherboard after assembly.

7. Conductive foam - Technical requirements to be specified in engineering drawings:

The edges of the die-cutting parts should be neat, with no visible fibers or debris residue, and there should be no wire drawing during assembly;

The adhesive application area on one side of the conductive foam cannot exceed the entire surface, to prevent the adhesive from insulating the entire surface from the metal parts;

③ The key control dimensions must be marked in the diagram, and prefixed with "*",

④ The size of the conductive foam is the size before being compressed;

⑤ If it is supplied by the customer, it should be indicated as "This is a customer-supplied material".

3. Precautions for foam assembly