which is better aluminum or steel????

[SCYTE16]

which is better aluminum or steel for making an outside of a robot????

[team222badbrad]

Not sure what you mean by "angled outside"? We have used aluminum for our frames since we started building robots. Yes It bends every now and then, infact we bent team 25's steel diamond plate in 2003.
The bends we get are nothing a hammer and fire can't fix.

Here is a picture of 2004 frame:

http://www.tigertrons.com/Pictures/2...n/100_0535.JPG

Edit:
We use 1/8'' wall thickness by 1.25'' angle aluminum.

[Wayne C.]

Originally Posted by team222badbrad

Not sure what you mean by "angled outside"? We have used aluminum for our frames since we started building robots. Yes It bends every now and then, infact we bent team 25's steel diamond plate in 2003.

Actually Brad- the diamond plate we used is aluminum. Steel is too heavy.

Man- I didn't know we were that much of a target..... ; )

WC

[Doug G]

For those who say welding steel is harder than aluminum - are you crazy? Maybe I'm doing something wrong? Aluminum conducts the heat far quicker than steel, which makes it tricky to get that TIG weld just right. When I TIG steel material, the puddle stays put and you don't have to constantly play with the pedal as much.

Also, plan your weight carefully so you don't have to deal with lightening holes. I know some teams have resources to mill several hundred holes in their frame, but spending hours and maybe days drilling and milling holes is probably not a good use of time. We made a change last year from a two level frame to a single level frame and instead of just using 1x1 box aluminum everywhere, we switched to using C-channel for the internal struts of the frame and just kept the box material around the perimeter. We also better planned our use of 1/16" thick aluminum for the non-stressed parts of the robot. Also we switched to nylon hubbed sprockets where possible. How nice it was to have our robot done days ahead of the deadline and 9 pounds underweight.

[Joe Ross]

I suggest that you come up with a list of attributes that you think are important for the frame of a robot. Then you can compare each one on an attribute by attribute basis.

Strength and cost are two possible attributes, but there are many more that you can compare.

There isn't a correct answer for your question. That's why you need to break it down into smaller steps.

[NotaNerd]

Not only is is just a factor of strength and cost, but also weight. You need to figure out if any parts of your robot will undergo tension, compression, or excess stress. Then, begin assigning materials to sections. To other way is to use what you have where you can use it

[The Cyborg]

Our team mostly uses aluminum on our robots, but for things that fall under great stress, like hooks, latches, and wheels, we use steel.

Aluminum is durable, lightweight material that can be easily cut, drilled into, and be bended into certain angles and shapes; not to mention it is inexpensive and abundant. But aluminum can also break under high stress and can also wear down more easily than steel.

Steel in incredibly strong, and can not bend as easily as aluminum. But, however, steel can not be cut or drilled as easily as aluminum. Steel is also heavy, and can be good for balancing your robot, but don't use too much! Steel is also expensive, making a 4X4 sheet cost about $40! The major factor, however, is that steel can rust, and can eventually break down after a long while; so if you are planning to use a robot for a long time, I suggest using as much aluminum as possible.

[Arefin Bari]

there is only one thing i can say...

Aluminum is way cheaper... Steel is way stronger and heavier. Most of the teams in FIRST uses Aluminum on their robot. this past year my team has used Steel gears for the transmission. but my suggestion would be use harden aluminum for gears and aluminum to build your robot. Aluminum gives you the option to play with weights. good luck.

[Joe Ross]

Originally Posted by Arefin Bari

Aluminum is way cheaper...

Nope. Steel angle is about half the price of aluminum angle.

[Arefin Bari]

Originally Posted by Joe Ross

Nope. Steel angle is about half the price of aluminum angle.

Joe's right... i was debating about it... i should have researched before i posted... sorry...

[George1902]

There was some really good discussion in this thread.

Enjoy! =-]

[Tytus Gerrish]

steel is cheaper, stronger, and comes in a variatiy of shapes sizes hardnesses and flavors

[Bill Gold]

Originally Posted by Tytus Gerrish

steel is cheaper, stronger, and comes in a variatiy of shapes sizes hardnesses and flavors

It's also denser than aluminum. Aluminum also comes in "a variety of shapes, sizes, and hardnesses,” so that shouldn’t be any reason to choose steel over aluminum as your material of choice.

If you’re not into using something like 80/20 (or other comparable “erector set” materials) I would suggest a basic frame be made out of something like 1” x 1” x 0.125” thick or 1” x 2” x 0.125” thick aluminum tubing. Portions of the frame that you would assume wouldn’t be exposed to much stress can probably be made out of .0625” thick aluminum tubing. You can decrease the weight of your frame and other components by drilling lightening holes in the tubing, as well.

A good example would be the robot I worked on last year.

Picture 1
Picture 2
Picture 3

The lower and upper arms were 3" x 3" x 0.125" aluminum tubing and the gripper portions were 1" x1" x 0.125" aluminum tubing. We saved a lot of weight with those holes.

I would second George's suggestion that you read the thread he has linked in his post above, if you haven't already. It’s always good to see your posts, George. It feels like such a long time since the Tigerbolt days. I hope everything’s going well for you, man.



-Bill

[Bcahn836]

Aluminum is also easier to work with, i know not many machines in our shop can handle steel. Plus as mentioned before it is much lighter. We have used aluminum on all three of our robots and we have had no problems.

[SCYTE16]

thnx for the help everybody!!!!