FPC membrane switches are critical components in devices ranging from medical equipment to consumer electronics. People want good reliability and long service life. To ensure these membrane switches meet industry standards, rigorous testing is essential. Here are 7 key tests to check if FPC membrane switches are good.

 

1. Electrical continuity test

 

It verifies circuit functionality, and detects shorts or open circuits.

 

Use a multimeter or automated test equipment to check continuity across circuits. Apply probes to designated contact points, and measure resistance.

 

The resistance value should align with specifications (typically <1Ω for continuity). Any unexpected open circuits or short circuits between adjacent traces mean issues.

 

2. Tactile response and pressing force test

 

This test checks tactile feedback and required pressing force.

 

Use a force gauge to measure the pressure needed to activate FPC membrane switch. Repeat tests across multiple points to eliminate accidental factors.

 

The pressing force should remain within the defined range. 150–350 grams can be good. Inconsistent feedback or deviation of measured values suggest issues with metal dome placement and material fatigue.

 

3. Adhesion and peel strength test

 

This ensures that layers (graphic overlay, adhesive, FPC) are securely bonded.

 

90° or 180° peel test is good. Use a tensile tester. Apply force to separate layers, and measure the resistance.

 

Adhesion strength must meet manufacturer specifications, for example, ≥1.5 N/mm. Delamination or weak bonding indicates poor adhesion or improper lamination.

 

4. Work in harsh conditions

 

This tests performance under extreme conditions.

 

Expose FPC membrane switches to wide range of temperature cycles (-40°C to +85°C), high humidity (85-95% RH), or chemical exposure (cleaning agents), and do the test.

 

Membrane switches must maintain electrical continuity and physical integrity. Improper raw materials can cause problems, so products can't pass the tests.

 

5. Mechanical endurance (life cycle) test

 

It determines operational lifespan under repeated use.

 

Use a robotic actuator to press the FPC membrane switch repeatedly at a defined force (for example, 500000 cycles). Monitor for electrical failure and physical wear.

 

Everything must be good without increased resistance or loss of tactile response beyond the rated lifecycle. Cracks or contact degradation means poor durability.

 

6. Visual and dimensional inspection

 

There must have some easy ways to find cosmetic or alignment flaws.

 

Magnification is available for looking for defects like misprinted graphics, air bubbles, or misaligned layers. You can use calipers to verify critical dimensions, such as spacer thickness and button size. No visible defects or dimensional tolerances should be beyond ±0.1mm.

 

7. Insulation resistance and dielectric withstanding voltage test

 

The test ensures safety, and prevents electrical leakage. Apply a high voltage (e.g., 500V AC) between conductive traces, and measure insulation resistance.

 

The insulation resistance should exceed 100MΩ, with no arcing or breakdown during voltage tests.

 

Conclusion

 

FPC membrane switches must pass tests about electrical, mechanical, and environmental evaluations. These 7 tests identify defects, and ensure good reliability. JRPanel attaches importance to quality management to provide you good products.