[help] Getting a lasercut plate for a 60% board.

[rominronin]

TL;DR - On the default 60% plate size, the stabiliser holes look far too close to the edge on builder.swillkb.com, is this right or does it need 1mm extra space around the circumference?

Getting a plate cut for a matias + aekii caps project (custom layout, hand wired project). The layout: http://www.keyboard-layout-editor.com/# ... ec8bfc6ab5

When case type 'Poker 60%' is selected, the resulting plate looks as follows:


As circled above, the bottom row alps style stabiliser holes look far too close to the edge. Is this normal? Can I just order this from somewhere? Or will I need an extra 1mm along the bottom edge for this?

This is assuming a go with a standard 60% case of course.

Any help would be appreciated!

[rominronin]

Bump because seriously?

[czarek]

We can do it out of acrylic in FalbaTech (laser, high precission), or aluminium (CNC 1mm end bit - slightly less precise corners).

[pdc]

I would worry that even if it can be fabricated the small amount of material might be too weak to hold the stabilizers clipped in place. Is flipping the switches upside down an option?

[rominronin]

I would worry that even if it can be fabricated the small amount of material might be too weak to hold the stabilizers clipped in place. Is flipping the switches upside down an option?

That's what I'm worried about too. I'm hoping someone with experience here can indicate how much clearance is enough.

I also like your idea of flipping the switches upside down. I'll have to see if that's nice to type on when my aekii caps arrive though.

[emdude]

I can take a look at your plate file, but can you specify what settings you used so I can reproduce the design?

[rominronin]

I can take a look at your plate file, but can you specify what settings you used so I can reproduce the design?

Thanks emdude; here's a link to the layout: http://www.keyboard-layout-editor.com/# ... ec8bfc6ab5

Settings I used are as follows:
Switch Type: ALPS
Stabilizer Type: Alps
Case Type: Poker - 60%
Hole Diameter: 2mm
Plate Corners: 2mm

I bought the matias switches specifically to use them with aekii caps. I've ordered those as well, I've never seen or handled the caps before, so I have no idea about the profile. I'll have to wait and see...

In case they didn't work so well, I don't mind using mx switches for the 'split' space bar, and putting cherry profile caps on them. As long as the rest of the board has the aekii caps I'll be fine with that.

[emdude]

Assuming you use Lasergist, there will be no issue with the stabilizers. The distance from bottom of the stabs to the bottom of the plate is 0.2816mm, which is within the tolerances of their laser cutters. I compared that measurement to one of my 60% plate files; the respective distance is 0.1171mm. I had a plate made by Lasergist with this design myself and it turned out fine.

Other suggestions as well: 2.5mm for the plate corners would provide a better fit for most 60% cases. Also, if you go with Lasergist, setting a kerf of 0.15mm would be recommended.

[rominronin]

Thanks emdude, all of that has been noted. I have a friend working on a wooden case for me, and I've ordered the stabiliser set as well. Will post some pics when its done!

[randomist]

A general and quite rough rule of thumb for loaded geometries would be to allow 0.5 to 1 hole diameter to the edge of the work to avoid stress risers with a round hole. With a square hole the corners add stress concentrations, effectively making the geometry much weaker. If you don't apply any load around the hole then this isn't much of an issue, but dropping the plate or being a bit rough during manufacture/assembly could cause problems.

Also, edge to edge you need to double the tolerance, as both edges could vary by that much in the wrong direction. So for one edge the tolerance might be 0.1 mm, for two edges this becomes 0.2 mm, so your material at this point could be 0.08mm thick with a 0.1mm tolerance if it goes the wrong way on both edges. Then a stiff breeze breaks it. 0.1 mm is the sort of tolerance I'd work to on a manual machine like a lathe, so it might be a large over-estimate for laser cutters, where I don't really have experience. I'd still be more comfortable with more material around that edge, though.

[czarek]

If you give me DXF file I could do a test cut to actually see in practice how it works.

[rominronin]

Wow, OK! What kerf settings should I use for your cutter?

[czarek]

None please, our CAM sets it automatically depending on tool used.