Generational Degradation

That brings up a good question: Is the goal of this project to make a rapid prototyping machine that a human can use to make another rapid prototyping machine? That seems to be what the RepRap project is aiming for. I wasn't sure if articulated robot arms for assembly and so on were part of its scope.

They are. Everything is.

Self-assembly and daughter-assembly are separate and difficult challenges, and folk chose to go after machine-fabricated and human-assembled to begin with.

This is a good place to discuss it.
[forums.reprap.org]
VDX mentioned that he had done some work on a related subject, and might be up to putting it in the wiki.

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Philosophically, RepRap is a guerrilla movement as opposed to a tightly choreographed formal army.

If you tack up a robot arm, a robot arm is part of RepRap.

If you tack up a vase, , a vase is part of RepRap:
[reprap.org]

And so on.

Remember that you are in charge, and decide what is the most fun to work on.

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-Sebastien, RepRap.org library gnome.

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Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything!

Hi Sebastien,

> VDX mentioned that he had done some work on a
> related subject, and might be up to putting it in
> the wiki.

... i'm really busy now, but here is a related discussion and atached images with some of my then developed and used tools ... mabe helpfull?

Edited 1 time(s). Last edit at 04/29/2010 04:48AM by VDX.

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

I did think inhibition sintering sounds a little wasteful, which is why I suggested a possible inverted process whereby the part material is doped with something to enable it to take more heat energy. I am still a little curious as to why salt is needed rather than the water being enough to take energy from the surface for evaporation.

If you could avoid using salt solution and use water or maybe a magnetic medium there may be a way to dry or separate support powder for reuse.

Masking also sounds a little wasteful, but is there a way to use an LCD panel or something. A laptop screen would be a relatively cheap source of a reprap sized panel. I know there is electro photo reactive glass used in buildings to reflect heat, I was wondering if there is anything similar.

I still think this inhibition sintering sounds the forerunner so far for plastic parts, but I can see the limitations for metals. In the video I posted above the machine actually looks like something that a reprap enthusiast would have made. (I don't mean that in a negative way). Much of the technology used is available to the home builder.

... the water disperses nearly immediately in the powder and evaporates quickly if heated, so it's not enough for sintering-inhibition ... the salt crystalizes out, so a thin coating of nano-salt-crystals separates the wetted particles, even if they melt under the IR-heater ...

An LCD-mask is only usefull if the LCD isn't affected by the heat from the IR-source and don't block the radiation on the powdersurface - here i know only UV-cured epoxy what's masked with a LCD ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

VDX Wrote:
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> ...UV-cured epoxy [is] masked with a LCD

It occurred to me the other day that one might be able to replace the OEM fluorescent bulbs in a standard LCD HDTV with tanning booth UV fluorescent bulbs for this purpose. Has this idea come up before at all?

A solution to the temperature sensitivity of an LCD panel (they are very temperature sensitive. Some LCD strips are printed with calibrated temperatures to be used as a stick on temperature gauge!) you can switch to a different current display technology, DLP. The micro mirrors of a digital light pipe, or more accurately a multi-mirror device, can withstand much more intense light and heat, and still spread the heat over the surface in a controlled way. With the very short time constants for changing the mirrors from on to off or back again, they could even be sliding down the work material shining a shifting pattern constantly to only illuminate the material to be sintered. (Hey, is this a patentable idea? If the but companies make them, I want my share!) With the ability to illuminate most or all of the work surface at once, this would be a very fast buildup technique. Current DLP panels are less than an inch across, in the 1 to 1.5cm range, so optics would still be needed to spread the light (heat) around to make a larger work area. And as for whether or not they can stand the heat, just consider how hot the light must be for a 10,000 lumen projector when the light intended to fill a 12 square meter screen is all focused onto one (or three) 2 square cm panels.

This idea sounds so good I am going to start a separate thread, which we should have done long ago for the methods beyond thermoplastic FDM 3D printing

Mike

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Team Open Air
Blog Team Open Air
rocket scientists think LIGHTYEARS outside the box!

In addition to removing the horizontal movement axes by illuminating the entire layer at once, your idea also might remove the vertical movement axis. One could simply refocus the projector for each layer. The lens is moving up and down, of course, but the entire projector wouldn't need to be moved. Three caveats: refocusing instead of moving the projector would limit the build area to a sort of pyramid shape (with the top cut off at the minimum focal length), and, because the total projection surface gets progressively smaller with each layer, the layer images would need to get progressively larger to compensate. The light intensity would also increase with each layer.

Edited 3 time(s). Last edit at 05/01/2010 12:40AM by fgrams.