I. Product Definition
The square carbon fiber tube is a hollow structural profile with a square/rectangular cross-section, fabricated by pultrusion or compression molding. It employs continuous carbon fiber (T300/T700 grade) as reinforcement and epoxy resin as the matrix. Compared to round tubes, it offers 40% higher torsional rigidity, planar mounting stability, and sub-millimeter dimensional accuracy – making it ideal for modular systems like robotic arms, drone frames, and optical platforms.
II. Materials & Manufacturing
Fiber Systems
- Standard: T300 12K unidirectional + 3K twill outer layer (visible carbon weave)
- High-Strength: T700 12K full unidirectional, 18% higher modulus
- High-Modulus: M40J 6K hybrid layup for precision optical beams
Resin Systems
- Standard epoxy: Operating temp. -40℃ to 120℃
- High-temp epoxy: T<sub>g</sub> 180℃, short-term resistance to 200℃
- Flame-retardant epoxy: UL94-V0 for UAV battery trays/rail transit
Processes
- High-temp pultrusion: Seamless 3–6m lengths, straightness ≤0.2mm/m
- Vacuum compression molding: Dimensional tolerance ±0.05mm
- Secondary CNC machining: Milling slots, drilling, threading, aluminum inserts
Surface Finishes
- 3K twill + matte/gloss UV coating
- Matte black PU paint (non-reflective for optics)
- Anodized inner walls for adhesive bonding
III. Mechanical Properties
(30×30×2mm specimen; ASTM standards)
| Property | Value | Test Method |
|---|---|---|
| Density | 1.60 g/cm³ | ASTM D792 |
| Flexural Strength | 650 MPa | ASTM D790 |
| Flexural Modulus | 68 GPa | ASTM D790 |
| Interlaminar Shear | 75 MPa | ASTM D2344 |
| Torsional Stiffness | 3.2 N·m/° | In-house Standard |
| CTE | 1.2×10⁻⁶ /℃ | TMA |
IV. Standard Sizes
(Wall thickness: 2.0mm; Custom lengths up to 3000mm)
| Dimensions (A×B mm) | Weight (g/m) | Flexural Stiffness EI (N·mm²) | Applications |
|---|---|---|---|
| 15×15 | 145 | 2.1×10⁶ | Mini UAV arms, FPV frames |
| 30×30 | 320 | 1.9×10⁷ | Laser mounts, optical beams |
| 50×50 | 780 | 1.1×10⁸ | 3D printer gantries |
| Rectangular sections (e.g., 20×40mm) available. Corner thickening (R-angle reinforcement) for enhanced rigidity. |
V. Joining Solutions
- Internal aluminum sleeves: For M4/M6 threads (torque ≥8 N·m)
- Carbon corner brackets: 90°/135° angle plates with M5 bolts
- Adhesive + riveting: Epoxy + stainless steel rivets for vibration resistance
- Tenon jointing: End-to-end connection with 0.2mm tolerance
VI. Customization
Surface Textures
- 3K gloss twill (aesthetic)
- 3K matte twill (anti-glare)
- UD black veil (strength-optimized)
Machining Options
- CNC milling: T-slots, V-grooves, dowel holes
- Laser engraving: Logos/scale markings
- Chamfered edges (0.5×45°)
VII. Quality Assurance
- Certifications: ISO 9001, AS9100D
- Testing: 3-point bending/torsion/shear tests (1 sample per 50m)
- NDT: 100% ultrasonic A-scan for delamination/voids
- Compliance: RoHS/REACH certificates included
VIII. Case Studies
- 3D scanner beam (30×30×2mm): Replaced 3kg aluminum beam, reducing vibration by 60% with 288g weight.
- FPV drone frame (20×20×2mm): 120g weight savings, extending flight time 8%.
- Camera gantry (50×50×3mm): Maintained 0.3mm straightness over 2.5m at 2m/s speed.
IX. Order Process
- Submit dimensions (A×B×thickness×length) and load/temperature requirements.
- Receive FEA report and quote within 24 hours.
- Approve machined samples in 2–3 days.
- Bulk delivery in 7–10 days (≤3m seamless lengths).
X. Packaging & Shipping
- Foam-wrapped tubes in reinforced cartons (≤20kg/box).
- Air transport: Aluminum corner guards + plywood crates for ≥2m lengths.
Offline Contracts
All sales of our carbon fiber materials are conducted through offline contract agreements to ensure each order precisely meets your specifications, compliance requirements, and agreed payment terms. Please contact our sales team to initiate the contract process and discuss project details.
| name | value | unitCode | unitText |
|---|---|---|---|
| MOQ | 50 | PCS | |
| Lead Time | 5–20 | business days | |
| Material | Carbon Fiber | ||
| Size | Customizable (inner diameter / outer diameter / length) |
Resources
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