What kind of material will you be using for your arm/forklift?

Alright, you have your designs drawn and a some type of base built. Your ready to start constructing that beefy arm you’ve been dreaming up all week. My question to you is this what kind of material will you be using to get the strength you need with conserving as much weight as possible.

We are planning on a 4x4 1/8" thickness aluminum rectangular tube with serious trussing in it (40% of mass removed). I have seen several arms like this, and they looked plenty beefy.

Yea are main concern is weight but we have found a way out of that. We have our drive train built and with base transmission wheels compressor tanks and other basic stuff we are looking at or around 60lbs. So aluminum is out of the picture for us but it worked great last year.

Our team is looking towards the plastics as our friend for this task. We have some modified plastic material that could prove to be plenty strong.

Why is aluminum out of the picture for you?
Almost all arms I have ever seen have been made from aluminum. Whether is be angle aluminum, extruded aluminum (80-20), aluminum box tubing, or aluminum round stock.
From what I read I think you mean using a heavier stronger material such as steel. There is no reason at all to make part of the arm (or the whole) steel. It needs to move (apparently) and the lighter it is, the easier it is to power. I also think that the forces on your arm are not going to be any where near enough to require it to be made from steel. Proper use of aluminum does wonders.

Right now our arm is being designed with aluminum. But the extrusions that its made of are very common. It could be switched out for other materials as long as they come in the general shapes(square, C, L, etc.).

Most likely the team will use square aluminum tubing. It proved plenty beefy last year.

As of now we are looking at 80/20 extruded aluminum.

like last year our frame is made out of Chromali. Light as aluminum but much stronger… although very expensive… i dont even know how we paid for all of it but thats what were using this year for the frame and the prototype made now also has the arm made out of that… we need as light as possible because of all the weight from our pneumatics. we have 3 or 4 pistons to run through out the match so its gonna be heavy

last year we used triangular aluminum for our telescopic arm… idk if any of you noticed our robot last year? midwest champs? #269

We are planning to use 2" ID aluminum tube. Seems very stiff, and is also very light. McMaster Carr sells it.

Antimatter… It will help us in the never ending quest to build the bot under the weight limit. :slight_smile:

Either Al square or thinwall steel tube

Tell me more about this material. One of the kids on our team has a dad that manages a composites manufacterur. So we have been looking at some different things including carbon fiber and some other composites. Please weight is always a problem for us and we cannot afford to use alluminum this year. This is why i created this thread was to see some different composites and alloys.

I think he might have been referring to “chrome-moly,” which is a steel alloy of iron, molybdenum, chromium, and sometimes manganese. It’s a common material in high-end bicycle frames, especially in Italian or custom-made bikes. It is heavier than aluminum, per unit volume, but has better ductility, and can be brazed or welded. The lightest bicycle frames now are composites, but right behind those are aluminum and chrome-moly. It’s been a few years, but a favorite chrome-moly tubing around 1970 was Reynolds 531.

Most carbon fiber composite parts are mind-bogglingly expensive. I would be interested in hearing more about how you are thinking of fabricating composite components.

Aluminum extrusion with 24" drawer slides for a telescoping arm. Still being built. We’ll see.

1.5" square x 1/8" aluminum with some major drilling going on to it. Not too much on our arm so it should be plenty strong.

For the second year we are using some 1 and 1.25’’ aluminum tube with 1/16 wall.enough to It was strong enough to lift our robot last year and is really lightweight. It is not the easiest of things to work with because it is round, but it would be rigid enough to do anything you need to do.

We decided to just go all out this year. You can either come to play or just go home.

Part 9081K696 from McMaster was the first thing we ordered at kickoff.


He lies!

(Same as 9081K69)Titanium Grade 5 Rectangle 1" Thick, 3" Wide, 6’ Length$2,274.36 Each. Usually ships within 1 week.


If they only use about 8% of its length, can they prorate the cost? :stuck_out_tongue: