Producing one's own calculator keys?

[n3mmr]

Could one produce one's own keys and key-top labels?
How? 3d printing? Casting? Whittling?

[blackjetrock]

(07-25-2023 10:53 AM)n3mmr Wrote:  Could one produce one's own keys and key-top labels?
How? 3d printing? Casting? Whittling?

I'm also interested in making calculator keys. I made English keys for a MK-52:

https://youtu.be/7eO5XgGStMQ

These were 3D FDM printed on a linked frame, then I transferred the print bed to a CNC
machine and engraved the keytop legends. The frame was a good way to hold the keys
and also align them, although the alignment wasn't perfect and I had quite a few engraving
'misses'. The keys were then removed from the frame and hand finished a bit and then
I filled the engraved legends with white air-dry clay.

They looks OK, the tops are better than the sides which look FDM 3D printed. I don't know
how well the clay will stand up to use as I don't use the calculator much.

I think resin 3D printing would lead to much better keys, which could probably be made
without needing the engraving step that I used. You'd still need some way to colour the
legends, though.

I think, with a bit of experimentation I could machine keys from a sheet of acrylic and engrave
the legends as part of the same process. That would be what I would try if I needed another set.
You'd then have a cleaner side to the key. A lot of keys require features to hold them into the
keyboard, like a ridge around the base. This should be able to be CNC'd as well.

Andrew

[Jeff_Birt]

Your video is set to private so nobody can see it

[blackjetrock]

(07-25-2023 03:24 PM)Jeff_Birt Wrote:  Your video is set to private so nobody can see it

Oh yes. Fixed now

[n3mmr]

Blackjetrock, that is fascinating!

You must have a lot of interesting machines in your workshop!

[revwillie]

I've only owned my 3d printer for less than a year.

One of my goals was to try and make enclosures with keypads for some DIY calculator kits but I'm finding it more challenging than I initially expected.

Things are improving rapidly and if you have the money for a multi-material setup with a very small nozzle, it might be possible to FDM print overlays and key tops in one shot. When I tried slicing some STL files modified in Prusa Slicer with added text features, the preview was not really legible. What I mean is that key and overlay label text won't make sense if printed at the necessary scale. That's with a 0.4mm nozzle defined in the config.

In summary, I think it's possible with either a high-resolution resin printer or a newer FDM printer that has a small nozzle. I've been persuing this idea but I am still a 3d printing newbie making a lot of mistakes and learning along the way. https://www.thingiverse.com/thing:3723561

[Jeff_Birt]

One could use the laminated used in sign making for the key tops. This has a thin top layer that you V carve through to reveal the layer of plastic underneath. The cap would have to then be inset into a key body. All together a lot of work.

Filling like blackjetrock did is probably the most workable idea. Even if the filling is messy, you can sand or mill the top of the key to reveal a nice even surface. A resin printer would work well for keys.

[mfleming]

Modelers have long used decals to provide lettering and other markings on scale models. A thin layer of clear lacquer can be applied for protection. Decal paper for inkjet printers can be found at hobby shops or online at Amazon.

HP used this approach on some calculator models as some collectors have ruefully found when over aggressively cleaning a new find

[blackjetrock]

(07-26-2023 06:53 AM)n3mmr Wrote:  Blackjetrock, that is fascinating!

You must have a lot of interesting machines in your workshop!

I have a few 3D printers and a CNC engraver that is capable of cnc machining softer metals, albeit quite slowly. That's not been a problem, though, as I set it up and let it run while I do something else. At times I've had 2 3d printers and the CNC engraver running simultaneously. Quite a time multiplier.

I think my best option (as I don't have a resin printer, and don't really want one due to the resin aspect) is to machine the shape of the keys out of nylon or acrylic and engrave the top in one go. I didn't do that for the MK52 as I didn't have the CAM software available. I usually use either tools I've written or freeware and at the time neither could do what I needed. I think I could update one of the tools I created to do what I need now, though. The problem with CNCing the keys is if you need an undercut. The machine I have is only 3D (plus a turning option, but that doesn't really help) so can't do an undercut.
I'll have to have a go sometime.

[blackjetrock]

(07-26-2023 11:34 PM)Jeff_Birt Wrote:  One could use the laminated used in sign making for the key tops. This has a thin top layer that you V carve through to reveal the layer of plastic underneath. The cap would have to then be inset into a key body. All together a lot of work.

Filling like blackjetrock did is probably the most workable idea. Even if the filling is messy, you can sand or mill the top of the key to reveal a nice even surface. A resin printer would work well for keys.

I've used the classic type of this material ( the name eludes me). It is easy to machine and gives good results. It is expensive, though and the top layer is about 1mm so you need deep engraving to get lettering. I wonder if there's some material that has more like a 0.2mm mm layer on top of a, say, 10mm layer underneath?

[blackjetrock]

I'd like to know from anyone with a resin printer how durable the resin is. Would it stand up to use as a calculator key?

[Craig Bladow]

Here is the thread where I posted about the NP-25 case and keys I designed and 3D printed with a 0.4 mm nozzle. The legends were inset and not very sharp.

As a test I printed the legend on top of a layer, again with a 0.4 mm nozzle and the result was not very good. A finer nozzle and switching to PLA from PETG would also improve results.



A different technique would be to print one layer with the legends with a 0.25-0.1mm nozzle and then print the keys on top. No allowance is needed for the legends when printing the keys. I've done this to embed text in the DM-4x cases that I print, using PETG as it has better adhesion than PLA, and get good results with a 0.4 mm nozzle and bold font text.

Code:

https://www.dropbox.com/scl/fi/p4bwnwuv88kztenlof3wf/DM41X_case_HHC2022.jpg?rlkey=surnlgiz6wkg0hhqkjpoeezm9&dl=0

(For some reason I can't attach photos any more, the forum prompts for a remote URL and it is a known issue when the URL is longer than 80 characters, however, it also won't accept a URL from a URL shortening service.)

[Jeff_Birt]

(07-27-2023 03:45 PM)blackjetrock Wrote:  I've used the classic type of this material ( the name eludes me). It is easy to machine and gives good results. It is expensive, though and the top layer is about 1mm so you need deep engraving to get lettering. I wonder if there's some material that has more like a 0.2mm mm layer on top of a, say, 10mm layer underneath?

This is the type of stock I have used in the past. The top layer is only 0.003" thick.

https://www.mcmaster.com/85915T36-85915T361

[Jeff_Birt]

(07-27-2023 03:46 PM)blackjetrock Wrote:  I'd like to know from anyone with a resin printer how durable the resin is. Would it stand up to use as a calculator key?

I think so. I posted in the forum sub-section section below this one about tiny plastic gears I have made with a resin printer.