[FTC]: Rev 6 of Game Manual Changes Rules on Plastic and Aluminum Sheets

[PhilBot]

Originally Posted by aklego

JesseK,

I still think it is simply an issue of poor wording in an attempt to clear up a previous ambiguity.

Based on past Q&A, a simpler rewording would have just specified the total # square inches allowed, and left off the whole 24x24 specification. That was confusing from the get-go.

Hard to beleive that whoever made that last change had read all the Q&A's.

Having to ensure that all our pieces can come from one sheet of 24x24 will mean dissasembling the entire robot. I'd ask for clarification, but TIMS is down so I don't know my password

[Madison]

I have not kept up on the Q&A forum, so clarifications there allowing parts to be cut from more than one sheet are a surprise to me. I think the wording of Rev. 6 of the manual makes the most sense and should remain, but our robots were designed with that restriction in mind from the beginning.

The maximum dimension of 24" is an important limitation, as it prevents teams from, say, using a piece of stock that is 1" wide and 576" long.

[charrisTTI]

Following are my as yet unanswered (and therefore not visible) posts to the FTC Forum:

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On the basis of the answers to questions #3, #11, & #22:

#3 answered on 9/22/09
A: the total area of each type of material must be less than or equal to 576 sq. in. (i.e., 24" x 24") and the individual pieces must be able to be cut from a 24"x24" piece of raw material.

#11 answered on 9/29/09
A: Yes, as long an the total area and max. dimensions don't violate the limits

#22 answered on 10/8/09
A: Teams may use aluminum sheet with the following restrictions:
- Total combined area of all aluminum sheet is 24” x 24” in area (576 sq. inches) or less.
- No piece of aluminum may exceed 24 inches in length.
- Sheet thickness shall be 0.0625” or less.
- All of the pieces of aluminum sheet used in robot construction do not have to be cut out of the same 24” x 24” sheet of aluminum as long as the total area and maximum length rules are not violated.

over the past 2 months the students designed a ball lifting mechanism utilizing a PETG plastic cylinder 8" in diameter and 16" in height. The cylinder is constructed from two pieces of PETG 12.5" x 16". Total area is 400 square inches and all dimensions are less than 24". However, the two pieces had to be cut from two different 24x24 in sheets. This was not a problem based upon the above answers. Now, in R6 of the Game Manual just recently posted the words "Not more than 1" were added to the rules pertaining to the plastic and aluminum sheets. It seems unfair to make this rule change at this late date after competitions have already been held. This is not a clarification, but a major change which contradicts not just one but three official forum answers that have been posted for more than two months. Please advise what I should tell the students about their completely fabricated and working design

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Rev 6 rule changes to <R5> c.1, c.2, c.3, c.4, and c.6 also directly contradict answer to post #9 in Other Parts and Materials

Quote:
Originally Posted by 2009FTC3658
Q: Is it possible to use more than one thickness of a particular material as long as the total area for that material does not exceed 576 sq. in. or the extent constraint? For example, use a 12" x 24" x 0.0625 sheet of Polycarbonite and a 12 x 24 x 0.093 sheet of Polycarbonite. This would constitute a total for Polycarbonite of 24" x 24" that is within the thickness limit.
A: Yes.
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[PhilBot]

Woo Hoo.

Manual update 7 has just been posted and the latest Q&A rulings have been re-instated.... specifically:

1. Polycarbonate plastic sheet (e.g. Lexan), not to exceed 576 sq. inches total area, 24” maximum dimension, and not greater than 0.10" thick.

2. Kydex plastic sheet, not to exceed 576 sq. inches total area, 24” maximum dimension, and not greater than 0.040” thick (1 mm).

3. ABS plastic sheet, not to exceed 576 sq. inches total area, 24” maximum dimension, and not greater than 0.0625” thick.

4. PETG sheet (aka Vivak® Copolyester Sheet) not to exceed 576 sq. inches total area, 24” maximum dimension, and not greater than 0.080” thick.

Much clearer.

[J93Wagner]

Originally Posted by PhilBot

Much clearer.

Yes, but what about Aluminum sheets?

[PhilBot]

Originally Posted by J93Wagner

Yes, but what about Aluminum sheets?

Same...

It was just further down the page.

Download it !!!!!

[Tristan Lall]

Unless they mean to restrict diagonals, they probably shouldn't use the confusing term "maximum dimension". (It would probably have been better to have said something about each part's perimeter being traced within its own theoretical 24 in side length square, and a total area within all perimeters of less than 576 in² per material.)