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What are the steps of the membrane switch inspection?



What are the steps of the membrane switch inspection?

1. Material inspection: The panel, substrate, silver paste, carbon ink, spacer, adhesive, adhesive, reinforcing plate, and insulation printing should meet the requirements of the drawings.


2, shape comparison: shape, conductor lines, insulation treatment, liner combinations, etc. shall comply with the drawings or provide physical samples.


3, check the size: the tolerance of the drawings not to note tolerances to meet the standards, the rest in line with the drawings.


4, check the appearance: the panel can not have obvious defects, such as character lack of strokes; stains, light points; deinking, stains, scratches; transparent window overflow glue, residual glue and so on. No deviation phenomenon, such as the printing layout, upper and lower line key combinations, line and key sheet, panel and key combination, panel buttons at the bubbling and substrate. The size of punching burrs and extrusions shall not be greater than 0.2 mm and the position shall be towards the side without conductors.


5, check the color: the use of visual methods, with the sample or color card to see if there is a color difference, the color requirements are particularly strict contrast with a color difference meter.


6. Check the adhesion of ink: The ink is affixed with a transparent tape and the hand pressure is ensured that the bubbles do not peel off quickly after 10 seconds and there is no ink drop phenomenon. After the insulating ink is dry, after the ink surfaces are pressed against each other and then pressed for 24 hours, it is necessary to ensure that the insulating surfaces do not adhere to each other. Pressure-sensitive adhesive tape was applied to the hand pressure for 1 minute without bubbles, and peeling quickly without ink peeling off.


7. Peel strength test: The peel strength of the adhesive should not be lower than 8N/25mm.


8, bubble detection: equal height, intensity of balance. Flat type: 57 to 284g force, touch feeling: 170 to 397g force.


9, bending strength test: after drying the silver paste, carbon ink line, should first determine the loop resistance, and then to its line to do 180 degrees of folding, and pressurize the finger 2kg/2 seconds, and then make it to restore the plane , so back and forth five times, and then measure its resistance. The resistance increased by folding back 5 times does not exceed 300% of the original resistance.


10, hardness testing: H-level drawing pen, 45 degrees to the line 1kg thrust, the line may not have conductive ink peeling or produce light.


11, life test: no shrapnel contact each button to turn on the number should be in 1 million times. With shrapnel and tactile conductions, it should be 500,000 times.


12. Loop resistance detection: The resistance value should not be greater than 100Ω, for the total loop length greater than 150cm and the special requirements loop resistance is additionally specified on the drawings. No disconnection or short circuit is allowed.


13, insulation resistance detection: In the normal temperature and humidity environment, the insulation resistance of the conductor line is greater than 500MΩ (500VDC1 minutes). After the high temperature and humidity test, salt spray test should not be less than 20MΩ.


14, high temperature test: Membrane switch withstand 55 ± 2 °C, which lasted 72 hours after the high temperature effect, check the appearance of the quality should meet the requirements of the drawings. After recovering for 2 hours under normal atmospheric conditions, the insulation resistance value shall be measured in accordance with the regulations.


15, low temperature test: Membrane switch is subjected to -10 ± 3 °C, which lasted 16 hours after the low temperature effect, recovery under normal atmospheric conditions for 2 hours, wipe the surface of water droplets, the resistance value should meet the requirements.


16. Salt spray test: The membrane switch is subjected to 5% salt solution of sodium chloride, the test space temperature is 35±2°C, (connector sealing) After 72 hours of salt spray test, it is restored under normal atmospheric conditions for 2 hours. Insulation resistance should comply with regulations.


17. Constant Moist Heat Test: Membrane switch subjected to 40±2°C, relative humidity 93 (+2% –3%), after 96 hours of constant damp heat test, recovery under normal atmospheric conditions for 2 hours, measurement of insulation resistance, circuit Resistance, button strength should meet the requirements.

Hangzhou Kaike Electronics Co., Ltd.

Address: No. 2. Dadi Road, Haining Agricultural External Development Zone 314408,

Zhejiang, China

Contact Person: May Wong

Telephone: 86-571-86830690     Fax: 86-571-86687367

Cell Phone: 86-15158112598

Email: May@hzkaike.cn

Website: www.hzkkelec.com          

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