Rectangular Carbon Fiber Tubes are manufactured from T700/T800‐grade carbon fiber prepreg via compression molding or autoclave curing into a one‐piece hollow profile. Their straight walls deliver inherent torsional resistance, while your choice of 3K twill or UD black surface ensures a fusion of lightweight, rigidity, and aesthetics—making them the ideal aluminum replacement for “square tubes.”
1. Materials & Manufacturing
Fiber System
Load‑bearing layer: T700‑12K unidirectional tape oriented 0°/90°
Surface layer: 3K twill weave for clear pattern–no broken filaments
Resin System
High‑temperature epoxy: Tg 180 °C (short‑term 200 °C)
Flame‑retardant epoxy: UL94‑V0 grade for rail transit/battery compartment use
Forming Processes
Compression molding: ± 0.05 mm dimensional accuracy for batch runs
Autoclave curing: optimal corner compaction and mechanical performance
Post‑processing
CNC milled slots, drilled holes, tapped M2–M8 on end faces
Optional pressed‑in aluminum (6061‑T6) or titanium threaded inserts
Surface finishes: matte/glossy UV clear coat, laser‑etched scales, silkscreen logo
2. Mechanical Properties (40×20×2 mm sample)
| Property | Typical Value | Test Standard |
|---|---|---|
| Density | 1.6 g/cm³ | ASTM D792 |
| Longitudinal Tensile Strength | 2 800 MPa | ASTM D3039 |
| Longitudinal Modulus | 160 GPa | ASTM D3039 |
| Interlaminar Shear Strength | 80 MPa | ASTM D2344 |
| Axial CTE | < 1.0×10⁻⁶ /°C | TMA |
| Service Temperature | −50 °C to +180 °C | Long‑term |
3. Standard Stock Sizes (2 mm wall, 1 000 mm length; up to 3 000 mm custom)
| WxH (mm) | Inner (mm) | Weight (g/m) | Ix (cm⁴) | Example Use |
|---|---|---|---|---|
| 20×10 | 16×6 | 190 | 0.42 | Gimbal rails |
| 25×15 | 21×11 | 260 | 1.10 | Light stands, robot links |
| 30×20 | 26×16 | 340 | 2.56 | Optical beams, printer carriages |
| 35×25 | 31×21 | 420 | 4.70 | End‑effectors, claw arms |
| 40×20 | 36×16 | 400 | 5.12 | UAV fuselage spars |
| 50×25 | 46×21 | 520 | 10.3 | Industrial camera gantries |
| 60×30 | 56×26 | 720 | 20.5 | High‑speed handling stages |
| 80×40 | 76×36 | 1080 | 58.7 | Large 3D printer frames |
4. Joining & Assembly
Pressed‑in Aluminum Inserts: Machined stepped corners, 6061‑T6 alloy, M4–M8 threads, ≥ 15 N·m torque
Angle‑Bracket System: 90°/135° carbon corner plates + M5 bolts, 500 cycles without thread slip
Adhesive + Rivet: Epoxy structural glue + stainless‑steel hollow rivets for vibration resistance
Dovetail Fit: One end reduced by 0.15 mm for invisible, self‑locking extension
5. FAQs & Solutions
| Issue | Symptom | Cause | Factory Remedy | User QC |
|---|---|---|---|---|
| Corner Cracks | Cracks at four corners | Prepreg not compacted; resin pooling | Pre‑compaction + temperature control; R0.5 corner radii | Inspect 45° corner under light |
| Surface Wrinkles | Wavy twill appearance | Overlapping vacuum bag/bleeder cloth | Smooth after layup; use 3D bleeder cloth | Visual/tactile; minor fixable |
| Pinholes | White spots | Moist prepreg or trapped air | Pre‑bake 80 °C for 2 h; vacuum pre‑compaction | Light‑transmission check; reject > 1 mm |
| Dimensional Variance | ± 0.2 mm | Mold wear or uneven resin shrinkage | Mold re‑machining every 500 runs; resin formula tweak | Caliper check on delivery |
| Thread Slip | Loose inserts | Insufficient bonding | Sandblast + epoxy primer; add knurling | Torque test pre‑assembly |
6. Industry Applications
Aerospace: Satellite solar‑wing supports, UAV wing box spars
Medical: CT scanner rails, surgical‑robotic arm links
Automation: High‑speed pick‑and‑place gantries, laser‑cutting beams
Imaging: Camera jibs, slider arms, cantilever light booms
Transport: Battery‑pack frames, fuel‑cell forklift forks
7. Ordering & Delivery
MOQ: 1 piece stock; 20 pieces for custom
Lead Time: Stock in 48 h; custom 7–10 days (incl. machining)
Packaging: Film wrap → foam → double‑wall carton; ≥ 2 m in reinforced crate
Certifications: Includes material certificates, RoHS, REACH, UL94‑V0 (if requested)
8. Technical Support
Free FEA Estimate: Provide load/constraint; get deflection & safety factor in 24 h
CAD Library: STEP/IGES files with hole, chamfer, insert dimensions
On‑site Training: “Bonding & Assembly” workshops for volume customers
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
With “half the weight, ten times the strength,” these rectangular carbon fiber tubes shift the weight burden to your design, not your frame—delivering performance where it counts.
