To start off, parts of this topic could be placed in several different areas (such as 3D scanners, polymer working, etc) but since it's a topic that covers several areas I think this section is the most appropriate.
Most of us here are building RepRaps for the possibility of printing our own plastic objects. I see the ideal desk setup for us RepRappers being (| Computer | RepRap | 3D Scanner | Filament Extruder (RecycleBot/similar)|). This setup would allow us to, for example, take the backs off of our TV remotes, scan them in using the scanner, and print a few backup copies in case the dog decides the original looks tasty (happened to my WiiMote). If the backs are unneeded in the future, simply recycle them into new filament and repeat.
So far, here we have the status of the 3 different parts:
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3D Printer:
-Working perfectly, many variations, well tested, what can I say?
STATUS: Working
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3D Scanner:
-David Laserscanner looks promising, but there just isn't enough community behind it all to make a perfectly working setup easily.
I see a future in which you can build a box which contains a setup for complete 3D scanning. My ideas on this are as follows:
1. A box made of cheap 1/4" plywood or similar material that is easy to come by, easily workable, and prevents light from passing through.
2. Open source RepRapped parts which can assist in making support for a sliding front panel to insert/remove objects while keeping the inside dark when the panel is down. Other parts of this would be to print gears and a stand for use with the popular Nema 17 motor in order to make a slowly rotating stand to place objects to be scanned on. Also, parts could be printed to make custom stands for the various laser/camera(s) combinations people can use.
3. The issue with many 3D scanners is the fact that they only scan one face. With the above setup in combination with software such as MeshLab, many scans of the rotating object can be made and combined into a single STL file. You would probably need to flip the object being scanned at least once so that the bottom of the object is also included.
STATUS: Experimental
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3D Filament Extruder
-RecycleBot
-FilaBot
Both of the above are good examples of attempts, but were mostly incomplete due to extruding issues (filament constant diameter, air bubbles, etc). More work needs to be put into this topic.
Points:
Air bubbles form because of air in the melted plastic being included in the extruded filament. Possible fixes to this issue would be to have the entire machine in a vacuum, spinning the melted plastic at a high rate so air bubbles float to the top, etc. I'm not that familiar with the chemical properties of plastic extrusion.
Filament is not a constant diameter. This is because of irregular pressure forcing the plastic out of the die and inconsistent cooling. Fixes for these problems would be to make sure the auger (if an auger is used) always spins at a constant speed and that the plastic filled hopper is never allowed to become empty. This means that hand cranked versions are not useable because of inconsistent turning speeds. This would require a motor with relatively high torque. A windshield wiper motor comes to mind. Also, a large hopper would be great because of the pressure of the plastic would assist with pushing plastic into the auger screw.
Also, a method needs to be made to assist in the creation of special auger screws like those used in commercial extruders. This means having an auger with a DECREASING thread depth as it gets closer to the die, increasing pressure and making a more reliable filament length. Running the extruded filament through some water also assists in a better filament, although it will probably need to be baked in an oven before use (50-60'C for 30-45 minutes) to remove moisture.
STATUS: Tested, no reliable open source design yet. Filabot looks promising, but little progress has been made in the past 3 months.
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Those were my thoughts when it comes to object replication. Having all 3 parts working would enable us to print whatever we wanted, from McDonalds happy meal models to backs of remotes, to camera sun shades, all without needing to go hunting for the files online. Do you have a nice phone case but would like it to have your name engraved? Scan it in, add your name, and print. Does your camera lens have a sun shade attachment that is visible in your picture edges? Scan it, reduce the flap sizes, and print. This would definitely open a new door to at home 3D printing and would almost certainly increase the RepRap user base.
Please let me know your thoughts on all this.
