1lb Plastic Antweights - Frequently Asked Questions
Updated February 2025
- Rule 0: If in doubt, ask the event organizers for approval.
- If “everything” is supposed to be plastic, why is there a call out to chassis and weapons? Does that mean only the chassis and weapon need to be of approved materials/plastics?
- Generally your robot should consist of either Commercial-Off-The-Shelf (COTS) parts, or an approved printed material.
- If it interacts directly with another robot, it should be PLA/ABS/PETG
- If it is custom fabricated (ie. not COTS) it should be PLA/ABS/PETG
- What kind of wheels and hubs are allowed?
- COTS parts are allowed such as Fingertech, Repeat Robotics, or Pololu hubs and wheels.
- Foam or rubber treads such as Lego tires are also allowed.
- Custom printed hubs should be PLA/ABS/PETG
- Traction additives such as silicone or latex are allowed
- “Wheels as Armor” Wheels of non-approved material should be kept to a minimum in size. Wheels that are large or bulky enough to act as armor on their own are not allowed (think BattleBots like "Copperhead" or "HUGE").
- While some events allow for custom cast silicone wheels, SCAR does not allow them at this time.
- Can I use metal or other heavy material inside of plastic to counterweight a weapon?
- No.
- Can I use metal bearings, axles, shafts, or other fasteners?
- Yes. Parts that are accessories to the function of the robot’s drive or weapon systems are fine as long as they don’t interact directly with an opponent or directly enhance the mass or effectiveness.
- Things like metal servo horns or gears are allowed for something like a lifter as long as the weapon is no longer effective if the plastic parts were removed.
- Can I use sheet metal for motor mounts?
- Standard COTS mount adapters are generally accepted as fine
- Generally brackets or mounts should not exceed motor diameter by more than 1.25x
- There are many other ways that a motor can be mounted with class-compliant materials. Try a printed clamp mount, zip ties, or face mount your motor directly into plastic. Trust us, it’ll be fine.
- Can anything which is approved as a metal part be made of or printed of an otherwise non-legal plastic, e.g. nylon screws, TPU wheel hubs or rubber washers?
- Non-metal “Commercial off the shelf” (COTS) fasteners are fine as long as they do not greatly enhance the effectiveness of the weapon or armor.
- Rubber or polyurethane for drive belts are allowed
- Rubber “wubs” to shock mount armor is not allowed
- Custom TPU wheel hubs are not allowed
- Is composite PLA/ABS/PETG or other printed materials like Nylon or TPU allowed?If you are unsure what to use, experienced builders in the class recommend:
- No! Composite materials such as carbon fiber or glass filled plastic are not allowed. Neither are anything other than PLA/ABS/PETG.
- There’s a weight class that allows these, it’s called full combat antweights.
- Blends of the approved materials that advertise additional compliant properties such as “flex PLA” are not allowed
- As long as the material is some form of PLA/ABS/PETG that can be printed on a stock Ender-3 it’s fine. (<260°C hotend)
- FusionFilaments HTPLA+
- Duramic PLA+
- Overture Super PLA+
- Hatchbox ABS
- Can I anneal or run my printed parts through post processing?
- As long as the post process is not adding any new materials, it is allowed.
- Annealing or smoothing with heat or acid is allowed
- Thin layers of decorative paint are allowed
- Epoxy coating, bondo, other common print filler style print smoothers not allowed
- Can I use tape?
- Conservative use of tape to hold lids on, or to cover removable power links is allowed
- Wrapping your robot in multiple layers of tape as armor is not allowed
- Any use of tape should be standard grade vinyl electrical tape, masking tape, or duct tape.
- Do I need to provide data sheets for the filament used at an event?
- No, we trust the community to not cheat the rules. Anything suspicious may permit additional investigation, but usually a quick visual inspection can verify if the material is not up to code.
- Using screws to combine plastic parts, what needs to be hidden? Does this not enhance the chassis or structure of the design?
- A reasonable amount of bolts to hold on weapons and armor are allowed
- As long as it’s obvious to the EOs that the hardware is not significantly enhancing the weapon or armor, it’s probably allowed.
- Non-approved material in weapons or armor should not interact directly with another robot