Common problems and corresponding solutions of silicone injection molding products

3 tips to extend the life of silicone buttons

Q1: “The silicone buttons stopped working after a long time? Cleaning doesn’t help. Is it a design flaw?”

A : 90% of failures are caused by silicone aging !

Poor contact of the Conductive strip: The silicone button is connected to the PCB board through the conductive strip. Long-term extrusion or moisture will cause oxidation.

Solution: Gently wipe the conductive strip contact with an eraser, or replace it with an upgraded model with a compression ratio of 10%-15%.

Silicone hardening : Cheap silicone (hardness <40 Shore) is prone to aging and hardening. Choose 60-70 Shore medical grade silicone, which has a lifespan three times longer and can withstand high temperature sterilization at 200°C.

Compared with rubber keyboards : Rubber Keyboards are easily deformed due to UV radiation and thermal expansion (soften at 120°C), while silicone has stable performance at -40°C ~ 200°C.

Q2: “Why do silicone buttons feel softer and softer? What if the tactile feedback disappears?”

A : The killer of touch is the wall thickness design and injection molding process !

Gold wall thickness : The optimal thickness of the elastic wall of silicone buttons is 0.3-0.6mm. Too thick (>0.6mm) will make pressing difficult, and too thin (<0.3mm) will easily tear. Tesla Cybertruck uses a 0.4mm wall thickness + 45° bevel design, which takes into account both hand feel and durability.

Injection parameters :

Temperature: The barrel temperature must be precisely controlled (±5°C) to avoid burning of the silicone or lack of fluidity.

Pressure: Too low injection pressure will lead to insufficient filling. It is recommended to optimize the parameters in combination with Moldflow fluid analysis.

The pain of rubber keyboards : Rubber easily becomes sticky due to oil penetration, and feels "draggy" to the touch, while the silicone surface is highly oleophobic and remains dry after long-term use.

Q3: “The edge of the silicone button is cracked? The problem still exists after replacing it. Is it a material problem?”

A : The culprits of cracking are residual stress and mold design !

Injection molding process improvements :

Reduce injection pressure (<80MPa), shorten holding time, and reduce internal stress.

Use multi-point gates (such as side gates and fan gates) to avoid stress concentration near the direct gate.

Mold optimization :

Increase the demoulding slope (R ≥ 0.5mm) to reduce demoulding resistance.

The mold temperature uniformity error must be <±2°C to prevent local overheating and silicone degradation.

Rubber keyboard comparison : Rubber has a high coefficient of thermal expansion (3 times greater than silicone), so it is more likely to crack under temperature differences, doubling the repair cost.

Q4: “How do medical silicone buttons pass FDA certification? What is the difference between them and industrial grade ones?”

A : Medical grade silicone’s 99.99% antibacterial rate and biocompatibility are the key!

Material certification : Need to pass ISO 10993 biocompatibility test to avoid human rejection. Mayo Clinic case shows that medical-grade silicone buttons reduce ICU infection rates by 30%.

Process upgrade :

Laser engraving characters: avoid ink penetration and contamination while achieving backlight transmission (transmittance>90%).

Aseptic injection molding environment: The cleanliness level of the workshop must reach ISO 7 level to prevent microbial residue.

Limitations of rubber keyboards : Rubber has high porosity, is easy to breed bacteria, is not resistant to ethanol disinfection, and turns yellow and deforms after long-term use.

Q5: “Esports players complain: Silicone switches don’t respond as fast as mechanical switches?”

A : The secret of 0.01 second response lies in the conductive layer design !

Metal dome vs carbon particle conductivity :

Metal Dome (0Ω resistance): Suitable for high-speed triggered gaming devices.

Carbon particle conductivity (100Ω resistance): low cost, but life span is only 500,000 times, suitable for home remote controls.

Injection molding black technology :

Adding Boron Nitride: Increases the thermal conductivity of silicone to 12W/m·K, preventing heat accumulation during high-speed operation.

3D printed mold: achieve 0.05mm accuracy to ensure the consistency of key travel.

Disadvantages of rubber keyboards : The rubber rebound speed is slow (0.04s), and the APM (operations per minute) of professional players decreases by 15%.

Pro Tips: 3 steps to extend the life of silicone buttons

Antifreeze lubrication : Apply silicone grease in -40℃ environment to prevent silicone from hardening.

Intelligent monitoring : embedded RFID chip, real-time monitoring of button press times, early warning and replacement .

For more information, please contact: https://www.cmaisz.com/