The Zalman ZM-K700M Mechanical Gaming Keyboard Reviewby E. Fylladitakis on February 3, 2016 8:00 AM EST
In order to test the quality and consistency of a keyboard, we are using a texture analyser that is programmed to measure and display the actuation force of the standard keyboard keys. By measuring the actuation force of every key, the quality and consistency of the keyboard can be quantified. It can also reveal design issues, such as the larger keys being far softer to press than the main keys of the keyboard. The actuation force is measured in Centinewton (cN). Some companies use another figure, gram-force (gf). The conversion formula is 1 cN = 1.02 gf (i.e. they are about the same). A high quality keyboard should be as consistent as possible, with an average actuation force as near to the manufacturer's specs as possible and a disparity of less than ±10%. Greater differences are likely to be perceptible by users.
The machine we use for our testing is accurate enough to provide readings with a resolution of 0.1 cN. For wider keys (e.g. Enter, Space Bar, etc.), the measurement is taking place at the center of the key, right above the switch. Note that large keys generally have a lower actuation force even if the actuation point is at the dead center of the key. This is natural, as the size and weight of the keycap reduces the required actuation force. For this reason, we do display the force required to actuate every key but we only use the results of the typical sized keys for our consistency calculations. Still, very low figures on medium sized keys, such as the Shift and Enter keys reveal design issues and can easily be perceptible by the user.
The quality testing of the Zalman ZM-K700M gave us the expected results for a keyboard based on Cherry's MX switches. The actuation force is very consistent, with a disparity of just ±3.77%, which is imperceptible by touch. Furthermore, the actuation force of the larger keys, and especially that of the Space Bar key, is not much lower than that of the main keys, despite their size. Cherry's cross stabilizers balance the actuation force of the larger keys, bringing it closer to that of the main keys, enhancing the overall feeling of the keyboard.