why are you only allowed 12 by 24 inches of polycarbonate?

I moved this from the ask VEX forum because that is for VEX product support. I suggest that you listen to the VEX forum community and then decide if you want to post this to the Sack Attack Official Q&A forum.

It is simply the rule set in place by VEX they most likely don’t want a bot with a lexan casing around it.

I see it as part of a design challenge I guess, as much as I would like the use of more custom materials to be allowed in at least college this way we can have more challenges from all aspects.

  • Andrew

As opposed to offering reasons as to why, as that would be purely speculation, I’m going to offer my opinion to a solution for the rule. (which is obviously different :p)

INMHO, if you need more than 12" x 24" of polycarbonate, you’re probably doing something wrong. Polycarbonate is ideally used when you need something with low-friction and that is light. Also, the larger the piece you get (say 18" x 6", random numbers, don’t put me on the spot for those), the more “bendy” and flexible the polycarbonate becomes, and therefore, harder to support rigidly and less reliable. So, I suppose if you needed a bunch of those 18" x 6" sheets of polycarbonate, you would be out of luck.

However, if you’re using polycarbonate strictly as a container for sacks, you might find more luck by using aluminum plates. They won’t run as long 12.5" x 2.5", if my memory holds. Hey Team7706, do you mind sharing your experience with that?

There’s my two cents.

We find we are having to ration out the use of polycarb as we could easily use a lot more than 12" by 24". Other advantages to light and low-friction are:

  1. Low cost relative to aluminium plate.
  2. Flexibility, making it ideal for connections to parts that you don’t want to permanently bend or catch in “vigorous” game play.
  3. Transparent, so your driver has maximum vision of sacks in the intake, in the goals or on the field (behind the robot).
  4. Does not have holes in fixed positions, thus you can drill holes exactly where you need them to be.

I have no problem with the current size limit. Makes you think hard about how to best use it.

Cheers, Paul

I agree, it is a “Design Challenge” and there is little “Challenge” if you don’t have limits. The thing’s we could do with 2 more motors, or a little more polycarbonate… The fact is that my team had to think longer and harder to build a decent robot within the limits of the regulations. This is what engineering is about.

When I worked as an industrial process engineer many years ago we had to keep it simple and at or under budget. If these kid’s are going to enter the real world as engineers at some point in their lives they need to learn to keep it simple and make it economically feasible.

thanks everyone for your input :slight_smile:

We used lexan as a ground tray to pick the sacks off the ground and put in our bucket. It was very flimsy so we had to use supports on either side to keep It rigid.