Hi, my school is out of legal polycarbonate but we do have a bunch of left over change up goals. Does anyone know what type of plastic it is and if we can use the backboard pieces on our robots?
TLDR: is change up backboard plastic legal for competition use?
Any nonshatter plastic that is relatively thin and you should be fine.
if you have a pair of calipers or mics you can check for yourself. as long as it’s less than 0.07” thick and within the 12” x 24” area limit, it should be fine. i dont imagine it’s out of any exotic plastic. id check myself but i dont have my field goals anymore
The material is polycarbonate, a legal plastic according to the game manual.
Ok thanks I didn’t know if it was polycarbonate or not.
Choices for “clear plastic” are kind of limited, and those commonly available in sheet form for low-run fabrication (like VEX game pieces) are even more so.
The most common clear sheet is Acrylic (polymethylmethacrylate-PMMA, or “Plexiglas”-brand name), illegal according to the game manual because it is a shattering plastic.
A bit more expensive is polycarbonate (Lexan-brand name), which is legal.
Other clear plastics are available, but are not as common in sheet form, they are usually purchased as pellets for injection molding of extrusion: polystyrene (cheap and easy to injection mold), really brittle, but “high-impact” variations are available, clear PVC (polyvinylchloride), PET (polyethylene terephthalate- soda pop bottle plastic), and polyester. Some of these aren’t crystal clear, and some are only available in thin sheet and films (like .030” thick and under). There are others, of course…6000+ different types of plastics are available.
Remember, although polycarbonate is the most popular choice, VEX does not require clear plastic, only a non-shattering plastic .070 and under. A good alternative to Polycarbonate is ABS. I would recommend www.robosource.net for as a convenient supplier of Polycarbonate and ABS for robotics (precut into 12” x 24” sheets).
Fun fact: When designing game fields that use polycarbonate sheets, we try to make sure that they are thin enough to be VRC robot legal.
The flags in Turning Point, the backboards in Change Up, and the Platform tops in Tipping Point are all examples of plastics that are legal to be reused on a future VRC robot.
And the goals + ramps from Bank Shot! I love how this creates a lower barrier to lexan usage for newer teams.
Was there a specific reason that the turning point platforms weren’t the correct size?
Like this (MCCC U-team bot, I think)!
Platforms needed thicker plastic for strength, or the support structure would have needed redesign with more expense. There’s always economics to consider, especially when building/designing something with such a low-run production as game elements.
There are always different requirements for different field elements in different games. There was a hard set requirement that a grown adult could stand on the any of the platforms in Turning Point. I have searched for a picture of a previous engineer standing on a prototype platform but I can’t find it, so you’ll have to trust me that it did meet this requirement,
You may notice that the construction style between the TP and TiP platforms are very similar. I could get away with using thinner plastic on Tipping Points platform because we did not want to encourage people to try and stand on this unstable platform. Hence the super cute Do Not Step symbol on the edge of plastic. There was no symbol like that on the Turning Point platforms.
Don’t worry, I have it saved.
Honestly, adding that much cuteness to the field elements is illegal in some territories.
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