Shield design rules and precautions

1. The overall dimensions of the shield are generally ≤50mm, and the flatness is controlled within 0.1. The side gaps around the shielding frame and shielding cover in the X and Y directions are 0.05mm; the top gap in the Z direction is 0.
2. The nozzle suction cup of the automatic production machine of the shielding frame is generally a circle with a diameter of ≥5mm or a 4╳6mm rectangle. The suction cup connecting strip and the frame edge are designed with a gap to facilitate maintenance and trimming. The gap width is generally 0.6~0.8mm.
3. The gap between the bottom of the bent edge of the shielding cover and the PCB should be at least 0.3mm. This is mainly to prevent solder paste from climbing up the wall and pressing against the shielding cover, affecting the assembly; for the stretch shield frame, the bottom of the bent edge of the shielding cover and the flanged welding feet of the shielding frame. The Z-direction gap is greater than 0.1mm
4. The diameter of the through hole on the shielding frame and the shielding cover is generally Φ0.6mm; the root diameter of the bumps on the shielding cover is Φ0.80mm, and the protrusion height is generally 0.15mm.
5. The shielding cover cannot be made into a stretched piece, and can only be made into a bending process; the shielding frame can be bent or stretched, but the material thickness of the stretched shielding frame must be 0.20mm, and the height must be ≥1.25mm. The minimum internal R angle at the corner must be at least 1.0mm, the minimum external R angle must be at least 0.65mm, and the welding flange must be ≥0.20mm;
6. The shielding frame/cover must be designed with buckle points, at least one buckle point needs to be designed on each side, and one buckle point is added for every 5mm increase, that is, at least 1 buckle point for 5mm, 2 buckle points for 10mm, and so on.
7. The distance between the edge of the fastening hole of the shielding frame buckle point and the top surface of the shielding frame is ≥0.4mm, and the distance from the center of the fastening hole to the top surface is ≥0.8mm. Generally, it is not allowed to be less than 0.65mm.
8. Both the shielding frame and the shielding cover must be designed with foolproof signs, such as engraved direction arrows. Generally, the direction of the arrow is engraved according to the direction of the shielding component in the Layout given by the Internet.
9. When the outer dimension of the shield is ≥30mm, the length and width tolerance is +0.08/-0.08mm, and the height tolerance is ±0.05mm; when the outer dimension is <30mm, the length and width tolerance is +0.05/-0.05mm, and the height tolerance is ±0.05 mm.
10. The Z-direction clearance between the PCB shielding cover and the structural component shell is ≥0.5mm, the X/Y-direction clearance is ≥1.0mm, the clearance around the components that are easy to short-circuit in the shielding cover is ≥0.5mm, and the clearance between ordinary components and the surroundings is ≥0.3mm. , the Z-direction gap is at least 0.3mm (less than 0.2mm, add insulating tape or spray insulating paint) to prevent short circuit; especially the gap between the components outside the shield and the shell generally requires a Z-direction gap ≥ 1.0mm, X /Y direction gap ≥1.5mm.