[python] Re: crazy idea?

  • From: r.mccrady@xxxxxxxxxxx
  • To: python@xxxxxxxxxxxxx
  • Date: Wed, 4 May 2011 07:27:09 +0000 (UTC)

Here's some inspiration on building your own 3D printer: 
http://www.channels.com/episodes/show/13163222/Extreme-DIY-Homemade-3D-Printer?page=5
 
Good luck with that. 

-Rod McCrady 

----- Original Message ----- 
From: "Dirk Bonné" <dirk.bonne@xxxxxxx> 
To: python@xxxxxxxxxxxxx 
Sent: Wednesday, May 4, 2011 1:09:27 AM 
Subject: [python] Re: crazy idea? 

I think my next step should be to draw the front piece of the python in 
openscad, together with the design of all the joints. And then find 
somebody with a mendel-reprap and beg him/her to print one of the more 
difficult joints. I know there is a "hackerspace" in Copenhagen 
(labitat.dk) and they have a mendel-reprap. I live in copenhagen no 
more, but could visit them once. 

Dirk 

On 02.05.2011 10:27, Jürgen Mages wrote: 
>> The printers are slow and the material is not solid, rather a mesh of 
>> small tubes. Imagine a glue-pistol you steer by hand. You cannot 
>> produce overlaps so far, so things won't be easy, i'm afraid! 
> 
> There has been some progress meanwhile: 3d printing nowadays allows 
> more freedom. 
> 
> See here: 
> 
> http://www.psfk.com/wp-content/uploads/2009/01/photos_photo1032.jpg 
> 
> So, obviously no problems with overlapping. 
> 
> Also the variety of printing material has improved a lot. 
> 
> Cheers, 
> Jürgen. 
> 
>> 
>> I came across a bamboo bike build for africa, with connected with 
>> sheetmetal 
>> joints. I think you could use something like "dyneema ropes" running 
>> diagonally 
>> across each field and reduce the torque and sheer stress greatly. In 
>> theory, the 
>> wires only take pulling forces while the beams get the pushing 
>> forces, much like 
>> moulton or pedersen designs. There was a danish company desiging a 
>> bike for puma 
>> stores with a rope beam between steering pivot and pedals which could 
>> also be 
>> used as a lock. 
>> If you can adjust the tension of the wires, you could create 
>> universal joints 
>> that are bolted together regardless of orientation. I'm not so sure 
>> about the 
>> stiffness of such a concept. But if you come up with a cage-like 
>> design with a 
>> driver inside of it, it could be working! Never stop tinkering! 
>> 
>> I have to look at this cad-tool as well. if we could agree on a free cad 
>> packages, that is available to all of us, i would set up a 
>> repository, so we can 
>> share design and otehr documents! 
>> Keep going! 
>> 
>> Greetings, 
>> DirkS 
>> 
>> 
>> "Dirk Bonné" <dirk.bonne@xxxxxxx> hat am 29. April 2011 um 14:35 
>> geschrieben: 
>> 
>>> Attached is a drawing of such joint. It would connect 3 tubes at 
>>> 90degree angles. 
>>> 
>>> 
>>> On 29.04.2011 12:21, Dirk Bonné wrote: 
>>>> 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: 
>>>> 1 design all the joints connecting the tubes. 
>>>> 2 print them -> results in "inner lugs". 
>>>> 3 cut the metal tubes to the right length (tube cutter). 
>>>> 4 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": 
>>>> 
>>>> 5 paint the tubes with a primer before wrapping the CF around 
>>>> 6 cut the roll of unidirectional CF in long strands about 1cm width 
>>>> 7 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. 
>>>> ============================================================ 
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>>>> 
>> 
>> http://dirk.steuwer.de 
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