How To Design Waterproof Silicone Keypad丨Keypad Manufacturing Process

How To Design Waterproof Silicone Keypad?

Silicone Keypad made at Xiamen Better Silicone Rubber Co.,ltd are used in a variety of devices. These devices all have difference requirements of rubber keypad, such as silicone keypad’s tactile feel, wear/abrasion resistance, actuaction force, lifetime, compression set etc., though silicone material itself is waterproof, if you want the silicone keypad to be waterproof, it is necessary to consider the waterproof keypad design structure combine with plastic assembly housing shell.

As we know, if the circuit board of the equipment / electronic components in silicone keypad are invaded by water & oil or other liquids, they can be easily damaged. Once the circuit board is broken, the whole assembly keypad device will be basically overhauled or directly scrapped. Therefore, it is very important to have a waterproof design for the silicone rubber keypad.

Waterproof Silicone Keypad Design Tips 

The waterproof silicone keypad is mainly achieved by following three aspects -

1. Designing rubber keypad without positioning / locating hole. 

Common silicone buttons will reserved holes for fixing / locating, but such design is easy to allow water to flow into the circuit board from the button surface, so the rubber buttons that need waterproofing will avoid designing positioning holes.

2.Designing the waterproof silicone keypad edge structure.

Creating a silicone waterproof wall that is higher than the thickness of the bottom of the silicone button (which is around the silicone keypad). Then designing a fixed/positioned groove (usually as a semicircle shape) on the edge of the waterproof wall according to the cooperation of the chassis, circuit board and buttons.(PS: the position of the fixing/locating slot needs to be a certain distance from the position of the circuit board)

In this way, even if the water drops to rubber keypad accidentally, it is not easy to flow into the device.

3.Using resin/glue for edge sealing.

There will be a certain gap between the silicone button and the assembly housing case. Coating with resin/glue material can achieve higher sealing effect. However, it may lead to a relatively high defect rate during the operation, moreover, it will effect the rubber keypad's appearance if the resin/glue overflows, thus engineer suggest to design a waterproof keypad directly.

Xiamen Better Silicone Rubber Co.,ltd as a professional waterproof keypad / silicone rubber keypad manufacturer, our factory always encounter some difficult design of the splashproof/waterproof silicone rubber keypad for outdoor use.

There is one of our French customer, who is designing a customize UV-resistance rubber keypad for motorcycle remote controller and ask us how to improve waterproof design of it. 

Below is original rubber keypad design from customer -

The requirements of custom silicone keypad are as following -

In the course of our product development, we are willing to make a custom rubber keypad for our new remote controller.

The controller contains 2 push buttons and 2 LEDs. You will find attached a file with the rubber keypad we thought of, and the whole remote controller in which it will be fitted. Of course the dimensions and in particular the thickness can be modified according to your suggestions (we have no experience in rubber keypads). The 2 buttons will necessarily be painted black with white “+” and “– “ symbols. The product needs to be splashproof (outdoor use on motorcycles).

Do you think it is possible to use a rubber keypad and keep the product splash proof?

So we could know the Custom Silicone keypad requirements are as below -

1 - Translucent silicone base

2 - Spray black coating on the key top

3 - Silk screen printing white symbols

From the customer’s descriptions, there is no any problem with manufacturing this silicone keypad, the most critical issue is how to keep the rubber keypad products waterproof / splashproof when outdoor use on motorcycles.

From original silicone keypad design structure, engineer notice that not only there is no any supports at the bottom of the keypad, also there is bot waterproof groove around the button. If the pressure is applied on the button top, the entire silicone keypad push down and moves, then there will be gaps between silicone keypad and plastic housing case, eventually it lead to non-waterproof.

Waterproof Remote Control Keypad Original Design -

In order to achieve the splashproof/waterproof function, our engineer team suggested that this waterproof silicone keypad should be designed as an integral shell, which is become a sealed and compact structure and wrap the electronic assembly parts closely and will not effect its application.

After design, this custom waterproof keyboard is designed with thicker wall to be full-sealed and waterproof. Silicone keypad case replace the most proportion of plastic housing shell, to protect the internal electronic components and with good appearance & great hand feelings.

Waterproof Keypad Combine with Assembly Parts Design After Modified - 

In order to present a better aesthetic effect and meet the outdoor waterproof keypad applications , there are final custom remote control silicone keypad manufacturing process -

1. UV resistance translucent silicone base

2. Spraying white coating

3. Spraying black coating

4. Laser cutting/etching/engrave translucent triangular LED window

5. Laser cutting/etching/engrave white symbols&legends&characters

6. Spray PU (Polyurethane) protective coating

For providing customer's with aesthetic waterproof silicone keypad products, our factory also make an extra positioning tool to spray the black coating on the buttom edge of the rubber keypad.

But it requires turning the silicone button over then spraying it again, thus will need a more production process, which will cost more labor cost and time, thus the unit price will be more expensive.

Extra Positioning Tool For Customizing Waterproof Silicone Keypad -

Waterproof silicone keypad prototypes has been validated, and then we have finished the pre-series production of 100PCS rubber keypad, this project is very successful and will go into mass production in the near future.