Building Materials

Below is a list of common materials used in robot construction:

Metal – Aluminum bars or plates (lightweight and pliable)

Metal – Steel bars or plates (strong but less common due to high weight)

Metal – Titanium bars or plates (usually used for wedge construction or single armor plates on a larger bot)

Plastic – UHMW (ultra high molecular weight polyethylene) (tough plastic similar to a kitchen cutting board)

Plastic – Lexan sheets (plastic, also used for the arena walls)

Plastic – 3D printed materials (PLA, PLA+, ABS, PETG, Nylon, etc. – see the 3D printing section below for more details)

Are these the only materials I can use? Absolutely not. The only restrictions on construction materials are the event rules and your imagination! Builders have used things from cardboard to wood to copper. Even duct tape! Be creative in your design but always think about the benefits versus drawbacks of the material you are using.

How to choose materials? Every bot typically uses a combination of materials for armor and internal parts depending on your design and placement. (Protecting the wheels, top/bottom plates for the internal electronics and motors, etc.)

As with most materials, each have their own benefits and drawbacks. Some are heavier but stronger, some are more flexible but can tear or bend. Some are light and strong, but are expensive. Choose your materials based on your design and budget, test it, and make changes as needed.

Quick Tip: Iterative design is a design methodology based on a cyclic process of prototyping, testing, analyzing, and refining a product or process. Based on the results of testing the most recent iteration of a design, changes and refinements are made.

3D Printing

3D printing has become extremely popular in recent years. Before you get into 3D printing a bot, make sure understand how it works and the limitations of the materials themselves (filament type). Choosing the wrong filament can mean the difference between a tough bot and one that shatters like glass on impact!

Simplify 3D maintains a fantastic “Ultimate 3D Printing Materials Guide” to help you better understand the qualities and drawbacks of most commercially available 3D filament materials on the market today. Below is a summary to get your started:

  • ABS – ABS is a low-cost material, great for printing tough and durable parts that can withstand high temperatures.
  • TPU – Flexible filaments, commonly referred to as TPE or TPU, are known for their elasticity allowing the material to easily stretch and bend.
  • PLA – PLA is the go-to material for most users due to its ease-of-use, dimensional accuracy, and low cost.
  • PLA Plus (+) – This is a newer version of PLA that combines the ease-of-use quality of regular PLA with the durability qualities of ABS.
  • HIPS – HIPS is a lightweight material most commonly used as a dissolvable support structure for ABS models.
  • PETG – PET and PETG filaments are known for their ease of printability, smooth surface finish, and water resistance.
  • Nylon – Nylon is a tough and semi-flexible material that offers high impact and abrasion resistance. It is an ideal choice for printing durable parts.
  • ASA – ASA is a common alternative to ABS and is great for outdoor applications due to its high UV, temperature, and impact resistance.
  • Polycarbonate – Polycarbonate is known for its strength and durability. It has very high heat and impact resistance making it an ideal choice for tough environments.
  • Polypropylene – Polypropylene is great for high-cycle, low strength applications due to its fatigue resistance, semi-flexible, and lightweight characteristics.
  • PVA – PVA is commonly known for its ability to be dissolved in water and is often used as a support material for complex prints.
  • Metal Filled – Metal filled filaments are made by mixing a fine metal powder into a base material, providing a unique metallic finish and added weight.
  • Wood Filled – Wood filaments combine a PLA base material with cork, wood dust, or other derivatives, giving the models a real wooden look and feel.
  • Carbon Fiber Filled – Carbon fiber filaments contain short fibers that are infused into a PLA or ABS base material to help increase strength and stiffness.

Metal Working

A member of our NC team using an angle grinder wheel to cut steel and titanium plates for bot armor. So many sparks!

Using various types of metal for bot construction is a classic and popular way to add strength and durability. This is especially true for bots in the higher weight classes; such as 30 lbs or above. Before you begin purchasing materials, below are some things to consider:

Types of Metal

  • Aluminum – Low cost. Light weight. Easy to cut and shape. Very hard to weld. Best suited for inner frames or bot locations that will take minimal damage or stress.
  • Steel – Low/Medium cost. Heavy weight. Hard to cut and shape. Easier to weld. Best suited for armor and weapons.
  • Titanium – Higher cost. Light weight. Hard to cut and shape. Harder to weld. Can be used for either inner frames or armor and weapons.

Tools to work with metal

KEY SAFETY LESSON! Always use extreme caution when using any tool to cut, drill, or weld. Follow the manufacturer’s instructions and use all recommended safety equipment. This is especially true when it comes to working with metal. Trust me, you don’t want to get steel dust particles in your eyes or mouth!

Cutting, Drilling, and Grinding Metals: In general, the tool you use will need to have equal or greater hardness when compared to the metal you are attempting to cut. For example, you would not want to use a saw motor or blade designed for cutting wood on steel or other types of metals.

How do I know if my tool can cut the metal I’m working on? The easiest way to tell if your saw or drill should be used to cut the metal you are working with is to look at the label. Almost all tools, drill bits, and blades used for cutting metal will specifically say so in their description.

Example of saw blades used for cutting wood and plastic. There are typically less teeth on the blade.

Example of saw blade used for cutting soft to harder metals. There are typically many more teeth or the teeth are replaced with a solid coating of a hardened abrasive; such as cobalt or diamond tipped.