geekhack
geekhack Community => Keyboards => Topic started by: Kamen Rider Blade on Sun, 16 February 2014, 02:30:30
-
I'm not talking about Topre switches, but just classic Rubber Domes.
Most traditional Rubber Domes are limited to ~ 1-5 million clicks of durability if they're even listed at all
Yet higher end Rubber Domes can have durability up to 15 million clicks which is getting into the realm of Mechanical keyboards.
From my research, switching the Rubber Dome material to Silicone helps with the durability factor.
What other changes from traditional Rubber Dome KB construction is necessary to bring the KB up to the 15 million clicks level or better?
Maybe using a PCB instead of a flexible plastic circuit sheet?
Any ideas from the knowledge folks here?
-
Most traditional Rubber Domes are limited to ~ 1-5 million clicks of durability if they're even listed at all
Rubber domes don't click. The word "click" refers to a click sound. A "clicky" keyboard switch emits a click sound, and so far all clicky keyboard switches have been mechanical. A click sound could also be emitted by electronics through a solenoid or a speaker, but then it wouldn't be a property of the keyboard switch.
The term you are looking for is "key press". You could also use the word "actuation" which implies that the key press has succeeded in being recognized electrically.
What other changes from traditional Rubber Dome KB construction is necessary to bring the KB up to the 15 million [key presses] level or better?
Maybe using a PCB instead of a flexible plastic circuit sheet?
Model M buckling springs have membranes as the actuation mechanism and often work fine for a very long time. I believe it is mostly when keyboards have been subjected to spills (coffee, tea, soda...) that membranes erode and break or short.
Topre and Model F buckling springs use capacitative sensing, which is contact-less and should last mechanically for longer but they are still sensitive to erosion and shorts.
Many types of keyboard switches will also worsen in feel a lot before they break. Topre rubber domes get stiffer. Regular rubber domes not only get stiffer but also a mushier landing.
Key Tronic used to have rubber dome/membrane keyboards called "Lifetime Series" because they had been engineered to last - but there was really nothing spectacular about them.
-
I have typed on a few rubber domes which had PCB mounted domes and steel backplates along with sliders. Can't remember the exact brand. The keys themselves still felt like crappy old rubber domes, but the board in general did have a much more solid and satisfying feel than a cheap all plastic & membrane rubber dome board.
-
I think high end could refer to a number of things. High end as in great tactility and quality feel as well as durability and longevity. You seem to be considering the latter, where for instance very sealed constructions won't let contaminants in between the contact points as easily. Polymers which age better and are more resilient will of course also increase the longevity. The dome can be designed to not have some weak at the points where it bends the most etc. The contact points could develop an oxide layer as well so a nice and thick plating which doesn't wear off could alleviate that somewhat.
There are some examples at least.
-
So what causes Rubber Domes to require more force / pressure over time until they finally stop working?
-
isn't that a natural property of rubber? that's what i was always tols. rubber just gets hard when constantly put under pressure
-
<iframe width="560" height="315" src="//www.youtube.com/embed/jKC-RwNfXPI" frameborder="0" allowfullscreen></iframe>