What Kind Of Metal Can We Use For FRC?

[GaryVoshol]

Molten metal would probably not be a good idea.

[Alan Anderson]

Originally Posted by GaryVoshol

Molten metal would probably not be a good idea.

We had some on our Overdrive robot. It passed inspection that year, but I'm not sure it would now.

[Al Skierkiewicz]

As Jon has pointed out, lead requires some serious protections for use on FRC robots and it may not be worked on in at the event. Beryllium in common industrial form is carcinogenic and in many people produces serious to fatal allergic reactions. You may have alloys such as Beryllium/copper springs or switch parts. No Beryllium oxide insulators (ceramics) though.

[JamesCH95]

Originally Posted by animenerdjohn

You could alloy your own super-strong metal too if you want!

I would love to see the fair market price for a one-off batch of "super-strong metal" in your BOM

Originally Posted by Sandvich

It doesn't actually have to be commonly available, as long as it isn't dangerous or too expensive.

I wonder how stringent their standards are for hazardous materials. Lead and beryllium come to mind. They would be harmless on a robot but dangerous to work with. So FIRST could restrict it on the grounds that it puts students at risk, while allowing COTS parts containing the materials.

From the 2013 FRC manual:

"There are many reasons for the structure of the rules, including safety, reliability, parity, creation of a reasonable design challenge, adherence to professional standards, impact on the competition, compatibility with the Kit of Parts (KOP), etc."

Emphasis mine.

Hazardous materials are, by definition, not safe. Certain risks are unavoidable (i.e. the battery). However, I doubt any team has suffered from not using a hazardous material (i.e. 'we would have won if our steel ballast was lead!' or 'our titanium/carbon-fiber mechanism failed... if only we could have used beryllium!). Don't use hazardous materials, it is neither gracious nor professional to expose other teams to potentially dangerous materials when there are plenty of other options available.

Parity, in this context, means: 'an equal playing field for all participants, regardless of their economic circumstances'. If you use a material that is not available to all teams you are violating the spirit of 'parity' in the rules, which is neither gracious nor professional.

You can lawyer the parts/materials rules all you want to try and find loopholes. The intent and spirit of the rules is to use safe and available materials to mitigate risk and unfair advantages.

[Cal578]

Originally Posted by Alan Anderson

We had some on our Overdrive robot. It passed inspection that year, but I'm not sure it would now.

Mercury?

[Alan Anderson]

Originally Posted by Cal578

Mercury?

Mercury.

[Cal578]

Originally Posted by Alan Anderson

We had some on our Overdrive robot. It passed inspection that year, but I'm not sure it would now.

Originally Posted by Alan Anderson

Mercury.

What rule has changed such that it might not pass now? I would expect that a COTS device, that has passed UL and such, would be ok.

[Andy A.]

Originally Posted by Cal578

What rule has changed such that it might not pass now? I would expect that a COTS device, that has passed UL and such, would be ok.

<R08> ROBOT parts shall not be made from hazardous materials, be unsafe, cause an unsafe condition, or interfere with the operation of other ROBOTS.

That'd be enough to give an inspector justification for nixing the above connector. Industrial mercury use is under very close scrutiny, and whether it's a commercial part or not doesn't necessarily matter anymore. My employer, for instance, wouldn't allow it unless I made a very thorough case for having no other practical option, documented a hazmat containment/cleanup plan, and an end of life disposal plan.

That's not to say the connector is illegal by default, just that it's in a gray area. I think any team wanting to use it these days would be facing a pretty hard sell with the inspectors.

[Al Skierkiewicz]

Under current rules and inspector interpretations, this rotary connector must be designed to work on moving bodies as well as providing rotary connections. Often these devices are not designed nor intended for anything but stationary rotary mechanisms. Vibration, misalignment and shock can cause these to leak and that would bring an event to a halt.