C64 Mini Keyboard – More CAD

The first mediocre print!

It’s taking way too long, but I think I now have the lettering ‘just right’ – at least on the screen.

This was printed a bit too hastily at 0.08mm layer height on an Ender 3 printer. I’d used a brand new roll of untested filament and didn’t bother changing any settings. – it’s dimensionally ‘spot on’..

I’ve purchased a 0.2mm nozzle for my next trial , it’ll take ages but i’m hoping that those fine details on the characters come out a little better.

Why it’s taking so long……..

I’m learning as I go. I’m ‘tracing’ letters i’m finding on the net, creating them as a new sketch along the whole rows. There’s 4 differently angled rows so each needs to be extruded in a different direction to ‘cut’ the key.

This first run matches the C64 keyboard font as close as I can get. I’ll then ‘archive’ this layout for future use and create a second ‘3D print’ version.

This version will forgo the accuracy of the font and make features much wider, more rounded to allow the characters to come out better once 3D printed. The complex ones like ‘run stop’ won’t ever come out great on a standard filament printer, but the letters already come out pretty good…that’s a win for me!

a full keyboard!

The full keyboard is above – and you can see part of one of the adaptors i’m designing to click them onto the keyswitches. each keycap is hollow. that small grey part will sit inside the keycap

Where the time’s being spent…..

And finally – part of what’s taking so long.

Each key/character is taking on average about 1/2 an hour to an hour to design. Lets say 45 minutes.

65 keys to label

That’s a LOT of minutes…and i’m only getting an hour or two every few nights – a good solid weekend ‘free’ would be great and have this sorted.

On top of that labelling (which is now finished) I have to try to make each letter more legible and easier to 3D print. Generally that means ‘bevels’ everywhere – you can see above that i’ve done ‘Run Stop’ and ‘Shift Lock’ but SHIFT is still to do….it’s not as easy either as ‘copy, paste’ the Shift from Shift lock – that’s a different sized font on a different sketch plane.

Just one example of the issues I’m seeing…The Letter B

The Letter B – trying to create a fillet – rounding off the edges

The Letter B above has an issue with the geometry – just by the 0.1 – there’s a part internally up towards the arrow that shouldn’t be there – that’ll could play havoc with a slicer when set to really small layer heights

B – Alternate view

But, the Fillet also creates a zero thickness surface which looks unsightly and will probably cause issues if I don’t correct it now

So, Back to the sketch

Letter B – The Sketch

As you can see, i’ve kept the characters with few (if any) constraints. this way has been easier to freehand and eyeball as I can drag stuff around till it looks right by ‘locking and unlocking’ lines. most constraints used to create right angles, etc have been removed after to help with the process of making it 3D

Anyways, the ‘issue’ with the fillet seems to be around the place where the two control point splines meet – i’ve highlighted one in blue above.

I re-coincide each spline (have found deleting and un-deleting works, as well as hitting coincident )

That change should hopefully roll back up the timeline to allow me to make the fillet work.

To Create the key lettering I the character by 1mm elsewhere in my workspace, then move it to over the key.

Then extrude the face of the character into the key and ‘cut’ ….

this may seem odd, but it’s a really quick and easy way of consistently creating cutouts on a row of keys and making quick changes later.

That didn’t work, so, jump into surface mode – delete the entire inner arc of the B. Re-create the arc as a ‘patch’. Stitch together the lower part of the B. Then stich the whole keycap, then re-apply fillet and…..Voila…..3/4 an hour later, one filleted B…And a learned workflow if the same thing happens on another key!

Note, as-is, the keyboard fonts are a bit innacurate. I’ve sized everything based upon the smallest characters that need to fit – i.e. run stop, etc. The individual letters could be bigger – but any bigger and they’d look too big compared to those……….

Next steps,

DFM – Design for manufacture.

Just because you design a 3x2mm hole, doesn’t mean it’ll print at 3×2. Generally Filament printers do outer perimeters a little larger, inner perimeters a little smaller. The first few tests i’ve done now prove this. so, After a few months of ‘out of the box working’ on my Ender, I’ve finally gotta bite the bullet and calibrate it. The plan is to create an offset in the CAD file so that I still design the holes accurately based on measurement, BUT, can add a accurate ‘calibration figure’ Fudge figure to make them a little larger or smaller as necessary.

Right now my Printer is doing slightly oval prints – which should be easy enough to sort out if my D9 Adventures were anything to go by

Author: bleughbleugh

Early Fourties, Wife, two kids in primary school. Both of us work full time...3 years now Back in Blighty after a decade away...It's a new country for everyone! Still finding time to tinker!

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