3D-Printing and CNC-Milling

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Not 3D printed but a similar concept
Python 2.0 designed by Dirk Bonné

On 2011-04-29 Dirk Bonné posted a great and visionary idea in the Python Mailinglist. The actual follow-up discussion starts here:

A week ago I came across the reprap project (reprap.org), which is an "open source" 3D printing machine. Such a printer can print pieces of plastic, supposedly in any form as long at it is limited in size. I'm very much tempted making such a machine for my self (as winter project).

One idea I have is to build a bike (e.g. python) using the reprap. The goal would be to build a trellis-framed python, like my own bike (pythoon) and some others seen on the project page. I would still use regular steel tubing with small diameter (8-16mm), but the joints connecting those tubes would be printed plastic bits that are pressed inside of the tube. The construction process would look like this:

  • design all the joints connecting the tubes.
  • print them -> results in "inner lugs".
  • cut the metal tubes to the right length (tube cutter).
  • assemble the frame by pressing the plastic joints in the tubes.

=> at this point I would like that the bike is stiff enough to hold itself.

The next phase would strengthen the bike by wrapping uni-directional carbon fiber around the joints (like using a tape roll wrapping it around forming a "outer lug":

  • paint the tubes with a primer before wrapping the CF around
  • cut the roll of unidirectional CF in long strands about 1 cm width
  • use a brush dipping the CF with epoxy while wrapping it around the joints firmly connecting the tubes to the joints.

What I hope the advantages would be:

  • sharing: possible to share the design between people - anybody with a 3d-printer could produce a bike. It would even be possible to make a program that given some parameters can produce a custom measurements.
  • easier/quicklier: the tubes are just cu wih a plain tube cutter tool. There is much less measuring and filing involved (making a trellis frame can really be horrible - especially when brazing where precision means all).
  • easier: no need for a jig. The joints would make the frame pre-stiff enough to easily adjust the frame as a whole using a measuring stick.
  • equipement: no welding/brazing equipement needed (ok, you need a 3d printer....).

Other directions: the same process would be useful for a pure CF-bike or may be a bamboo-bike...

What is your take on the idea? Is there ny around iwth experience with 3d printing product?. Could it work? Would there be a real advantage?

DirkB

PS: with the reprap I discovered there is a 3D CAD for programmers: OpenSCAD. For those with the programming ability, it might be alternative for autocad and the like.