It's time is coming, so why not plan ahead?

[Omega-TI]

I cannot help myself, sometimes things pop into my mind in a flash.  I'm also not afraid to toss them up against the wall to see what sticks, because something good sometimes comes out of them...

 

1) There is enough extra room on both sides of a TI console to drill a couple of holes...

2) The F18A MK2 will eventually be released.

3) The community has talented people with 3D printers.

 

So, how about a matching 3D printed top that can close to keep the dust out of the keyboard when not in use, but also contain a fairly decent sized LCD display?

 

Sure we would have to source for a compatible monitor, but I'm sure one has to be available somewhere.  Once, accomplished, drill a couple holes, insert a couple of black 3D printed pins and slip in a couple of cotter pins and you have a neat little TI with built-in closeable monitor.

[jrhodes]

Take an old TI Extensa 460 laptop and run classic99 on it? Still a TI, still has a built in screen, and still keeps dust out when closed.

[Omega-TI]

36 minutes ago, jrhodes said:

Take an old TI Extensa 460 laptop and run classic99 on it? Still a TI, still has a built in screen, and still keeps dust out when closed.

I do use Classic99 on my desktop when necessary, as I consider it the BEST TI emulator ever (my personal opinion), but nothing and I mean NOTHING (again in my opinion), beats "Real Iron".  One of the most fun aspects of the hobby for me has been seeing what kind of new stuff we can hang of the old computer and what new capabilities we can give it.  It's also kind of exciting to see photos of the different ways people have expanded their systems. I never get tired of new shots of peoples TI's as they enter the hobby and years later after they've expanded.  I owe my undying gratitude to so many guys here who've come up with some fantastic stuff that has made my 6 1/2 years here on AtariAge so enjoyable.  Without them, our little orphan would not be as popular as it's become.

[wierd_w]

The printer needed to print something that large, at the tolerances needed to accurately mate up with an injection molded case, is outside of my price-range (and probably most people's).

The 99a has a very large volume compared to most 3d printers.   It would be cheaper to design a suitable CAD model, and have it injection molded as a service. Get better product too.

 

Hinge design needs to be considered too.  Weak plastic hinge will be a problem.

 

[Omega-TI]

Yeah, I suppose you're right.  I was thinking in terms of multiple printed pieces assembled to make the whole.  For instance the sides, the top and the bottom parts of the frame which the LCD could be inserted into.  The back could be multiple pieces that slide into the frame channels.  But yeah, while cool, probably to expensive for the majority of people.  I'll consider this idea a miss.

[wierd_w]

It's more a function of "Plastic hinges wear out fast" coupled with "Yeah, the LCD can be kinda heavy".

 

There's a reason why laptop hinges are metal inside.  If you don't mind using "kitchen cabinet" type hinges, with some kind of printed force-arrester so it can't just flop/slam, that might work, but would not be very attractive... Maybe it could be concealed.. hmm..

 

Still, the tolerances to mate up with the original chassis needs injection molding.

 

(I am noticing that there are no dimensional drawings of the chassis on mainbyte, or elsewhere! I may have to remedy this!)

Edited October 26, 2019 by wierd_w

[Omega-TI]

<< THIS MONITOR >> looks kind of cute, unfortunately the connections are on the side which screws with the aesthetics.

[+FarmerPotato]

You should take the TI laptop shell, and re-make it into a TI-99/4A laptop!

 

Because I've seen it done successfully, I would go with milling Sintra if I were attempting to make any custom plastics. (Which I'm not. I have enough to do.)

 

 

3D printed parts are risky. Though I believe our hackerspace in Austin can, in our temp controlled 15" enclosure, meet the tolerance required to mate the surfaces (hinges have a bit of play too.) The thing is, they take too long, the engineering strength is not super great, and things can go wrong, ruining the batch. They are crunchy inside. I'm not a big fan.

 

Injection molding is ridiculously expensive. Fixed costs can be $5000 for a small batch run, to $50000+ for production mold. There are prototype bureaus who will give you quotes. You need their expertise to get it right.

 

As far as DIY, I have for a long time studied how to get ABS injection molding at our hackerspace, and in a reasonable budget ($10000 assuming the machine tools we already have.) The practical size is about a 3x5" aluminum mold at most, anything more is formidably difficult. (though we could mill steel, my proposal was for DIY aluminum molds.)

 

Resin molding is an alternative; you make a cast in 2-part epoxy, or mill out a mold cavity in cheap aluminum, and pour resin into it. Products are heavy.

 

Subtractive machining is quite viable. You can mill large ABS or PVC pieces. Large ABS blocks get to be quite expensive, but see Sintra below. Delrin or HDPE are not what you want in a laptop.

 

You can construct curved shells by heat-forming 3mm acrylic. I've bent acrylic into 60 degree angled boxes, using laser-origami-folding on a cardboard+acrylic form, then more simply using just the hot air gun and a form. It's very satisfying and beautiful. But it's still a thin (3mm) shell with geometric plane surfaces, some curves maybe. And you have to get the corners perfect to join with solvent. Still this is a cut above the average acrylic box. 

 

[Disclaimer: I encourage everybody to use lasers for everything... tragedy ensues. Don't ask about the tortilla, the laser-carmelized sugar cookies, or PCB prototypes, because I got all those banned. Don't ask about the stench of burning flesh (leather not banned). DO ask about stencils in safe materials!]

 

Vacuum forming is not so great for more than very thin shells (1mm PVC) but is quite inexpensive. You make a plaster form, and build a vacuum table. Good for face masks anyway.

 

 

 

 

Let's consider what today's modders are doing.

 

1. Ben Heck for a long time has made custom laptops and portables by milling and painting SINTRA. This is a rigid, expanded PVC foam with excellent milling properties. 

 

Here's one of his, a C64, though I know he has many many such beauties. I don't know WHY no one has ever paid him to do a TI-99/4A.

 

https://www.benheck.com/commodore-64-original-hardware-laptop/

 

2. BitBuilt is a hacker collective that re-makes game consoles into portables with LCDs. They mostly use 3D printing for their shells of GameBoys, portable Wii and PS/4. I saw them make a complete Wii portable in 24 hours last year at MGC. (I joked that they had everything but Ben Heck... and magically, there he was, haunting the corner wearing his "Grainger Things" T-shirt.)
 

The End of this post

 

My answer to custom plastics is to just do what Ben does, mill Sintra. I've tried milling ABS and other plastics without getting a solution (affordable + quality). Shit, I think I'm committing to make a proof of concept. Just what I need, another project. They sell Sintra next door to the hackerspace...