Materials Learn about all the different materials you will encounter in FRC. Aluminum Aluminum is one of the most important materials in FRC. Different aluminum series have very different strengths, machining behavior, and real-world use in robot components. 6061-T6 Aluminum 6061-T6 is the most common structural extrusion material in FRC. Properties: High strength and stiffness Excellent machinability Holds tapped threads well Good balance of weight and durability Typical use: Structural extrusion (1x1, 2x1, 2x2) Drivetrain frames Tapped mounting points 5052 Aluminum 5052 is most commonly used as sheet metal stock in FRC. Properties: Very ductile (bends without cracking) Not ideal for tapped holes Good fatigue resistance in sheet form Easier to form than 6061 Typical use: Custom plates and gussets Sponsor-cut sheet parts Bent or formed panels 7000 Series Aluminum (e.g., 7075) 7000 series aluminum is a high-strength aerospace-grade material that is significantly stronger than 6061. Properties: Very high strength-to-weight ratio Stronger than 6061-T6 Lower corrosion resistance unless treated More expensive and more sensitive to machining conditions Typical use: High-performance custom components Lightweight but high-load structural parts Specialized drivetrain or mechanism elements 7000 Series in COTS FRC Components (WCP and Similar Vendors) In FRC, 7000 series aluminum (commonly 7075) is often used in COTS (Commercial Off-The-Shelf) components , especially from vendors like West Coast Products. Instead of teams machining it themselves, it is typically found in: High-strength drivetrain components Sprockets, hubs, and adapters Gearbox plates and structural side plates Shaft interfaces and high-load rotating assemblies Why vendors use it: Allows lighter parts without sacrificing strength Handles repeated high torque loads better than 6061 Improves durability in high-performance mechanisms Enables thinner, more compact designs while maintaining strength 6061 vs 5052 vs 7000 Series 5052 → flexible sheet metal, easy forming 6061 → standard structural extrusion, balanced performance 7000 series → high-performance COTS and custom components with maximum strength Key Idea Most FRC robots are built from 6061 extrusion and 5052 sheet, but 7000 series aluminum appears frequently in COTS components from vendors like West Coast Products because it enables stronger, lighter, and more compact high-performance parts. Steel Steel is a strong, heavy metal sometimes used in FRC for high-strength or wear-resistant applications. While aluminum is more common, steel is chosen when extra strength or durability is required. Why FRC Teams Use Steel Steel is used because it: Has very high strength Resists bending and deformation Handles high loads and impacts well Works well for shafts and fasteners Common Types of Steel in FRC Mild Steel Easy to machine and cut Used for simple brackets or mounts Heavier than aluminum Hardened Steel Very strong and wear-resistant Used for shafts, axles, and gears Difficult to machine without proper tools Common Applications Drive shafts and axles Bearings and wear surfaces High-load mounting hardware Gearboxes and transmission components Limitations Much heavier than aluminum Harder to machine and drill Can slow down robot performance if overused Requires stronger tools and more effort to modify Key Idea Steel is used in FRC when strength and durability matter more than weight. It is most commonly found in shafts, fasteners, and high-load components rather than full structural frames. Polycarbonate Polycarbonate (often called “polycarb”) is a tough, transparent plastic widely used in FRC for protective and structural sheet applications. Why FRC Teams Use Polycarbonate Polycarbonate is used because it: Is very impact resistant (won’t easily shatter) Is lightweight compared to metal Can be cut, drilled, and bent easily with heat Provides visibility through clear panels Common Applications Robot bumpers backing plates Protective guards over mechanisms Electrical covers and shields Intake guards and anti-interference panels Field-safe transparent barriers on mechanisms Properties to Know Flexible: can bend without cracking Durable: absorbs impacts without breaking Machinable: can be drilled and cut with proper tools Sensitive to heat: can melt or deform if overheated Important Handling Notes Use sharp drill bits to prevent cracking Avoid high drill speed and excessive pressure Support the material when drilling near edges Do not overtighten fasteners (can cause cracking over time) Key Idea Polycarbonate is a strong, impact-resistant plastic that is ideal for protective and lightweight structures in FRC. Proper drilling and fastening techniques are important to prevent cracking and extend part life. SRPP (Glass-Filled Polypropylene) SRPP is a glass-filled polypropylene sheet material commonly used in FRC, often supplied or popularized through vendors like West Coast Products. What It Is SRPP is a reinforced plastic made from: Polypropylene base material Glass fiber reinforcement This combination makes it significantly stronger and stiffer than standard plastic sheet. Why FRC Teams Use SRPP SRPP is used because it: Is lightweight compared to aluminum Has good stiffness for a plastic material Is impact resistant and durable Does not crack as easily as brittle plastics Is easy to cut and machine Common Applications Robot structural plates Mounting plates and brackets Intake side plates Lightweight gearbox or mechanism plates Non-metal structural components Manufacturing Notes Don't cut it with the CNC, use the laser cutter instead. Drills cleanly with proper speed and sharp bits if you heat up the edges with the flamethrower afterwards. Works well with bolts and rivets if you use large washers Limitations Not as strong as aluminum in high-load structural areas Can flex under heavy drivetrain loads Edge quality matters for strength (avoid rough cuts) Key Idea SRPP is a lightweight, glass-filled plastic sheet material used in FRC as a strong alternative to aluminum plates in lower-to-medium load applications, especially where weight savings matter. Plywood Plywood is a layered wood composite made by pressing thin sheets of wood veneer together with alternating grain directions. This structure gives it strength and resistance to cracking compared to solid wood. Why FRC Teams Use It Plywood is used because it: Is strong and relatively stiff for its weight Is easy to cut, drill, and shape with basic tools Holds fasteners reasonably well Is inexpensive and widely available Common Use in FRC Plywood is primarily used as bumper backing , where it: Provides a rigid structure for bumper assemblies Helps maintain bumper shape during impacts Supports mounting hardware that attaches bumpers to the robot frame Material Notes Typically 3/4" thick in FRC applications Grain layers are oriented for strength in multiple directions Works best when edges are sealed or protected Limitations Can crack or splinter if overloaded or poorly drilled Heavier than many modern composite materials Sensitive to moisture if left unsealed Key Idea Plywood is a strong, low-cost composite material used in FRC for structural support in bumper systems, where rigidity and durability are more important than weight savings. Common 3D Printer Filaments 3D printing filaments in FRC form a spectrum of materials that trade off between ease of printing, stiffness, toughness, and flexibility . Understanding how they relate helps teams choose the right material for each application instead of defaulting to one. The “Spectrum” of Filaments You can think of common filaments as a progression: PLA → PETG → ABS → Nylon → TPU As you move right: Parts become tougher and more impact-resistant Flexibility increases (until TPU) Printing difficulty generally increases Heat and fatigue resistance improve Rigid vs. Tough vs. Flexible PLA (Rigid, easy, brittle) Most rigid but least durable Breaks suddenly under impact Best for prototypes and fit checks ➡️ Baseline material PETG (Tough, slightly flexible) Similar stiffness to PLA but much tougher Absorbs impacts instead of cracking Good “default functional” material ➡️ Step up in durability from PLA ABS (Tough + heat resistant) Similar toughness to PETG but better heat resistance More stable in warmer environments Warps more easily when printing ➡️ Functional + environment-resistant upgrade Nylon (Very tough, wear-resistant, flexible) Much more impact resistant than ABS/PETG Excellent fatigue resistance (bending repeatedly) Lower stiffness than PLA/ABS but far more durable ➡️ Best for moving/wear parts TPU (Flexible, elastic) Completely different behavior from others Bends, compresses, and returns to shape Absorbs impact instead of resisting it ➡️ Used when flexibility is the goal How They Compare in Use PLA: “Does it fit?” prototypes PETG/ABS: Real robot parts with moderate load Nylon: High-stress or moving parts TPU: Contact, grip, or shock absorption Key Relationship Idea These filaments are not separate choices—they form a progression from rigid and easy (PLA) to tough (Nylon) to flexible (TPU) . Most FRC teams use a mix depending on whether the part needs accuracy, strength, wear resistance, or compliance. When to use which material Each material used in FRC has distinct mechanical and manufacturing properties that determine how it behaves under load, during machining, and in real-world robot use. 6061-T6 Aluminum High strength and stiffness Excellent machinability Holds tapped threads well Maintains shape under load with minimal flex Can be anodized for corrosion resistance 5052 Aluminum High ductility (bends without cracking easily) Lower strength than 6061-T6 in rigid structures Very good fatigue resistance in sheet form Poor thread-holding capability compared to 6061 Excellent for forming and sheet fabrication Polycarbonate Extremely high impact resistance (does not shatter) Flexible and can bend significantly before failure Transparent, allowing visibility through panels Sensitive to heat during machining Crack-resistant compared to brittle plastics like acrylic SRPP (Glass-Filled Polypropylene) Lightweight with moderate stiffness High vibration damping compared to metals More rigid than standard plastics due to glass fill Low density relative to aluminum Good fatigue resistance in sheet applications Steel Very high strength and hardness Excellent wear resistance High density (heavy compared to aluminum) Maintains shape under extreme loads Can be heat-treated for increased hardness Plywood Cross-laminated structure resists splitting Good stiffness for its weight Anisotropic (strength depends on grain direction) Absorbs impact energy without immediate fracture Sensitive to moisture and environmental conditions Key Idea Each material behaves differently under stress, machining, and impact. Understanding these unique properties allows FRC teams to choose the right material for strength, weight, flexibility, and durability requirements. Sheet Thickness Sheet materials in FRC come in standard thickness increments. These increments strongly affect stiffness, weight, and how parts behave under load. Common Sheet Thickness Increments Most sheet materials (aluminum, polycarbonate, plastics) are typically available in: 1/16" 1/8" 3/16" 1/4" 3/8" 1/2" These standard sizes are what most FRC designs are based on. How Thickness Affects Strength 1/16" Very lightweight Low stiffness Easily flexes under load Best for non-structural covers or light panels 1/8" Common general-purpose thickness Good balance of stiffness and weight Widely used for gussets and light structural plates 3/16" Noticeably stiffer than 1/8" Much better resistance to bending and vibration Used when higher structural rigidity is needed 1/4" High stiffness and strength Strong resistance to bending and impact Significant weight increase Used for structural or high-load plates 3/8" Very rigid Used in specialized high-load or mounting applications Often heavier than necessary for most robot mechanisms 1/2" Extremely stiff and strong Minimal flex even under heavy loads Very heavy for robotics use Typically reserved for specialty or extreme-load components Why Teams Pocket Parts Reduces weight without fully reducing stiffness where it matters Maintains strength along outer load paths while removing unnecessary material Improves robot performance by lowering overall mass Allows designs to stay structurally efficient instead of uniformly overbuilt Key Idea FRC sheet design is about balancing standard thickness options with strategic material removal. Pocketing helps teams keep strength where needed while eliminating excess weight.