Best frame building material

[Arefin Bari]

Originally Posted by Greg Needel

for teams looking to easy construction you can also use steel tubing...now before you react to say that i am crazy think about this.

a piece of carbon tube steel (1/8 wall) .5" x .5" x 36" weights 1.5 lbs

a piece of 6061 alum tube (1/8 wall) 1" x1 " x 36 " weights 1.4 lbs

the weight difference between alum and steel is not very much when the steel is half the size

for teams who want an easy material to work with without having to buy all the attachment components with extrusion, think steel. much easier to weld, much less expensive, locally available everywhere, easy to machine


you might want to consider this when looking at materials for the upcoming season

I gotta agree with greg on this one... we have used NOT STEEL but aluminum tube... as long as its welded right... you are good to go... most of the years out bots has been a pushing bot... probably at the end of the season we will see one or two bends but nothing really bad. Extrusion are good too... we have used it during 2002 season and it worked great...

[jimfortytwo]

High quality plywood is a great material to seriously consider, especially if metal fabrication is a difficulty for you. One of the great things about plywood is that it doesn't dent-- give it a hard jar and it will spring back every time. Often the plywood comes out of the season in better condition than the 1/8" wall aluminum box beams. I must admit though, for "shiny factor" our team is considering moving into a different material for next season.

[sanddrag]

Originally Posted by superbeano2004

I was curious on what is the best material for building a frame for a robot. Last year, we used 1" aluminum tubing and it did well but it was difficult to weld and it was not as strong. I see other teams using extrusion tubing and I was also curious on why extrusion so good. Thanks for your help!

Sorry but it looks like I beat you by about 2 years in starting this thread http://chiefdelphi.com/forums/showth...ssis+materials That's okay, it was buried anyhow. Brandon, perhaps we should merge? Or not?

[Paul H]

Buzz 5 (2000) used welded angle....I wasn't on the team and don't know a whole lot about Buzz 5, so I can't comment on it.

Buzz 6 (2001) was extruded aluminum. It was good, but heavy. The way it was built, it was another one of those flexible robots, you can pick up a wheel and have the other 3 on the ground. Great for the ramp.

Buzz 7 (2002) and 8 (2003) used .25" plates for side "columns", waterjetted for lightening. There was one of these on each side of the robot, and each was connected by extrusion. Each "column" had a plate, wheels/chain, and another plate, all attached rigidly. This was nice beacues the wheels were always in line, but the robot could flex. This allows for a great deal of flexibility. Like Buzz 6, you can actually pick up a wheel on Buzz 8 and the other three will still be on the ground. It worked great with the ramp, all 4 wheels were almost always on the ground.

Buzz 9 (2004) was an improvement on this design. We actually used .024 (?) sheet aluminum and High Density Polycarb (same as in our gearbox). The polycarb were the outer walls, replacing a sheet of aluminum. The inner sheet of aluminum was replaced with the sheet aluminum with flanges all around. Motor mounts were all sheet aluminum, too. Our motor pan that held all 4 motors only weighed I think a pound or so. Extrusion was still used to connect each side column, but next year I think they are using thinwall tube, which will cut down on weight even more.

Buzz9's drivetrain, with the motors, wheels, chain, and multi speed gearboxes weighed in at only about 30 something lbs. (no battery or electronics yet, though)

[Andy A.]

I'll toss in a vote for plywood, not as the best all around material, but certainly as the least recognized.

Aside from being cheap, easy to manufacture, extremely forgiving yet rigid and easy to replace, it can be very aesthetically pleasing.

A concern though is that a Wooden frame can 'get in the way', since it is going to probably be bulkier and in larger pieces then anything else. You just have to get out of the mentality of using the frame as a place to bolt things and think of it more as a subsystem all it's self that has to be integrated with the others. Once you do you have something that looks more like a car (in the sense that it's a single machine and not a collection of machines) and less like a Frankenstein monster (for lack of a better term).

Yes, I can already hear the 'form follows function' crowd, but hey... I like good Nordic plywood. Theres just something about a bot with a real form instead of these extruded boxes with lexan panels. A properly done wooden frame has elegance.

-Andy A.

[team222badbrad]

We have always used angle aluminum. We have used anything between 1.25" to 1.5".

It tends to hold up pretty well. We occasionally get a few dents/bends. Nothing that cannot be easily fixed.

Our 2003 machine (rectangle) was probably our strongest. Even 25 couldn't dent us. We dented them.... The only thing that could have dented our 2003 machine was the shippers.... (Long story)

It was at the Rutgers Regional and on pratice day our bot ended up arriving halfway into the day. Then we open up our crate and notice everything was messed up. Controls broken, batteries all over, tools everywhere, and pieces of the robot inside. Practice day was gone... Eventually we got everything working for friday. The must have dropped it or flipped it some how.

[Jake177]

For a few years, 177 used 80x20 aluminum as a frame material. Our engineers refered to it as an adult's erector set. The pieces fit together easily and quickly without any welding, and it is very easy to change the fram if you decide that you want to mount something in a different place. Since you can assemble a base fairly quickly it gives your drivers more time to practice.

[Alan Ing]

Team 368 sat out last year but is back for 2005.

Anyway we have had great success using Bosch 30 x 30. As mentioned by others it is extremely easy to work with and allows you to construct all kinds of stuff without welding (we don't have any welders on our team). Its also very strong. Driving full speed into the goals of 2002 and the countless collisions in 2003 only mars the surface of the extrusion. The only problem with this stuff is that it isn't as light as you would think it is. We always end up milling corners off of the extrusion to make weight.

This year I noticed that Bosch now has 1" extrusions. Has anyone tried this stuff? If so, how well does it hold up? Is it almost as strong as the 30 x 30? Is the weight savings worth the loss in strength? Does it flex a lot more?

We always have a limited budget so if we go with 1", we won't be able to afford to go back with the 30 x 30.

Any thoughts?

[Denman]

All of our robots we have ever made have used 1/2 inch steel box section. Its cheap, light, easy to weld and strong. Our robot stood up to me jumping up and down on it (and i am around 15 stone ) so its pretty strong. We even made a small "featherweight" for robot wars thing here once out of it. Its just really good


[rant]
One of the factors you didn't mention was price, which is a definate problem for us, we have to pay for entry and get there from uk, costing more in flights than any of the US teams (not sure about the brazilians)...

In america sponsorship is much more easy it would seem :\ its like getting blood from a rock here lol
[/rant]

[Greg Needel]

Originally Posted by Denman

All of our robots we have ever made have used 1/2 inch steel box section. Its cheap, light, easy to weld and strong. Our robot stood up to me jumping up and down on it (and i am around 15 stone ) so its pretty strong. We even made a small "featherweight" for robot wars thing here once out of it. Its just really good

this is exactly what i was talking about....for those teams which are stuck on extrustion you will save atleast have the cost, and the weight,

[dddriveman]

80/20 is the best material hands down. It is so light and easy to work with that you can have a working frame in as little as three hours if not less.

[sburro]

Originally Posted by Sean Schuff

Another benefit of the FRP is that when it takes a hit it flexes and returns to it's original shape. Aluminum, on the other hand, won't return if bent too far.

If you're looking for a different material to use on your robot, consider FRP. It's pretty sweet stuff!

Sean

Can you tell us a little more? maybe pics and how it is made?

[Rickertsen2]

Originally Posted by Sean Schuff

For connections we machined unistrut down to a size that allowed us to slip it in the end of the FRP with just a snug interference fit and used unistrut fasteners to tie it all together.
Sean

Vould you please elaborate on this a little bit? first off is does FRP come shaped like a panel? Or rods? tubes? what? I'm a little confused. It sounds to me liek you are saying it is a panel and you put in in the T-slot of unistrut?

[Greg Needel]

FRP = fiber-reinforced polymer...essentially it is aluminum that has fiberglass or some other composite in the material which gives it the characteristics of both metal and fiber....I'm not sure but this seems like it could get expensive

[Jaine Perotti]

Originally Posted by jimfortytwo

High quality plywood is a great material to seriously consider, especially if metal fabrication is a difficulty for you. One of the great things about plywood is that it doesn't dent-- give it a hard jar and it will spring back every time. Often the plywood comes out of the season in better condition than the 1/8" wall aluminum box beams. I must admit though, for "shiny factor" our team is considering moving into a different material for next season.

I agree with you about the effectiveness of plywood.
We used plywood for the bottom of the inside of our chassis for the past two years. Our first year's robot is constructed completely out of plywood.
Plywood is good for two reasons: it absorbs shock well w/o denting and is lightweight -- lighter than lexan or aluminum of the same thickness. Plywood is also a common and inexpensive material, compared to lexan and aluminum extrusion. Plywood provides a good mounting surface too.
As for the "shiny factor", plywood is easy to paint and decorate on a low budget Have any artists on your team? You can make this stuff look good.

We have used a variety of aluminum frame materials. This year's robot used the hollow aluminum beams that came in the kit. We drilled holes (but not to many to make it too weak) to take weight out of the frame. These worked very well. No dents or anything.