Cost Determination, Section 5.3.4.4

[Tristan Lall]

Originally Posted by Peter Matteson

Also the cost of the material could in fact be crippling. Remember you still have to account for the material cost in your $3500 additional materials budget.

Originally Posted by Al Skierkiwicz

As Peter stated, there are certain constraints that limit the materials. As a rule of thumb, exotic materials cannot be used. The test being are they available to everyone. If you make it will other teams be able to buy the same thing.

I'd be surprised if the cost of the resin and fabric was exceedingly high—fair market value for a couple of rolls of carbon fibre fabric and resin is only a few hundred dollars (maybe $800 USD for enough for a basic frame*). While not exactly cheap, it's a far cry from $3500. Most of the costs for custom composite work come from the labour and the tooling, both of which seem to be covered by the sponsor.

Originally Posted by Peter Matteson

Also it may just be heavier than a welded tubing or kitbot frame. I believe it was the 767 where they designed a composite tail to save weight and when all was said and done it weight virtually the same as an all aluminum one.

This is an interesting point, related to the relatively unknown, and to some degree, unpredictable failure characteristics of composite materials. Carbon fibre tends to exhibit a non-uniform response to stress; the material breaks unevenly as the plies delaminate and snap. And once it's broken, the piece is virtually always trash, because of the cracking and splintering that takes place along the material grain (it's highly anisotropic). Also, fatigue of composites is rather unpredictable—it's certainly not characterized in the same manner as steel or even aluminum. Boeing probably didn't want to take a risk with the tail, and ended up building it more strongly to withstand the significant fatigue associated with the application.

Now, given that FIRST robots are regularly subject to some pretty jarring impacts, from strange angles, I think you'd be hard-pressed to design a composite frame that could resist all manner of stresses with a very low probability of catastrophic failure. You'd certainly want to consult with an expert, in order to go this route.

Originally Posted by Gdeaver

Also beware that certain prepeg resins are toxic and I wouldn't want to use them around students. Amine allergies are enough to worry about. Putting some fiber in your robot can be a good thing.

Additionally, do not expose yourself to carbon fibre dust (e.g. from cutting). It can irritate mucous membranes (and to some degree, bare skin), and is rather worse when it gets in your lungs. Wear filter masks (and maybe coveralls) if you must cut it, and take measures to dispose of the dust.

*I haven't done the stress calculations to figure out if this "cheap" stuff is enough for your application. Maybe you'll need the aerospace-grade product, which will probably blow the bank.

[Stu Bloom]

Originally Posted by Al Skierkiewicz

As Peter stated, there are certain constraints that limit the materials. As a rule of thumb, exotic materials cannot be used. The test being are they available to everyone. If you make it will other teams be able to buy the same thing.

<R41> Additional Parts must be generally available from suppliers such that any other FIRST team, if it so
desires, may also obtain them at the same price. A specific device fabricated by a team from non-2006 Kit
materials does not have to be available to others; however, the materials it is made from must be available to
other teams.

Other teams don't have to be able to buy something that you make - they only need to be able to obtain the same raw materials (as you noted later in <R41>).

As I am certain you know Al, the rules can change from year to year. While I would be very surprised to see any change in <R41>(quoted above), it is possible. That being said, please note that rule applies to purchased parts, not something custom fabricated by a team or team sponsor. Also, could you please cite any recent rule that prohibits "exotic" materials? I know hazardous materials are prohibited, but I don't recall any recent ruling on (or definition of) exotics.

[Peter Matteson]

Originally Posted by Stu Bloom

Other teams don't have to be able to buy something that you make - they only need to be able to obtain the same raw materials (as you noted later in <R41>).

As I am certain you know Al, the rules can change from year to year. While I would be very surprised to see any change in <R41>(quoted above), it is possible. That being said, please note that rule applies to purchased parts, not something custom fabricated by a team or team sponsor. Also, could you please cite any recent rule that prohibits "exotic" materials? I know hazardous materials are prohibited, but I don't recall any recent ruling on (or definition of) exotics.

I believe Al is refering to the older rule that <R41> replaced. They relaxed it to the quoted version 3-4 years ago. Prior to that exotic materials were not allowed. Those included CF, Ti and Magnesium among others. Now as long as anyone can call a distributor and purchase it you can use it.

Also correction to my above post it was the 777 which was the first composite tail aircraft. And the reasons for the weight are as Tristan said, however do to the impacts from a FIRST game I too would tend to use thicker layups.

Also just for the fun of it a video of CF failure testing:
http://cervelo.tv/
Launch the player and watch "A crushing blow"

[Gdeaver]

I strongly believe that composite construction has a place in First robotics and I have introduced them to our team and we have had great success with them. However, getting back to the original post I'm ready to throw out the red flag and cry foul. A team that has access to high grade materials, fabrication facilities and design resource can gain an advantage over other teams. These are resources that the rest of us can not acquire at any cost. Going forward I think composites need a close look by First to determine what is allowed based on availability to all teams and the cost issue. Aerospace composite manufactures have access to types of prepegs,cloth and resins that an individual team cannot get. Their performance specs are an order of magnitude better than what can be achieved with hand lay up and materials that could be acquired by any team. As to the valuation of materials , to account for 5 yards of cloth or prepeg at 1000yd price for 5 yards would be wrong as other teams could not receive that price if they could purchase the material in cut roll pricing at all. Then the subject of tooling,molds and set up and clean up cost needs to be looked at. There are many types of composite materials that are available of the shelf. Dry cloth, room temperature cure epoxy resins, FRP and vinyl ester pultrusions, composite tubes and rods, g10 11 and 12 sheets are all available off the shelf from many manufactures and distributors and should be allowed. These issues are not the same as a team water jetting a panel vs. a team cutting the panel by hand.

[Cory]

Originally Posted by Gdeaver

to account for 5 yards of cloth or prepeg at 1000yd price for 5 yards would be wrong as other teams could not receive that price if they could purchase the material in cut roll pricing at all.

You can't do this. You have to list the value that any FIRST team would get if they called up the manufacturer and asked for the same item, so there's no shenanigans here.

Originally Posted by Gdeaver

Then the subject of tooling,molds and set up and clean up cost needs to be looked at.

Only if the company in question was not a sponsor of the FIRST team, per sec. 5.3.4.4 of the 2006 robot rules.

[KenWittlief]

Cory made me go look it up, so there is no misunderstanding (quoted below).

I think we should create a counter that increments once each time the issue of "FIRST is a Competition vs FIRST is here to inspire students" comes up during the year.

It is absolutely true that a team with a large company with many engineers and lots of expensive equipment will be able to design and build a state of the art robot, that a HS-only team with nothing but hand tools could never possibly duplicate.

But we are here to show HS students all the incredible things that can be done with technology and state of the art engineering. If Lockheed-Martin is your sponsor, then any work done by Lockheed-Martin employess is considered work done by the team. This is what we want the students on that team to experience, to be blown away when they see what a good engineer can do with $50 in materials and $1,000,000 of equipment at their disposal.

5.3.4.4 Additional Parts - Cost Determination
The "cost" of each additional item is calculated based on the following criteria, as applicable:

• The purchase price of a COTS item offered for sale by a vendor to any customer.

• The total cost (materials + labor) of an item you pay someone else to make.

Example: A team orders a custom bracket fabricated by a vendor to the team's specification. The vendor's material cost and normally charged labor rate apply.

• The fair market value of an item obtained at a discount or as a donation. Fair market value is that price at which the item would be normally offered by the supplier to other customers. Also considered to be "fair market value" are the discounted prices offered to all teams by suppliers with established relations with FIRST.

Example: Special price discounts from MSC Industrial Supply Co. and Terminal Supply Co. are being offered to all FIRST teams. The discounted purchase price of items from these sources would be used in the additional parts accounting calculations.

• The cost of raw material obtained by a team + the cost of non-team labor expended to have the material processed further. Labor provided by team members and/or by a recognized team sponsor whose employees are members of the team does not have to be included. Note: it is in the best interests of the teams and FIRST to form relationships with as many organizations as possible. Teams are encouraged to be expansive in recruiting and including organizations in their team, as that exposes more people and
organizations to FIRST. Recognizing supporting companies as sponsors of, and members in, the team is encouraged - even if the involvement of the sponsor is solely through the donation of fabrication labor.

Example: A team purchases steel bar stock for $10.00 and has it machined by a local machine shop. The machine shop is not considered a team sponsor, but donates two hours of expended labor anyway. The team must include the estimated normal cost of the labor as if it were paid to the machine shop, and add it to the $10.00.

Example: A team purchases steel bar stock for $10.00 and has it machined by a local machine shop that is a recognized sponsor of the team. The machinists are considered members of the team, so their labor costs do not apply. The total applicable cost for the part would be $10.00.

• The cost of items purchased in bulk or large quantities may be prorated on the basis of the smallest commonly available unit that satisfies the need for the item.

Example: A team purchases a 4' x 4' sheet of aluminum, but only uses a piece 10” x 10” on their robot. The team identifies a source that sells aluminum sheet in 1’ x1’ pieces. The team may cost their part on the basis of a 1’ x 1’ piece, even though they cut the piece from a larger bulk
purchase. They do not have to account for the entire 4’ x 4’ bulk purchase item.

[Gdeaver]

My point is that for certain composite materials, most teams would not have access to them at all. This is especially true for preps. The overnight refrigerated shipping charges should also be included. I checked yesterday and I could find no vendors that would ship small quantity high grade carbon dry or prep. The materials should be available to all teams. If a sponsor does make a composite structure for a team then students should be involved from start to finish. This is hard for the good stuff because they are usually done in secure areas of the plant. First sponsors should not just bring a product to their team , but should bring the technology to the team. Over the years I've seen to many first mentors having second child hoods and forgetting the kids. Composite construction is prime for abuse and shutting the kids out. Look up the definition of mentor and let that be your guide. I feel a rant coming on so I'll stop now.

[KenWittlief]

Gdeaver - I agree with you on one level. There is a real Zen thing in engineering when its just you and a piece of metal with a vice and a file in hand, or a couple wrenches and a box of gears and hardware, or a bunch of wires and connectors and a soldering iron

I love that aspect of engineering when I need to do those things. But in my experience over the years I spend 99% of my time doing drawings, schematics, specifications, writing and conducting tests

and its extreemly rare that I actually have to fabricate or assemble anything myself. I hand a drawing or send a file to someone else, and I get the fabricated part in a box a few days later. Most of the time, that is what engineers do.

In my experience as a mentor I always make sure the students have some hands-on time with some aspect of the robot build and parts fabrication, esp at the events, in the pits. I also make sure they get a realistic experience of what its like to be an engineer, where the real value of what we do happens between our ears, not fabricating and assembling things with our hands.

A good example is the capabilities of Gleason Works, the sponsor of team 578. They design and build the machines that make the gears used in most cars and trucks all over the world. They can literally hack a 1/2" slab off a one foot diameter steel 'log', put it in one of their machines, and fabricate a 12" diameter complex gear in less than 5 minutes.

It would be a crime if the team was not able to use that capability for their robot. Its great to be able to work with a student to create a drawing or cad file, and hand it off to the guys who operate those machines, then have this beautiful shiney metal gear that rings like a bell an hour later.

There are only a handfull of companies in the US that buy Gleasons $1M machines. Does that mean team 578 should not be able to utilize theirs?

[Gdeaver]

Ken,
If on week 4 or 5 a box shows up with a fancy custom widget and there was no student involvement, that is wrong. If a core group of students sat in with the design process and then watched the tech do the set up and watch that custom widget being made and then sat with the QA person and validated it, That is good, real good. However, many times this is not the case. I did allot of the work on our composites, but I had some students there mixing epoxy and helping. While we were working I beat info and the whys into their brains. At our last meeting I had a student regurgitate that info back to me during a discussion with the new students. Thats the way it should work. Bring the Tech to the students.
As to your other point, I'm on the other end. I install and repair the stuff you engineers design. Too often I am repairing or replacing parts that are poorly designed and many times it is very apparent that the designers have have little experience with the physical world. They live in the virtual world of their software. Hands on in First is a good way to help these future designers. I'm am not an engineer , I'm a reverse engineer.

[Cory]

Originally Posted by Gdeaver

Ken,
If on week 4 or 5 a box shows up with a fancy custom widget and there was no student involvement, that is wrong.

This is merely opinion. As far as FIRST is concerned, they don't care.

There are many avenues for inspiration. It is conceivable that this is one of them. Different methods work for different teams.

[Richard Wallace]

This is a really interesting topic (note to self: rate thread high).

Ken, in your 578 example above, I think the rules are clear: the gear made using Gleason's $1M machine is allowed because (1) the raw material is available to any team and it's cost won't cause the team to exceed the limit, and (2) Gleason is a recognized sponsor and its employees who fabricate the gear are considered team members.

Just as clearly, a composite frame made from raw materials that are not available to all teams at a cost that fits the rules would not be allowed.

As an analogy that fits my own team's situation: Emerson has two nice rapid prototyping machines that could be used to make parts for 931. The first is a laser cutter. My team makes good use of this because the sheet materials we cut, such as steel, acetal, and acrylic, are available to any team and not overly expensive.

The other is a 3D Systems Viper SLA machine. This beauty can make parts that are similar to Nylon 6:6 in any shape we could dream up and CAD. But we don't use it. Why? Because the parts would not be legal for FRC. That is because the the raw material is SI40 resin, which is only available in 10kg containers that cost $2500 each. So there is practically no way the team could correctly account for the material cost, even though the actual quantities used would be small.

[KenWittlief]

Originally Posted by Richard

...Just as clearly, a composite frame made from raw materials that are not available to all teams at a cost that fits the rules would not be allowed.
....

Richard - your SLA example is excellent. But I think you have reached the wrong conclusion.

Go back and read the rules I quoted from FIRST. You only have to account for the amount of material you actually use, whether it comes in 1Qt cans, 55 gallon drums, or 20,000 gallon tanker railroad cars.

My take on the availablity rule is to prevent a situation where some kids dad is a consultant, designs a custom transmission, and then 'sells' it to the team for $20 (when it cost him $2,000 to make). If he is willing to sell one for $20 he must be willing (and able) to sell 1000 for $20 each. Otherwise that team has a $2000 custom part on their robot, that was not fabricated by the team, and that $2000 must be included in the BOM total.

If the SLA goop is commercially available, then its commercially available. How big of a container it comes in, or how hard it is to transport -those are engineering issues. If you have a company that uses that material then you must be able to handle it.

Can 4 HS students buy SLA goop in a one quart can, and form parts using 3 laser pointers in a Pyrex measuring cup? No. Does that mean your team should not use it?

No.

Crank up that SLA machine this year - its one of the most awesome technologies on the face of this planet! If you can fabricate a complex plastic part with $5 worth the SLA goop, it doesnt get any more hi-tech than that.

[Jeff K.]

This is just in reply to raw materials being available to all teams.
A company known as Aerosleeves does stock different sleeves of composites and also does sell epoxy and other materials to make your own composite pieces.
Carbon Fiber Sleeves
Fiberglass Sleeves
Epoxy Filler

Another place to get Laminating Epoxy

I'm not sure about whether or not the cost would fit a team's budget, but that still depends on their design, but it is available in raw form to teams.

[Andy Baker]

Originally Posted by Gdeaver

Too often I am repairing or replacing parts that are poorly designed and many times it is very apparent that the designers have have little experience with the physical world. They live in the virtual world of their software.

We all could benefit from more experience.

I've never met an engineer who does not make mistakes. The ones who don't make many errors are not doing anything. The comments you said above about designers paints a poor picture of what they do. I would think that they would enjoy working with someone of your experience and they could learn from your efforts of making their designs better.

Now, as the case for fiberglass and usage on a FIRST robot... I don't see the big deal. What was the harm in making it legal? (as stated above, it is legal to use, if it is a commercially available product within the budgetary scope of FIRST's rules) Sure, some teams may have a very slight advantage over another team who does not have easy access to this stuff. It's not like they are using more powerful motors or they have a dramatic weight difference between their robots. When has a team with fiberglass materials on their robot had a decided advantage? There are a few teams who use it each year, and then there are teams like 71 who beat them with a PVC pipe - based design.

Also... if a team sees another team develop and use an exotic material and actually create an advantage with this usage, then LEARNING TAKES PLACE. The following year, all of those teams who were bested by the innovative team FIND A WAY to get this same resource. Either they raise money to get the same materials, or they find technical resources to keep competing with the other team.

Competition and inspiration go hand in hand. Those who inspire will be pushed to do it again and again by those who see this as a healthy competition. Those who are inspired will compete to be an inspiration to others. You can have your cake (competition) and eat it (inspire) too.

Andy B.

[sanddrag]

The way I see it is that most teams' cost accounting sheets are so poorly done that all this argument isn't even relevant. We need teams to actually do their accounting before we ask them to do it perfectly.