<R9> A limited amount of custom plastic is allowed. Robots may use custom-made parts cut from certain types of non-shattering plastic. It must be possible to have cut all of the plastic parts on the Robot from a single 12” x 24” sheet, up to 0.070” thick. The intent of the area / thickness constraints is to limit the number of custom plastic parts used in Robot construction, not to define an absolute volume. For example, using a sheet which is 0.035” thick does not permit two 12” x 24” sheets’ worth of parts. Plastic parts do not have to be literally cut from the same original 12” x 24” sheet. However, all individual parts must be able to “nest” or rearrange into a 12” x 24” area. A collection of parts which theoretically have a total surface area of 288 in2, but cannot be nested onto a single 12” x 24” sheet, would not be legal. See Figure 23. Plastic may be mechanically altered by cutting, drilling, bending, etc. It cannot be chemically treated, melted, or cast. Heating polycarbonate to aid in bending is acceptable. Legal plastic types include polycarbonate (Lexan), acetal monopolymer (Delrin), acetal copolymer (Acetron GP), POM (acetal), ABS, PEEK, PET, HDPE, LDPE, Nylon (all grades), Polypropylene, and FEP. Shattering plastic, such as PMMA (also called Plexiglass, Acrylic, or Perspex), is prohibited. The PET Sheet Variety Pack (276-8340), sold by VEX, is considered “plastic” in the context of this rule, and is subject to the same limitations as “off-the-shelf” plastic sheets. This rule does not apply to 3D printed plastic parts. 3D printed parts are not permitted in the VEX Robotics Competition, except as non-functional decorations (per <R12>) or as custom License Plates (per <R24>).
Figure 23: Custom plastic parts must fit within a single 12” x 24” sheet of plastic.