3D printing – UV Curing Resins

Not sure where i’ll be going with this post, but here goes anyway

The CAD work progresses with the C64 mini keyboard keycaps and it’s getting close to the time where I need to be thinking about the end-game, the final product.

I can’t imagine that people will be happy with some watery grey colour, most would prefer at least some semblence to the original breadbin colours!

So, i’ve done some quite considerable googling on the subject

.Also, figured that ‘painted’ stuff used to commonly use the RAL standard to determine a standardised final colour, maybe there’s a RAL colour for commodore keycaps? (there’s one for the case!)

Turns out that finding 3D printer resin in the colour you want, isn’t easy

Also, turns out that creating your own 3D printer resin colour also, isn’t quite fully tried and tested yet

https://formlabs.com/uk/blog/medical-dyeing-coloring-sla/

a fantastic website –

https://www.3dprintedminiature.com/how-do-i-dye-resin-3d-prints/

and, many, many more websites were found, all with various anecodes, photos and information regarding colourant successes and failures

One colourant kit that kept cropping up – https://monocure3d.com.au/product-category/cmyk-pigment-set/?v=322b26af01d5 The Monocure CMYK kit.

So, it looks like if I want to create my own coloured resin, I’ll have to mix it myself.

So, where to start, and what ‘stuff’ to use to dye it?

Turns out that there’s a distinct terminology that may need to be used to figure out just what the process of colouring resin is.

https://letsresin.com/blogs/articles/epoxy-pigment-guide-what-is-a-pigment-in-resin-art

has an interesting summary.

However, for my purposes of colouring the resin..

If I use a Dye – the colours will likley be a little more ‘washed out’

so, i’ll need to use a Pigment – essentially an insoluble bunch of micro particles that sit in suspension in the resin and create a solid, opaque colour! – AKA Dark brown.

So, off to google to figure out Pigments

There’s pigments for Casting resins, Resins, Acrylics, everything…..Except, a clearly stated pigment that’s suitable for 3D printer resin!

Infact, just what is 3D printer resin? what chemicals

I found this website which goes into some depth about resin types

Also found another website that does resin pigments in a range of RAL colours

BUT, they go on about Polyester, epoxy, and I’ve no idea if those things are compatible with the Anycubic resin i’m using

Another google and, I come up with a chemicals safety sheet for some Anycubic resins –

Listed there is a key component – which ends in “acrylate” and “diacrylate”…

so, looks like it’s an acrylic / acrylate based resin? can’t say i’m a chemistry expert but an Acrylate is a group of chemicals, so i’ll run with that

I need to look for pigments suitable for use in Acrylates!

But, err, is it an Acrylated Epoxy, or an Acrylated polyester, or even something else?

2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl)-2-methylpropan-1-one is part of it!

Still clueless

https://pubchem.ncbi.nlm.nih.gov/compound/22019754#section=Depositor-Supplied-Patent-Identifiers

has some amazing information, including use in photosensitive resins

I’ve found a few websites that suggest urethrane acrylates are the go for UV resins

or, is it Acrylate polymers, or Epoxy Polymers!…….I’m leaning away from epoxy

SO, here goes – a quick google for Acrylate Polymer Pigment

I give up!. I’m just gonna buy a couple of bottles of ‘stuff’ and just see what works, This stuff seems to be recommended, and cheap, it’s brown and dyes resin, what can go wrong!

C64 Mini Keyboard Progress..

Rev 2 PCB’s have arrived – 15 of them!

Now waiting on enough Arduino Pro micros and switches to start making kits up!

Each DIY kit will probably contain the following – i’ll firm up with pictures once i’m done test populating a rev2 board

  • 70 Standard switches
  • 70 Diodes – Through hole (possible SMT option also depending on price)
  • 1 USB Hub
  • 1 PCB – Rev 2 or later
  • 1 USB cable
  • two small pieces of heatshrink tubing
  • a couple of pieces of wire
  • 1 Arduino Pro micro – Pre-programmed with QMK firmware and custom Keymaps
  • Some instructions
  • a set of FDM – Filament printed keyswitches – These probably won’t be ‘perfect’ so i’ll be chucking them in as effective freebies as I won’t be releasing the keycaps as a digital file.

About that last part – I’ve spent countless hours on creating these keycaps, and still have more to go. I’ll eventually release them as a Digital file, but for now, you’ll be able to at least use the freebies to see if new keycaps are for you.

If you wanted a professionally printed set, i’ll be arranging something with a printing bureau somehow… It’s also likely i’ll be able to source reasonably costed SLA resin prints of these…watch this space

And for the money shots…….I’ve finished the top row of key text!

Now I’ve gotten the first row done, the next three should be significantly quicker.

The text is recessed into the key by about 0.4-0.6mm – between 2 and 6 layers of 3D print, not really enough to be clearly felt – but enough to be ‘seen’

After that, there’s the optimisation for printing – Filleting the edges – trialling depths and generally finding out what actually works, looks and feels good

C64 Mini Keyboard Part 7 – More CAD -Anatomy of a keycap

C64 Keyboard Caps 5

After couple of weeks of work, I’ve finally cracked surface modelling with Fusion360 (a bit)

Here’s a bit of a step by step in creating your very own f1 Key! This is a very brief summary of what I should have done if starting from scratch, I’ve left out the trials, errors and headbanging……….

Continue reading “C64 Mini Keyboard Part 7 – More CAD -Anatomy of a keycap”