[python] Re: crazy idea?
- From: Dirk Bonné <dirk.bonne@xxxxxxx>
- To: python@xxxxxxxxxxxxx
- Date: Wed, 04 May 2011 09:09:27 +0200
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.
>>>> ============================================================
>>>>
>>>> This is the Python Mailinglist
>>>>
>>>> //www.freelists.org/list/python
>>>>
>>>> Listmaster: Jürgen Mages jmages@xxxxxx
>>>>
>>>> To unsubscribe send an empty mail to
>>>> python-request@xxxxxxxxxxxxx
>>>> with 'unsubscribe' in the subject field.
>>>>
>>>> ============================================================
>>>>
>>>>
>>
>> http://dirk.steuwer.de
>
> ============================================================
>
> This is the Python Mailinglist
>
> //www.freelists.org/list/python
>
> Listmaster: Jürgen Mages jmages@xxxxxx
>
> To unsubscribe send an empty mail to python-request@xxxxxxxxxxxxx
> with 'unsubscribe' in the subject field.
>
> ============================================================
>
>
============================================================
This is the Python Mailinglist
//www.freelists.org/list/python
Listmaster: Jürgen Mages jmages@xxxxxx
To unsubscribe send an empty mail to
python-request@xxxxxxxxxxxxx
with 'unsubscribe' in the subject field.
============================================================
Other related posts:
