When it comes to finding the right dome switch, designers must work around standard domes’ limitations or find a custom solution. So how do you know if metal dome switches are suitable for your application? Below are five of the most frequently asked questions we get from engineers investigating dome switches as viable solutions for their products.
1. How are metal domes packaged?
There are several different packaging methods to choose from, depending on your application. Metal domes can be packaged in bulk (jars), in cartridges for use with the Dart™ Placement Pen or the SureShot™ automated dome placement machine, in pocketed reels for use with pick and place equipment, or on polyester-adhesive sheets (Standard Peel-N-Place arrays or Custom Peel-N-Place arrays).
2. Can metal domes be soldered to a circuit board?
Snaptron does not recommend soldering metal domes to the circuit board. The feet of domes move outward when pressed. Soldering the domes to the circuit board restricts the feet from their natural movement. This restriction can negatively affect the tactile response of the domes, and in some cases, cause irreparable damage to the domes, break the solder joint or damage the circuit board.
3. How do I secure the metal domes to my PCB, membrane, or flex circuit?
Metal domes can be secured using pressure-sensitive adhesive tape. Several standard material options are available, as well as custom materials. See our Peel-N-Place Arrays for more information on placing the domes with tape. Domes can also be secured mechanically using features in the assembly or a pocket to orient them. A minor offset should be allowed so the dome can flex outward when actuated. Failure to do so may result in little to no tactile response.
4. Can metal domes be assembled with standard pick and place equipment?
Yes, Snaptron offers pocketed reel packaging for use with automated placement equipment. Please contact us for more information regarding automated metal dome placement equipment.
5. Is there a recommended actuator for depressing the domes?
While there are several different sizes and shapes of actuators, we recommend you test the metal domes’ actuation force with a flat bottom plunger 20-25% of the dome size. Anything larger has the potential to crush the dome and reduce its designed force and travel. Anything smaller can create a dimple in the dome and limit its designed travel. Different types of actuators can affect the tactile feel of our switch. For example, silicone actuators will provide a crisp tactile feel with dull acoustics. See our quality test procedures for more information on testing domes.
Are you interested in learning more about metal dome switches? Contact us today to learn if dome switches are right for your application.