I am looking into using push type solenoids to push microwave touch pad buttons. I understand that the force a solenoid exerts is dependent on stroke length. One site I was looking at listed two different stroke lengths for the same product depending on "preload". http://www.trossenrobotics.com/p/small-solenoid.aspx How am I to alter the stroke length of the solenoid to increase the force?
The force of the solenoid varies over the length of the stroke, reaching a maximum at the end of the stroke, when it is fully activated. The minimum force occurs when the solenoid is just starting to move from the deactivated state.
"Preload" refers to partially compressing the solenoid's return spring by mechanically preventing the solenoid from reaching its fully deactivated position. If you do this, the initial force when it starts to move will be higher, which is what the chart reflects.