Materials

FRC robots are made out of a lot of different materials, we are going to walk through some of the major categories so that teams can make the right choices based on weight, strength and cost requirements they have.

Acrylic (lucite or PMMA)

  • Acrylic is a see through polymer that is rather lightweight
  • Acrylic prone to cracking and should only be used in instances where you expect to have low shear loads
    • Acrylic is very sensitive to point loading and cracks easily
  • Acrylic is not a homogeneous material
    • This means it has different structural properties depending on the direction and type of loading
    • Acrylic’s strength will change depending on how long it has been loaded and in what temperature
    • Acrylic’s strength is also reduces when it is exposed to sunlight and especially organic solvents
  • Acrylic is cheap
  • Acrylic can come in sheets, bars, rods and tubes
  • Acrylic can be cut with hand tools, wood working machines, metal working machines, and lasers
  • Acrylic can be welded chemically
  • Acrylic can be easy bent and molded into a variety of shapes in most FRC shops
  • Acrylic is not a conductor

Aluminum

  • Aluminum is a light weight metal that comes in a variety if of alloys and heats treats
  • Aluminum, like most metals is considered a homogeneous material
    • Aluminum’s strength will change as temperatures increase, but FRC teams will never see those temperatures
  • Aluminum is moderately expensive
  • Aluminum can come in sheets, bars, rods and tubes
  • Aluminum can be cut with hand tools, metal working machines, water jets, lasers and plasma cutters
  • Aluminum can be welded by using heat or friction
  • Aluminum can not be easy bent and molded by most FRC shops
  • Aluminum is a conductor

Carbon Fiber

  • Carbon Fiber is a combination of a fabric and hardener commonly called carbon composite
    • Carbon composites can be made out uni directional fabric, woven fabric, chopped fabric or tape
  • Carbon Fiber is light and can be used when you need high strength and low weight
  • Carbon Fiber is not a homogeneous material
    • This means it has different structural properties depending on the direction and type of loading
    • Carbon composite parts are very sensitive to the configuration of the part, particularly the ;
      • Ply direction
      • Ply stack
      • % and location of wrinkles
  • Carbon Fiber is very expensive
  • Carbon Fiber can come in sheets, bars, rods and tubes
  • Carbon Fiber can be cut with hand tools, carbon composite working machines and metal working machines
    • Carbon fiber dust is harmful if breathed in
    • Carbon fiber dust is harmful if it comes in contact with your eyes
  • Carbon Fiber can not be welded
  • Carbon Fiber can be formed in a variety of shapes
    • Carbon Fiber shape can not be changed after it is cured
  • Carbon Fiber is not a conductor

Delrin (POM)

  • Delrin is an opaque polymer that is rather lightweight
  • Delrin is rather dense and can be used in variety instances where you have high loads or high friction
  • Delrin is not a homogeneous material
    • This means it has different structural properties depending on the direction and type of loading
  • Delrin is moderately expensive
  • Delrin can come in sheets, bars, rods and tubes
  • Delrin can be cut with hand tools, wood working machines, metal working machines and lasers
  • Delrin can be welded chemically
  • Delrin can be easy bent and molded into a variety of shapes in most FRC shops
  • Delrin is not a conductor

Fiber Glass

  • Fiber glass is a combination of a fabric and hardener commonly called fiber glass composite
    • Fiber glass composites can be made out uni directional fabric, woven fabric, chopped fabric or tape
  • Fiber glass is light and can be used when you need high strength and low weight
  • Fiber glass is not a homogeneous material
    • This means it has different structural properties depending on the direction and type of loading
    • Fiber glass composite parts are very sensitive to the configuration of the part, particularly the ;
      • Ply direction
      • Ply stack
      • % and location of wrinkles
  • Fiber glass is moderatly expensive
  • Fiber glass can come in sheets, bars, rods and tubes
  • Fiber glass can be cut with hand tools, carbon composite working machines and metal working machines
    • Fiber glass dust is harmful if breathed in
    • Fiber glass dust is harmful if it comes in contact with your eyes
  • Fiber glass can not be welded
  • Fiber glass can be formed in a variety of shapes
    • Fiber glass shape can not be changed after it is cured
  • Fiber glass is not a conductor

Poly carbonate (lexan)

  • Poly carbonate is a see through polymer that is rather lightweight
  • Poly carbonate is impact resistant
  • Poly carbonate is not a homogeneous material
    • This means it has different structural properties depending on the direction and type of loading
  • Poly carbonate is moderately expensive
  • Poly carbonate can come in sheets, bars, rods and tubes
  • Poly carbonate can be cut with hand tools, wood working machines, metal working machines water jets
    • Poly carbonate can be cut using a laser, but it gives off chlorine and needs to be properly vented
  • Poly carbonate can be welded chemically
  • Poly carbonate can be easy bent and molded into a variety of shapes in most FRC shops
  • Poly carbonate is not a conductor

Steel

  • Steel is a heavy metal that comes in a variety if of alloys and heats treats
  • Steel, like most metals is considered a homogeneous material
    • Steel’s strength will change as temperatures increase, but FRC teams will never see those temperatures
  • Steel is moderately cheap
  • Steel can come in sheets, bars, rods, tubes and cables
    • Nearly all dead axles in FRC should be steel
    • Nearly all fasteners in FRC should be steel
  • Steel can be cut with hand tools, metal working machines, water jets, lasers and plasma cutters
  • Steel can be welded by using heat
  • Steel can not be easy bent and molded by most FRC shops
  • Steel is a conductor

Teflon (PTFE)

  • Teflon is an opaque polymer that is rather lightweight and has a very low coefficient of friction
  • Teflon is impact resistant
  • Teflon is not a homogeneous material
    • This means it has different structural properties depending on the direction and type of loading
  • Teflon is moderately expensive
  • Teflon can come in sheets, bars, rods and tubes
  • Teflon can be cut with hand tools, wood working machines, metal working machines water jets
    • Teflon needs to be properly secured when machining
  • Teflon can be welded chemically
  • Teflon can be easy bent and molded into a variety of shapes in most FRC shops
  • Teflon is not a conductor

Wood

  • Wood is an opaque fibrous material that is rather lightweight
    • The type of wood can change the mechanical properties significantly
      • We recommend pine
  • Wood is rather dense and can be used in variety instances where you have high loads or high friction
  • Wood prone to cracking and should only be used in instances where you expect to have low shear loads
    • Wood is very sensitive to point loading and cracks easily
  • Wood is not a homogeneous material
    • This means it has different structural properties depending on the direction and type of loading
    • Wood is very sensitive to the loading as it relates to grain direction
  • Wood is cheap
  • Wood can come in sheets, bars
  • Wood can be cut with hand tools, wood working machines, metal working machines and lasers
  • Wood can not be easy bent and molded by most FRC shops
  • Wood is not a conductor

 

Additional resources for material selection

 

 

 

 

Leave a Reply

Your email address will not be published. Required fields are marked *

*