Unlike the other mounting methods, posts are only applicable to systems with cases that include a mount for the keyguard. The Via Pro system from PRC is an example:
These keyguards normally have a top edge with two extensions on both ends and the extensions have cylindrical posts extending out to the sides:
Begin by designing your keyguard as you normally would: case opening measurements, app layout and grid layout.
Take the case opening measurements from the inside edges of the manufacturer’s keyguard mount:
Take these measurements and enter them into the “Tablet Case” section:
Now enter the normal app layout and grid layout measurements and create a basic keyguard design:
You “could” print this keyguard and use it with your AAC system but it wouldn’t take advantage of the special mounting system provided by the manufacturer. So instead, choose “Posts” from the “Mounting Method” pull down:
You may now see a very strange looking keyguard design. You’ll see posts but the posts may be connected to the rest of the keyguard with very thin legs – or nothing at all:
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| narrow connection | no connection |
If you look closely at the app, you will find that there is very little space between the edge of the screen and the commercial keyguard mount. To address this problem, add additional plastic to the left and right sides of the keyguard using these options in the Case Info section:
Unfortunately, there’s no free lunch. In order to add this extra plastic, you’ll loose visual and manual access to the left and right edges of the message bar.
Next, expand the “Posts Info” section and enter the following information:
The first two measurements are described in the following picture:
If you already have a keyguard you’ve purchased for this system, you can take several measurements directly from that keyguard. If not, you’ll have to experiment a bit by printing a test keyguard and adjust as necessary.
If the top of the post matches the top surface of the keyguard and similarly for the bottom of the post, then the post diameter is the same as the thickness of the keyguard. Note that the keyguard designer will support you in creating a keyguard that has a thickness that is independent of the diameter of the posts.
The next measurement is described in the picture below:
The measurement is taken from the top edge of the case opening to the center of the place where the keyguard posts snap into place. Take your time with this measurement or the keyguard won’t fit properly at the bottom and may not sit close to the tablet surface.
You can create a “notch” in the face of both posts:
The notch can make it easier to snap the post into place and can help balance the keyguard when raised. If the manufacturer’s keyguard has this notch then include it in your design as well.
The keyguard surround may, additionally, have indents for a pair of mini tabs at the bottom of the keyguard to snap into. The indents and tabs help hold the keyguard against the tablet face:
The following pictures describe the measurements to take for these tabs. Again, if you already have one of the manufacturer’s keyguards then you should take these measurements from that keyguard:
Note: if you set the mini tab height at a value larger than zero, you’ll need to turn on supports in your slicer before printing your keyguard.