Looking ahead to 3-D printing

[Weltevreden SA (Dana)]

Three-dimensional (3-D) solid object printing is presently in its youth stage: showy, object-centred, and expensive. In time the technology will mature into consumer-aware innovation and affordability. This is a good time for we astro buffs to dream up the equipment that at present we can only dream about. Take eyepieces: bonding materials with different refractive dispersions directly to each other without cements or air can inspire a host of improvements, in the same way 3-element cemented ultrascopic eyepieces reduce lateral color and astigmatism in ways air/cement-spaced orthos do not. And who hasn't looked into the front of an oil-spaced apo to marvel at the nothing which reflects back? Similarly, generating an entire eyepiece in one go (or rather flow) eliminates retaining ring problems and the internal fogging that nitrogen and argon are intended to purge.

That's eyepieces. The prospect of single-element objectives with four or six internally aspherised surfaces and no contrast loss at every surface interface is (almost) enough for me to hold off purchasing the Next & Best scope that's always being touted on some forum or other—to say nothing of a ready response to the Household Budget Director who pounces on every dream scope discussion at the dinner table to remind me that the contents of female closets quickly go out of date, too.

Lots of issues come up. Would optical surfaces layered directly on each other at the molecular level need the 1/4- or 1/8-lambda surface precision of air or bonded glass? Reducing high-lambda polishing to field and eye surfaces would be a cost-cutter right there, but do the plastics that would necessarily be used for 3-D optics have the internal homogeneity that high-contrast viewing requires? Can electronic circuits be molded into their housings in a way that minimizes those cranky hand paddles and their moisture-sensitive connections to the RA and dec drives?

If we think through the improvements we want ahead of the manufacturers—maybe with a dose of optical math and design sketches thrown in—we, not they, would have the upper hand in product intros. Yes, all this is way ahead of the 3-D printing affordability curve at the moment. But isn't this the best time to dream up all the good-better-bests we can and let the manufacturing community know how many of us there are?

[g__day (Matthew)]

3d Printing is quite cheap nowadays.

There are some issues - like the kid in the US that printed an assault rifle (mind you its not (yet) printed from high carbon steel for the barrel) so firing a round through it would be disastrous.

Too imagine printing your own body parts and organ - from cells with your own DNA - so there is no rejection - that day is not too far off - biological printing.

There are folks who printed a 3D lens for a telescope -not very good results to say the least. Others tried mirror blanks, wrapped the blanks in plastic to get a parabolic, smooth surface - again not impressive results yet.

The printing layer by layer when each layer is just not down to fractions of wavelengths of visible light doesn't help telescope fabrication very much - you'd need atomic level smoothness to make mirrors and lens that way.

Still a very amazing filed has opened up! Wonder when one will be able to print a working 3D printer on a 3D printer? Scale it a nanotechnology and your have Sci-Fi's dread replicators from the Star Gate Atlantis series!

[Tandum (Robin)]

Originally Posted by g__day

3d Printing is quite cheap nowadays.

There are some issues - like the kid in the US that printed an assault rifle (mind you its not (yet) printed from high carbon steel for the barrel) so firing a round through it would be disastrous.

This is not really true, this is what the news is broadcasting. They 3D printed the receiver section of the weapon and under test it only lasted 6 rounds before self destructing.

So long as you can print armored vests you should be right

[MrB (Simon)]

Wonder when one will be able to print a working 3D printer on a 3D printer?

It is already happening... In a way.
I have seen quite a few guys print new better parts to upgrade their scratchbuilt printers.
But a fully functioning printer, hot off the printer probably isn't too far away, one hurdle is probably being able to print many different materials in one run.
For example, copper for the stator coils in the stepper/servo motors.

[acropolite (Phil)]

Wonder when one will be able to print a working 3D printer on a 3D printer?

As Simon said it's already happening, in pretty well all 3D printer kits, the plastic parts are printed on the component suppliers own 3D printers.

[Osirisra (Ken)]

I've had my Makerbot 2 printer for a while now and it is absolutely awesome! Being able to design and print anything I want is just a dream. Don't like a aspect or what to change something, no problem, just change it and print another, so cool.