How To Design The Gap Distance Between the Rubber Keypad and Housing Shell & Panel

How To Design The Gap Distance Between the Rubber Keypad and Housing Shell & Panel?

When we design a rubber keypad, not only need to consider its tactile and non-tactile characteristics, water and chemical resistance property, laser etched or silkscreen surface characters, conduction way, surface protective coating etc., A qualified finished rubber button needs to be combined with the shell assembly of the button to determine its overall gap structure.

Why is proper clearance critical for rubber button assembly?

When customers send us the 2D&3D design drawings of silicone buttons, we usually ask them to provide the assembly drawings of the rubber switches for analysis together, so as to avoid the rubber keypad encountering stuck of keys, actuation force & tactile feels issues etc., during the rubber button&plastic housing shell's assembly process.

A reasonable gap distance should be reserved between the rubber keypad and the housing shell & panel, so it can ensure the function and appearance requirements of the rubber button after assembly. If the gap distance between the silicone button and the housing case & panel is too small, will easily lead to numbness or even stuck keys. But the gap also should not be too large, excessive gaps will not only affect the appearance, but also easily cause external dirt to pollute the interior of the equipment,such as electronic components and circuit boards/PCB etc.

How much the gap distance between the rubber switches and the housing shell & panel should be designed?

We generally recommend that the gap distance should reserve 0.3mm on one side, and the minimum should not be less than 0.2mm. Because according to our long-term silicone button design experience, the gap of 0.2~0.3mm is suitable for most application scenarios of silicone buttons.

However, the gap of 0.2~0.3mm is not a standard value. Strictly speaking, the gap between the silicone button and the shell and panel should be determined according to the shape, size, stroke/key travel and other data of the KEY.

Generally speaking, if rubber keypad with regular KEY shape, small stroke, small size, the small gap can meet the requirements of function and appearance. On the contrary, a larger gap/space needs to be reserved.

When the key travel/stroke of the rubber keypad is ≤1.0mm

Note: "/" in the following table indicates the unrecommended KEY sizes

When the key travel/stroke of the rubber button is 1.5mm

Note: "/" in the following table indicates the unrecommended KEY sizes

When the key travel/stroke of the rubber switch is 2.0mm

Note: "/" in the following table indicates the unrecommended KEY sizes

Xiamen Better Silicone Rubber Co.,ltd is specialized on Prototyping and Full-Scale Manufacturing of rubber keypad/button/switch, which produce quality rubber switches and keypads for a variety of industries including home healthcare, gas-detection equipment, and industrial controls.

If your company requires a custom-designed rubber button switch, whether as a standalone product or part of a larger concept, XIAMEN BETTER SILICONE has a solution for you.  

To learn more about our collaborative design process, rigorous quality standards, and competitive pricing, give us a call today.