Air vent hole (air vent slot) is a small path that located around the metal domes or between domes, which is an important element for the normal operation of the dome array. It is available for almost of applications, so that when we press the metal dome, the air will go out through the small path. Therefore, in another word, air vent hole is related to the clicking feel and function of the dome array or tactile membrane switch.
The location of the vent slot is extreme vital for the function of the whole product. Normally, there are three ways to design the vent holes, each way has its advantages and depends on the specific requirements. Herein, we would like to introduce these ways to make you sense to them.
What is the importance of the air vent hole on dome array?
Typically, the vent hole serves as a pathway for air to release, maintaining balanced pressure and preventing potential issues such as sticking, inadequate response, or non-operational switches. The primary role of the air vent hole is to equalize pressure between the metal dome and the substrate. When a user presses a metal dome, the air underneath it needs to escape to ensure a stable and dependable tactile response. The presence of the air vent hole facilitates the immediate release of trapped air, allowing the dome to collapse and establish proper electrical contact. Without the vent hole, the dome may not perform optimally, leading to inconsistent or unresponsive keystrokes. Therefore, when pressing the snap dome, a vent slot is essential to prevent the compression of air underneath.
The ways to design air vent hole
There are three ways to make the vent holes on the dome array, which including:
1.Design air vent holes between metal domes and spacer
The first way is the most popular and easy to make, that is designed between the metal domes and spacers, just like below image. By this way, we can design the vent slot everywhere we want, and the path can longer or short. It depends on the distance between the two metal domes. But there is a tip that you must know – by this way, the air vent slot must between the spacer between the two metal domes, so that the air can be vented smoothly.
2.Make the small opening hole on the top layer of dome retainer
If your space between metal domes is limited, make a small opening on the dome retainer also is a good idea for air flowing. It can designed according to your preference.
3.Make hole on the PCB
In almost way, the dome array or metal domes are always assembled with PCB or flex circuits. So you can make a hole on the PCB like below image, by this way, the air can be flowed out through this small hole.
Each of these vent hole placements has its advantages and may be selected based on specific design considerations, such as the desired tactile response, overall switch performance, and manufacturing requirements. The choice of vent hole placement can impact factors like actuation force, key feel, and the prevention of issues like sticking or poor responsiveness in dome array applications.
