geekhack
geekhack Projects => Making Stuff Together! => Topic started by: Ari Gold on Mon, 19 September 2016, 06:24:35
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Hey,
I've noticed quite a bit of keyboards with plate mounted keys have their plate floating, not attached to the case directly. But still use the pcb to screw the construction to the case. Similar to the Poker or minivan. Wouldn't this still result in muchy typing due to pcb flex? Isn't it far better to mount the switches to the plate and have the plate connect to the casing directly? Similar to the GON keyboards?
Small drawing with elite paint skills:
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There are some keyboards that offer a reinforcing plate between the switch plate and PCB such as winkeyless.kr boards. The issue you're describing doesn't cause too much flex in tray mount cases due to the placement of the stand-offs under neither the PCB.
The reinforcing plate is used in winkeyless.kr boards because their style of case is a sandwich case where their is no support underneath the PCB; the PCB is suspended or floating. GON is a sandwich case as well, but IIRC they do not use a reinforcing plate but this may be because they are using an aluminum switch plate versus winkeyless.kr's acrylic switch plate (do not quote me on this, it is just my thoughts as I'm not that familiar with GONs work). The only support being given to the PCB in a sandwich case is by the switches and switch plate, so without the reinforcing plate between the acrylic switch plate and PCB the bend is much more apparent than in a tray mount case.
Needless to say there will always be some flex to a board if it's not on a flat surface, but I would guess that an aluminum tray style case would be your best bet if you are looking to avoid this issue. But from what I have felt it does not effect the typing experience all that much for me.
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In my experience, a floating plate still reduces flex over no plate at all and a fixed plate further reduces flex. Also, if you accidentally step on your keyboard, a fixed plate design will transfer the force to the case via the plate instead of the PCB.
I note that PCB mount designs tend to have stand-offs more evenly distributed. Classic Cherry keyboards have bars that extend along the length of the keyboard and more modern keyboards usually have a stand-off or two somewhere in the middle. Fixed plate designs, OTOH, are almost always fixed via the edges with zero support in the center area. Intuitively, I think edge-fixing with a stainless steel plate is more than adequate to prevent noticeable flex even on full-length boards.