Plastic Antweight (Class)

Overview

The Plastic Antweight (also known as PlAnt) Weight Class of robots is a 1lb (1 pound/453 gram) combat robot class, with notable limitations compared to the standard Antweight. These largely include material and manufacturing constraints, with most PlAnt competitions allowing a limited list of 3D printed plastics to be used for a majority of the robot construction.

Aggie Combat Robotics has been participating in PlAnt competitions since April 2026, and it is the longest running class in the organization. Notable examples of ACR robots in this class include Chill Guy, Cortisol Spike, and Drain Gang.

Material Choice

PLA

Simple PLA is a bad choice for Plastic combat, due to its brittle nature, and pore impact resistance. While some specific mixes and proprietary versions of PLA perform very well, standard PLA is a poor choice for PlAnt combat robots.

PLA Pro

PLA Pro exhibits better behaviors more suitable for combat competition, namely a higher impact resistance and better layer adhesion. It is still unadvised to use this material for a PlAnt robot if something like Bambu PLA Tough+ is available.

Bambu PLA Tough+

A very specific mix of PLA made by Bambu, exhibits exceptional properties and performance under both impact and bending loads. Highly advisable to use this material for manufacturing of PlAnt parts, as it is far more likely to survive in the environment of PlAnt combat.

ABS

ABS is good, performs kind of like PLA Tough, but is much harder to print and warps. Is more temperature resistant than PLA

PETG

NEVER USE PETG FOR COMBAT ROBOTS^[2]. PETG is very brittle under high shock load, and will simply break instead of deforming.

ASA

Performs very much like PLA Pro but is lighter. Can be useful in parts where weight savings are necessary, but is very hard to print, as it requires a heated chamber of relatively high temperature.

Fasteners

Aggie Combat Robotics uses metric fastener sizes for PlAnt robots. These are denoted as m[n] where n is the thread pitch diameter. For PlAnts, m2 and m3 fasteners are the most common, as they fit the scale of the robots well, with the occasional m4 fastener being necessary.

Heatset Inserts

As shown by the robots from the first ever development cycle as ACR, please do not use these as they will get ripped out of their respective part when the robot is hit hard enough.

Plastite screws

All fasteners should be these, if they go directly into plastic. These are meant to bite into plastic, and hold much more solid than heatset inserts. DO NOT FORGET loctite, or most fasteners will vibrate loose over the course of a match.

Design Considerations

When designing a PlAnt combat robot, there are many important factors to consider and keep in mind. The robot must comply with the rules presented by the event it is attending, which may include both safety and other specific construction rules. Keeping weight in mind by assigning materials to CAD parts is also important, as being even a gram over budget will disqualify your robot from competing at most, if not all, events.

Safety Regulations and Event Specifics

The robot must have a switch which can be externally actuated, which when disabled brings the robot to a complete stop, even if it is in the middle of being controlled. A physical restraining device must also be applied to the weapon due to safety concerns, in order to prevent potential injury. Some event explicitly ban robots which do not have an active weapon. This means that bots that simply rely on control, such as pure wedges, are not allowed at these events, in order to make for more exciting competition.

Drivetrain Design

The two main drive systems available to a PlAnt builder are 2 wheel and 4 wheel tank drive. A 2 wheel drive setup will typically be directly driven by the output shafts of the motors slotting into the wheels hubs, while 4 wheel drive will connect these to a second set of wheels with some sort of belt or gear system. Robots come in a wide variety of shapes and sizes, and it is entirely up to the builder what shape they choose for their design. Wider designs will have better steering authority, while longer designs will be more stable at speed, and when hitting other robots. Wheels may be made from foam or cast from polyurethane, with the latter yielding better performance in the box. The frictional losses of the drive are an extremely important consideration, as small amounts of friction can completely ruin drivetrain performance at these scales. Aim for 35-60mm wheels, and general dimensions of between 180x180 to 240x240mm for your drivetrain.

Weapon Design

Weapons can be active or passive. Examples of a passive weapon include a wedge, forks, or a lifter design. Examples of active weapons include hammers, and horizontal and vertical spinners. When designing a wedge or forks, make sure that the angle from the ground is not too steep to allow an opponent to slide onto them. Consider including barbs on forks and wedges to allow an opponent to get stuck on them for better control. Vertical spinners come in a variety of shapes and sizes, with the main categories being drums, eggbeaters, bars, and disks. These are discussed further in the Active Weapons article. Do not use eggbeaters in PlAnt combat, as they will simply snap due to the thin nature of their design.

Electronics

This section has not yet been written