What materials do you most commonly use on your robots?

[bs7280]

the team I am on is still relatively new, we have been using the same stock material, 80-20, for basically everything we do (with a few exceptions). While 80-20 is a great material it can still be limited, bulky, and harder to work with. This year we have access to a cnc machine, lathe several mills, and a 3d printer, so we are especially interested in how we can fully utilize those tools.

What materials do other teams use or buy a lot of to use with their robots? I am especially interested in what some of the teams that regularly go to nationals use. I see some pictures of teams with early versions of robots constructed mostly out of 80/20 but then the final version seems to be something else entirely.

[CalTran]

Our team personally uses a lot of aluminum box tubing and recently plenty of .125 and .25 aluminum sheet.

Generally in FIRST, you'll see a lot of aluminum sheeting of various thickness.

[BBray_T1296]

We use mainly Aluminum.

For our frames, we use 1" alum box tubing (1/16" walls I think), welded into shape, which leaves an unbelievably strong and fairly lightweight piece. It is difficult to work with though, so I would not recommend our approach to a team just starting into the wonderful world of manufacturing.

On pieces that require utmost strength, like drive-train brackets and our climbing plate, we use 1/8" aluminum sheet metal, laser cut from CAD drawings and bent with a brake.

Depending on other applications, we use thinner and thinner material.

For our hopper, we used .0404, as it is very lightweight and easy to hand repair if we bashed it up a bit. For our main shooter body, we used 1/16" aluminum, which is slightly thicker, because of forces related to accelerating a Frisbee.

I think in 2011, as part of our gripper, we used .0202, but that stuff is basically paper.

For electronics, we bought a large sheet of corrugated plastic (basically plastic cardboard). You can poke through it with a screwdriver, and it is reasonably, but not uselessly, flexible. It is also very lightweight and easy to manipulate with hand tools. (on the cRIO plate in picture 1, we used a polycarb sheet for more strength.)

[jman4747]

Your number one material will most likely be aluminum. Square tube, round tube, angle, sheet from 1/16 to .25. Then plastics (mostly sheets) UHMW, lexan, and polycarbonate are our main ones. Delrin (acetal resin) is commonly used as a bearing surface (I also like white UHMW for this). All of these can be cut on the tools you have. Also don't count out 80/20 it can be more expensive but it can be worth it.

I would advise using the 3d printer for prototyping but not anything structural.

[bs7280]

One thing I forgot to add: For those who use a cnc milling machine, what do you most commonly use it for.

[jwallace15]

Here on 68 I'd say aluminum is the material we use the most. We mainly use 2X1's .125" in diameter, and 1X1's .0625" in diameter (we do occasionally use .125" 1X1s, but not .0625" 2X1's) for anything structural (chassis and supportive pieces). We'll use .0625" and .125" sheet in addition to various sizes of angled aluminum for less structural things (like the functional/moving parts in our manipulators... such as what pushed frisbees into our shooting wheel this year, and the tube that held them). There are some custom .325" thick plates in a couple places on our robot that we sent out to be water-jetted (mostly on our transmissions). We also used some Diamond Plate on our driver station and robot cart...

I've also noticed the use of lexan sheet in a lot of different places (such as the base for our electrical board, sponsor panels, guides for frisbees to fall into our disc-holding tube, and the outer wall of our shooter). I'd say that is the most commonly used material other than aluminum on my team.

As for your newer question about the use of a CNC mill, we mainly use it to accurately mill out lightening holes in chassis pieces and driver's station (only on 2X1X.125").

[MichaelBick]

Originally Posted by bs7280

One thing I forgot to add: For those who use a cnc milling machine, what do you most commonly use it for.

What kind of CNC mill do you have acess to? A decent sized machine can be used to machine almost every part on your robot. Based on your resources, I would reccomend using a combination of 2"x1" and 1"x1" aluminum box tubing. Look at teams like 254, 973, and 1538 for great examples of how to use these materials.

[Mr V]

Virtually every part on our machines is cnc milled. We use a lot of 1x1 and 1x2 tubing along with 1x1 and 2x2 angle for brackets and the like. For sheet material we mainly use polycarb and it too gets cnc milling. For milling the polycarb sheet we use double stick tape to attach it to a sacrificial piece of particle board that gets clamped to the table.

We also use the 3d printer for a number of things. We've used it to make gears for driving encoders and we use it to make pulleys for polycord loops. They basically have a 1/2 round indentation and slip over a piece of aluminum tubing. There are little tabs on each side that we use to rivet them to the tube. Those do a great job of keeping the polycord running right where we want it. We also printed a cover for a ratchet mechanism we used for our climber which had particularly sharp teeth. We incorporated a 3d version of our bear head logo on it for decoration.

[bs7280]

Originally Posted by MichaelBick

What kind of CNC mill do you have acess to? A decent sized machine can be used to machine almost every part on your robot. Based on your resources, I would reccomend using a combination of 2"x1" and 1"x1" aluminum box tubing. Look at teams like 254, 973, and 1538 for great examples of how to use these materials.

A tormach cnc milling machine. Not sure what the exact table size is but it is definitely a high quality machine.

We also have access to two grizzly mills. One is a hobby/desktop mill and another is a more professional 7 foot tall mill, also grizzly. There is also a broken bridgeport mill and grizzly lathe.

[scaryone]

Wood. Bends, before it breaks, flexes back into shape. Light weight. Plentiful and cheap. Fast curing epoxy can repair most breaks. Home depot or Lowes near most competitions.

[MichaelBick]

Originally Posted by bs7280

A tormach cnc milling machine. Not sure what the exact table size is but it is definitely a high quality machine.

We also have access to two grizzly mills. One is a hobby/desktop mill and another is a more professional 7 foot tall mill, also grizzly. There is also a broken bridgeport mill and grizzly lathe.

That is a bit on the small side, but still better than nothing . With a CNC of that size, you can still do almost any custom gearbox, all your gussets, half of you box tube, and a lot of your misc. parts. The rest should be able to be done on your other equipment.

Here are some great albums showing detailed photos of 254's 2012 and 2013 robots. I would start here to find ways of incorporating your new equipment into your manufacturing process.
https://plus.google.com/115829622106274402945/posts
https://plus.google.com/115829622106274402945/posts

As others have said before, the materials that you will find yourself using most is 1"x 1" box tube, 2"x1" box tube, 1/8" plate, and 1/4" plate

[GarroH]

We like to use a lot of aluminum, like the teams that have responded above for many of the same reasons.

One of our favorite materials, especially in the past few years, has been HDPE. This is the material we made our shooter out of and we really love it. It is fairly easy to machine and deal with. Obviously, it's not good for structural elements, but it can come in handy for a lot.

Major downside is that it can sag under its own weight. We ran into this as our shooter began to droop towards the end of the season.

Just another material to look into.

[MrForbes]

We've used all kinds of materials....steel, aluminum, fiberglass, wood, polycarbonate, carbon fiber......

And we generally build all of it without using any numerical control equipment. A band saw and drill press, tin snips, circular saw, jig saw, hack saw, and cordless drills will do it all.

It's good to see that you figured out that 80/20 is not a very good robot building material.

[ehfeinberg]

Besides the materials already mentioned, 449 tends to use a lot of delrin for many different applications. It's relatively light weight and extremely easy to machine. It is also relatively slick, so you can use it as a makeshift bearing block for low speed purposes.

[MichaelBick]

Originally Posted by MrForbes

It's good to see that you figured out that 80/20 is not a very good robot building material.

It all depends on your resources. 341 built one of the best robots in 2012 with 8020.