Inspection standard for finished products of valet board membrane switches


1. Wire break and short circuit: No conductor break or short circuit is allowed.

2. Foreign body: The circuit must not have any foreign body attached to it.

3. Conductor thickness: Generally, the thickness of the conductor is controlled at 7-12 μm, and it should be uniform and smooth.

4. The position deviation of the upper and lower lines: the center position of each switch contact of the upper and lower lines is offset from each other with a tolerance of Ф0.5mm.

5. Material: substrate, silver paste, carbon ink, septum, adhesive, adhesive, reinforcing plate, and insulation printing shall comply with the drawings.

6. Shape: shape, conductor line, insulation treatment, lining board combination, etc. should comply with the drawings or provide physical samples.

7. Defects and pinholes of conductors: judged according to the following illustrated standards, one per 50mm is allowed.

8. Carbon ink: The carbon ink covered on the silver paste line should ensure that the silver paste is completely covered. Its thickness is 8-10 μm, and there must be no obvious silver paste protruding.

9. Stamping burr and die squeezing dimensions: The stamping burr and squeezing dimensions should not be greater than 0.2mm, and the position should be toward the side where there is no conductor.

10. All membrane switch contact points: there must be no insulation ink attached, and the surface of the insulation ink should be smooth to avoid any bubbles or pinholes and other defects that affect the insulation effect.

11. Combined state: There should be no residual material scraps, foreign objects, stains, irregularities, grease attached to the surface and inside, fingerprints on the circuit, and burrs on the punched shape.

12. Scars: All lines and contacts must not have cuts that penetrate through the surface (ie, the cuts are cut from the substrate on the line), and minor scratches are based on the principle of not affecting their impedance, and carbon ink surfaces are prone to scratches. , Its scratches are based on the principle of not affecting the line conduction.

13. Adhesion strength: After the insulating ink is dried, the ink surfaces should be placed against each other and then pressed for 24 hours to ensure that the insulation does not stick to each other. After applying pressure sensitive tape for 1 minute without air bubbles, peel it off quickly, and no ink should fall off.

14. Jumper: All jumper parts are in accordance with the requirements of the line conductor, and all jumper products must pass 100% open, short circuit test and insulation resistance test. Make sure that there is no open, short circuit and insulation resistance should be greater than 500MΩ (500VDC for 1 minute)

Post time: Jul-08-2020

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