{"id":6870,"date":"2022-04-18T08:42:31","date_gmt":"2022-04-18T14:42:31","guid":{"rendered":"https:\/\/volksswitch.org\/?page_id=6870"},"modified":"2026-03-21T15:49:45","modified_gmt":"2026-03-21T21:49:45","slug":"keyguard-frame","status":"publish","type":"page","link":"https:\/\/volksswitch.org\/index.php\/volks-devices\/customizable-3d-printable-keyguard-for-grid-based-free-form-and-hybrid-aac-apps-on-tablets\/keyguard-frame\/","title":{"rendered":"Keyguard Frame"},"content":{"rendered":"\n

Keyguard frames are used in two different ways – as a screen protector replacement or as a rigid frame for easily and quickly swapping keyguards or flipping up the keyguard.<\/p>\n

Keyguard frames work in conjunction with a keyguard to fill the space of the case opening.\u00a0 The keyguard fits within the keyguard frame.\u00a0 The “mounting method” options apply to the keyguard frame (click on an image to enlarge it):<\/p>\n\n\n\n\n\n\n\n\n
\"\"<\/a><\/td>\n<\/tr>\n
no mount<\/td>\n<\/tr>\n
\"\"<\/a><\/td>\n\"\"<\/a><\/td>\n<\/tr>\n
clip-on straps<\/td>\nshelf<\/td>\n<\/tr>\n
\"\"<\/a><\/td>\n\"\"<\/a><\/td>\n<\/tr>\n
slide-in tabs<\/td>\nraised tabs<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

The keyguard mounts within the frame using either snap-in tabs (for quickly inserting and swapping keyguards) or posts (for a flip-up keyguard) (click on an image to enlarge it):<\/p>\n\n\n\n\n
\"\"<\/a><\/td>\n\"\"<\/a><\/td>\n<\/tr>\n
snap-in tabs<\/td>\nposts<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u00a0<\/p>\n

Replacing a Screen Protector<\/h1>\n

\"\"<\/a><\/p>\n

Tablet cases often include screen protectors.\u00a0 Based on its name, you’d think the purpose of the screen protector is to protect the screen from scratches and breakage.\u00a0 However, most tablet screens are very resistant to scratches, and any force strong enough to crack an “unprotected” screen will probably crack a “screen protected” screen.\u00a0 What the screen protector is more effective at doing is preventing liquids that have dripped onto the case from reaching the electronics of the tablet inside.\u00a0 This is done by sealing a thin sheet of transparent plastic to a thick, rigid frame.\u00a0 The plastic sheet and frame act like a shallow bowl to hold any liquid dripped into it.\u00a0<\/p>\n

Screen protectors have long been the bane of keyguards because the opening in the screen protector’s frame is often only slightly larger than the tablet screen.\u00a0<\/p>\n

\"\"<\/a><\/p>\n

In order to expose as much of the screen as possible, the keyguard must have a very thin perimeter.\u00a0 This makes the keyguard more fragile and greatly limits the mounting options.\u00a0 The thin perimeter means there’s very little plastic for the attachment of micro-suction tape.\u00a0 The rigid frame means that you can’t wedge the keyguard into place.\u00a0 Finally, the clear plastic sheet is sealed to the frame, so you can’t insert slide-in tabs under the edge of the frame.\u00a0 You’d first have to break the seal on the screen protector and that would void any implied warranty offered by the case manufacturer.<\/p>\n

We’re going to look at how we might replace the screen protector that came with your case with a 3D-printed version where you can control the size of the case opening so that your keyguard can have a thicker perimeter.\u00a0 And there might be additional benefits.<\/p>\n

This method can also be used to create a screen protector for a case that didn’t come with one.\u00a0 Either the case came with a rigid frame that doesn’t have a transparent sheet of plastic attached, or the case has no rigid frame at all.<\/p>\n

The idea described on this page came from Felice Flowers.\u00a0 She wondered if it would be possible to replace the screen protector with a 3D-printed version designed to accept a fitted keyguard.\u00a0 And would it be possible to attach a sheet of transparent plastic to the underside of the custom screen protector?\u00a0<\/p>\n

It turns out that you can – and the result is quite satisfactory.<\/p>\n

The following example is for a particular case and screen protector combination.\u00a0 Your screen protector may be very different in its design and you may need to take a different approach all together.<\/em><\/p>\n

Taking a close look at a commercial screen protector<\/h2>\n

A screen protector normally attaches to the face of the tablet with some retainer clips built into the underside of the rigid frame:<\/p>\n\n\n\n
\"\"<\/a><\/td>\n\"\"<\/a><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Then the combination of screen protector and tablet slide into a rubbery case that protects the edges of the tablet if dropped.<\/p>\n

There’s no way to replicate these clips reliably with a 3D-printed replacement so we’ll look at different methods to mount the keyguard frame to the tablet.<\/p>\n

Determining the Overall Size of the Frame<\/h2>\n

The frame needs to fit within the same opening as the original screen protector.\u00a0 The most accurate way to get these measurements is to measure the original screen protector directly.\u00a0 The outer edge of the rigid frame should match the opening in the rubbery part of the case, which includes the curvature at the corners:<\/p>\n

\"\"<\/a><\/p>\n

Place these measurements in the “height of opening in case”, width of opening in case”, and “case opening corner radius” fields of the “Tablet Case” section:<\/p>\n

\"\"<\/a><\/p>\n

These will be the outer measurements for the keyguard frame.<\/p>\n

Determining the Size of the Keyguard within the Frame<\/h2>\n

The size of the keyguard that will fit inside the frame is specified in the “Keyguard Frame Info” section.\u00a0 Specifically, the keyguard height, width, and corner radius values.<\/p>\n

\"\"<\/a><\/p>\n

Let’s start with a sample keyguard we want to put into a frame.\u00a0 The size of this keyguard is determined by the values put into the “case opening” settings:<\/p>\n

\"\"<\/a><\/p>\n

Note that the keyguard has a significant amount of plastic around the outside, so it will be a good candidate for a keyguard frame.<\/p>\n

Begin by setting “have a keyguard frame” to “yes”:<\/p>\n

\"\"<\/a><\/p>\n

The display will change to show your keyguard “cut” to fit inside the frame.\u00a0<\/p>\n

\"\"<\/a><\/p>\n

Specifically, it has been cut to the “keyguard size” measurements in the “Keyguard Frame Info” section:<\/p>\n

\"\"<\/a><\/p>\n

The width is too small and the height is larger than it needs to be.\u00a0 Any increase in the width will take away from the frame.\u00a0 Similarly, any reduction in the height will be added to the frame.<\/p>\n

Here’s what the frame looks like… First set “generate” in the Keyguard Basics section to “keyguard frame”:<\/p>\n

\"\"<\/a><\/p>\n

Now the keyguard frame is displayed:<\/p>\n

\"\"<\/a><\/p>\n

Clearly, the frame needs more plastic at the top and bottom, so it will be helpful to take that plastic from the keyguard.\u00a0 It can also donate plastic to the keyguard on the left and right.<\/p>\n

You could modify the keyguard size settings and toggle back and forth between displaying the keyguard and the frame, but there’s a more efficient way.\u00a0 Set “show keyguard with frame” to “yes”.\u00a0<\/p>\n

The frame and the keyguard (in red) will both be shown:<\/p>\n

\"\"<\/a><\/p>\n

Select View > top from the menu to look at the pair from above:<\/p>\n

\"\"<\/a><\/p>\n

Because both the frame and the keyguard are displayed, you can change the keyguard size values and immediately see the effect on both components.<\/p>\n

First we’ll reduce the value of “keyguard height” from 160 to 145 which will take plastic away from the keyguard and give it to the frame:<\/p>\n

\"\"<\/a><\/p>\n

The display will immediately change to show the change:<\/p>\n

\"\"<\/a><\/p>\n

That looks workable.\u00a0 Now change the “keyguard width” from 210 to 220:<\/p>\n

\"\"<\/a><\/p>\n

The display now shows:<\/p>\n

\"\"<\/a><\/p>\n

This will work, but first, let’s see what the keyguard and frame look like from a more appropriate angle.\u00a0 Set “keyguard display angle” in “Special Actions and Settings” to “45” degrees:<\/p>\n

\"\"<\/a><\/p>\n

This is what the keyguard and frame combination looks like from that angle:<\/p>\n

\"\"<\/a><\/p>\n

The “keyguard thickness” is 4 mm (in Keyguard Basics) while the “frame thickness” in “Keyguard Frame Info” is 5 mm.\u00a0 That causes the keyguard to be inset within the frame by 1 mm.\u00a0 If that isn’t appropriate, you can change either value.\u00a0 Note that the keyguard thickness isn’t allowed to exceed the keyguard frame thickness.\u00a0<\/p>\n

If everything looks good, you will next render and export the keyguard and frame, one at a time.\u00a0 But first, you need to remove the keyguard from this view.\u00a0 \u00a0To do that, set “show keyguard with frame” to “no”.<\/a><\/p>\n

The keyguard disappears, and you’re left with the frame:<\/p>\n

\"\"<\/a><\/p>\n

Render the frame and export the design as an STL.<\/p>\n

Next, select “keyguard” again from the “generate” drop-down list, and the keyguard will display:<\/p>\n

\"\"<\/a><\/p>\n

Render and export the keyguard design.<\/p>\n

Mounting the Keyguard Frame<\/h2>\n

One way to fit the frame into the case opening is to put a shelf around the outside of the frame.\u00a0 Set “mounting method” to “Shelf” in the “Mounting Method” section:<\/p>\n

\"\"<\/a><\/p>\n

You can control the thickness and depth of the shelf in the “Shelf Info” section of options.\u00a0 You can take these measurements directly from the screen protector that came with the case (“shelf thickness” shown below):<\/p>\n

\"\"<\/a><\/p>\n

There are several other options for mounting your keyguard frame to the case: slide-in tabs, raised tabs, and clip-on straps – but among these, you’ll probably go with slide-in tabs.<\/p>\n

Set “mounting method” back to “Slide-in Tabs” as the mounting method in the “Mounting Method” section.\u00a0 Use the settings in the “Slide-in Tabs Info” section to control where the tabs go, how wide they will be, how far apart they will be, and how thick they will be.\u00a0 In this example, we’ve put tabs only on the vertical sides.\u00a0 They’re 1 mm thick, 3 mm deep, and 96 mm wide.\u00a0 By setting the distance between them to a negative 10 mm, we can make them overlap and behave as a single tab:<\/p>\n

\"\"<\/a>\u00a0<\/p>\n

Both the shelf and the wide, slide-in tabs provide a good amount of surface area for attaching a transparent sheet of plastic to the underside of the frame.<\/p>\n

Now set “generate” back to “keyguard” and design your keyguard as you normally would based on the app and grid layouts.\u00a0<\/p>\n

\"\"<\/a><\/p>\n

Case Additions<\/h3>\n

You can put instructions into the “case_additions” data structure to add more plastic to the outside edge of your screen protector – or cut openings into the screen protector by putting instructions into the “case_openings” data structure.\u00a0<\/p>\n

One thing to note is that the 0,0 location is now in the lower right corner of the raised part of the screen protector:<\/p>\n

\"\"<\/a><\/p>\n

This case has a small “crescent moon” cut-out for the home button.\u00a0 We want to fill in this space with plastic to protect the tablet as much as possible:<\/p>\n

\"\"<\/a><\/p>\n

We’ve added the following instruction to the” case_additions” data structure:<\/p>\n

\"\"<\/a><\/p>\n

Since we’re measuring relative to the lower left corner of the raised portion of the case opening protector, half-way up the left side is calculated as 127\/2 = 63.5.\u00a0 (The case opening – and keyguard frame – is 127 mm high.)<\/p>\n

This instruction has the following impact on the perimeter of the screen protector:<\/p>\n

\"\"<\/a><\/p>\n

You can learn more about adding case additions<\/a> and case openings<\/a> by following their respective links.<\/p>\n

The keyguard frame is now ready to print, and the transparent film is attached.<\/p>\n

Attaching the Plastic Sheet<\/h2>\n

Most rigid plastic sheets will probably work, though you should avoid films that are intended for putting in a laser or inkjet printer.\u00a0 Such films have a coating to help the ink adhere, which reduces the transparency of the film.\u00a0 Here’s one transparent plastic sheet<\/a> that will work.<\/p>\n

The attachment of the keyguard frame to the plastic sheet needs to be waterproof or your screen protector won’t achieve it’s primary function.\u00a0 You could try using glues or silicon caulk, but spray adhesive<\/a> works very well and is easier to apply.<\/p>\n

Begin by putting masking tape around the keyguard opening in the frame.\u00a0 Avoid putting any tape on the underside of the frame.<\/p>\n