We all know that the snap dome (also named as metal dome) is very important for the conduction of electronic product as they provide tactile feedback and act as a switch. However, poor contact of the metal dome can result in malfunctioning or unresponsive buttons, which can greatly affect the user experience or even affect the function of the whole product. Then if a product has a conduction problem, is it certainly caused by snap domes? Certainly not. Let’s briefly introduce several situations of poor contact of snap domes.
1. Contamination
Contamination is one of the primary factors that can lead to poor contact of the snap dome, when there is a contamination on the contact side between metal domes and PCB boards, it will affect the normal conduction of metal domes. Sometimes, dust, dirt, stain, moisture, and other contaminants can accumulate on the surface of the metal dome over time, causing an insulating layer to form. This insulating layer can interfere with the electrical conductivity of the metal dome, leading to poor or no contact when the dome is pressed. So cleaning the surface of snap dome when you are going to assemble it on a PCB or flex circuit is a necessary and very important step.
2. Deformation
Metal domes can deform over time due to repeated use or exposure to high temperatures. Deformation can cause the metal dome to lose its original shape and fail to make proper contact when pressed, resulting in poor performance or non-functioning buttons. 3. Incorrect Design or Installation
Poor design or installation of the metal dome can also lead to poor contact. For a simple example, if the external diameter of PCB pad is 5mm, while the dome size is 6mm, when pressing down the metal dome, it will exceed the pad and cannot connect so that it won’t work. Normally Best Technology suggests that the external diameter of PCB pad should exceed at least 1mm than that of metal dome to ensure the good contact and high reliable of the snap dome.
In the same way, if the deviation of metal dome assembly is too big, it may also affect the conduction. Because normally we press the center of metal dome to make product be connected, if the assembly is deviated too much and not align well, it may actually work on the side of metal dome but not on the center when we press the center of product, indicating that the dome cannot down on the PCB pad to make conduction.
4. Corrosion
Corrosion is another factor that can lead to poor contact of the metal dome. Corrosion can occur due to exposure to moisture, chemicals, or other environmental factors, leading to the formation of a non-conductive layer on the surface of the metal dome. For this problem, we can use corrosion-resistant materials for metal domes, such as stainless steel or gold-plated metal domes, can help to minimize the risk of corrosion. Proper storage and handling of metal domes to prevent exposure to moisture or chemicals are also important. 5. Wear and Tear
Over time, metal domes can experience wear and tear due to repeated use, resulting in poor contact. The metal dome’s spring force may weaken, or the contact area may become worn out, leading to inconsistent or no contact.
6. Gap
If your product has a silicon keypad and the gap between silicon keypad and PCB boards is too large, then it will result in poor conduction problem. As we are pressing the silicon keypad to make metal dome down in order to connect with PCB board, if the gap is too large, we cannot make the dome down on PCB pad.
In a word, proper cleaning, maintenance, design, installation, and material selection can help to prevent poor contact and ensure the reliable performance of snap domes in electronic devices. Regular inspection and replacement of metal domes when necessary can also help to maintain good contact and enhance the overall user experience. Contact us to get your high reliable snap domes immediately.
