Author Topic: Building custom mechanical/support parts  (Read 1196 times)

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Offline keokeo22Topic starter

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Building custom mechanical/support parts
« on: July 08, 2011, 05:27:23 AM »
I always wanted to build a custom robot, but the main problem has always been the mechanical part. I'm able to model wood but I have no place to reconstruct my own "carpentry room" where I now live

I thought using legos or some other mechano's pieces but they are definitely not good to build custom parts like sensors hold supports or custom-shaped chassis

I also saw the rep-raps machines but I think it's too hard to build one from scratch by myself ( I need this thing to work out properly, I could consider the idea of buying one but not to build one ) and I'm unsure whether the created parts could fit to my purposes

Does someone know a better method to create custom shaped chassis / components ?
The mechanical part is what I really need to build  my own robots, the electronic/mcu/motor part is where I know how to do it.

Offline mstacho

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Re: Building custom mechanical/support parts
« Reply #1 on: July 08, 2011, 06:53:07 AM »
Well, assuming you know how to do shopwork like that, then you have the option of going to a local university/trade school, which most likely has a shop, and renting some time.  I've also heard of places that are sort of like "do it yourself garages", but for shop tools.  They do exist, although I'm not 100% sure a) what they're really called and b) if they exist in your area.

:-P Sorry, that may have been useless, but the upside is that these things do exist!
Current project: tactile sensing systems for multifingered robot hands

Offline keokeo22Topic starter

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Re: Building custom mechanical/support parts
« Reply #2 on: July 08, 2011, 07:28:11 AM »
Thank you for your reply, but my local robotic engineering department currently uses lego technic pieces to assemble robots. That's not extremely professional nor cheap or very practical, I was looking for something better (I'm in Italy by the way.. shame on these things  :( )

Offline Robot Attack

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Re: Building custom mechanical/support parts
« Reply #3 on: July 08, 2011, 07:52:56 AM »
Depending on your budget, there are a lot of options out there.
If you can afford it, you can model your parts in some CAD software then outsource them to be made for you.

3D printing (SLA) is nice for its versatility, if you can model it they can probably print it for you.
http://www.forecast-3d.com/ is my 3D printing shop of choice

If plastic isn't good enough you can have your parts machined out of aluminum.
Check out http://www.protolabs.com/ - First Cut. They have some pretty advanced automated CNC milling. Its pretty cheap too, for custom machined parts.

I am not sure if either of those shops ship to Italy, but I wouldn't be surprised if they did.

Just to give you a very rough idea it costs about $80 to have a part the size of your hand 3D printed, and about $125 to have it machined. Keep in mind those are very rough numbers. You can get quotes back from those shops or others pretty fast if you want to pursue one of those routes.

I also like to use plexiglas for the chassis of some of my bots. Design it in CAD, print out a template, stick it onto a sheet of plexi and carefully cut it out with a bandsaw or jigsaw and drill out your holes. Plexiglas glue essentially welds the different parts together, giving your chassis a really clean look if you do it with some care.

Hope this helps, best of luck :)


Offline Soeren

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Re: Building custom mechanical/support parts
« Reply #4 on: July 08, 2011, 07:58:21 AM »
Hi,

MechanoTM (or one of its clones) are fine for light work and to make sensor brackets and such, just bend the pieces if you cannot get some that match (it's very mild steel and can be bent with pliers or even by clamping the piece under a ruler or similar and just bend the free end.

If you wanna use wood, you could get scraps of plywood and square pieces of around 10..20mm square, and cut them outdoors with a small saw (almost any small saw will do for this, even a bone saw from the kitchen).

Yet another option is the plastic that you heat up under in hot water (around 60C-70C) to make it soft as clay. When it cools down it gets hard in the shape you made. It's fairly expensive though.
Regards,
Sren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline Robot Attack

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Re: Building custom mechanical/support parts
« Reply #5 on: July 08, 2011, 10:27:33 AM »
Quote
Yet another option is the plastic that you heat up under in hot water (around 60C-70C) to make it soft as clay. When it cools down it gets hard in the shape you made. It's fairly expensive though.


Its called Shapelock: http://shapelock.com/

This stuff is really great and completely reusable. I would highly recommend having some of this stuff on hand in anyones lab. Its great for instant prototyping as well as permanent parts

Offline keokeo22Topic starter

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Re: Building custom mechanical/support parts
« Reply #6 on: July 08, 2011, 12:22:18 PM »
Thank you all for your answers, anyway I think I'm going to buy a pack of shapelock.. it just sounds interesting

I'll write here if it turned out to be a great way to make robot frames / supports

Offline igor

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Re: Building custom mechanical/support parts
« Reply #7 on: July 13, 2011, 12:05:00 PM »
Quote
This stuff is really great and completely reusable. I would highly recommend having some of this stuff on hand in anyones lab. Its great for instant prototyping as well as permanent parts

How would you rate it against Aluminium, In terms of weight/strenght/rigidity?

 


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