Carbon fiber oval tube is high‑performance, hollow profiles molded from T700/T800 carbon‑fiber prepreg with a 3K twill or UD black outer layer via autoclave, compression or pultrusion‑wrap processes. Their four straight walls combine circular‑tube torsional rigidity with flat‑side mounting advantages—ideal wherever aerodynamics, sleek lines, or tight spaces matter.
1. Materials & Manufacturing
Fiber System
Load‑bearing core: T700‑12K unidirectional tape laid 0°/90°
Appearance layer: 3K twill weave or UD black fiber for blemish‑free finish
Resin System
High‑temperature epoxy: Tg 180 °C (short‑term 200 °C)
Flame‑retardant epoxy: UL94‑V0 rail‑transit/battery compartment grade
Forming Processes
Pultrusion‑wrap: continuous lengths ≤ 3 m, straightness ≤ 0.3 mm/m
Compression molding: ± 0.05 mm accuracy, ideal for complex cavities
Autoclave curing: thick walls (3–5 mm) and mirror‑smooth surface
Post‑Processing
CNC‑machined slots, holes & M2–M8 tap
Pressed‑in 6061‑T6 aluminum or titanium inserts with 0.05 mm clearance
Surface finish: matte/gloss UV clear coat, laser‑etched scale, silkscreen logo
2. Key Benefits
Streamlined Geometry: Aspect ratio 1.2–3.0 reduces drag by 18 % at 30 m/s wind‑tunnel speeds
Exceptional Specific Strength: Density 1.55–1.60 g/cm³, tensile ≥ 2 800 MPa, just 45 % weight of equivalent‑stiffness aluminum
Non‑magnetic & X‑ray‑Transparent: No imaging artifacts for medical fixators and orthopedic pins
Fatigue Resistant: ≥ 90 % residual strength after 10⁶ load cycles
Custom Finishes: 3K twill glossy/matte, UD black, color decals, laser logo
3. Standard Stock Sizes
(2 mm wall, 1 000 mm length; up to 3 000 mm custom)
| Major × Minor (mm) | Inner (mm) | Weight (g/m) | EI (cm⁴) | Typical Use |
|---|---|---|---|---|
| 12 × 8 | 8 × 4 | 160 | 0.31 | Racing drone tail booms |
| 16 × 10 | 12 × 6 | 220 | 0.93 | FPV arms, gimbal extension rods |
| 20 × 12 | 16 × 8 | 290 | 2.10 | Slider rails, light booms |
| 24 × 14 | 20 × 10 | 360 | 4.20 | Robot joints, optical cross‑beams |
| 30 × 20 | 26 × 16 | 520 | 11.50 | Gripper arms, automotive paddles |
| 35 × 25 | 31 × 21 | 680 | 22.70 | Medical fixators, ski poles |
| 40 × 25 | 36 × 21 | 750 | 28.40 | Marine masts, airfoil supports |
| 50 × 30 | 46 × 26 | 1000 | 58.90 | Large‑scale UAV spars, camera jibs |
4. Joining & Assembly
Pressed‑in Oval Inserts: CNC‑machined profile, epoxy bond ≥ 2 kN pull‑out
Adhesive + Rivet: Epoxy structural glue & ø3 mm aluminum rivets for anti‑vibration
Dovetail Joint: 0.2 mm outer wall reduction for invisible extension
5. FAQ & Quality Checks
| Issue | Symptom | Cause | Factory Remedy | User Inspection |
|---|---|---|---|---|
| Out‑of‑tolerance ovality | Major/minor axis ± > 0.15 mm | Mold wear or fiber spring‑back | Re‑machine mold every 300 runs; pre‑compact fiber layers | Four‑point caliper measurement upon receipt |
| Surface fiber lift | Local frayed 3K weave | Inadequate demolding taper | Polish mold to Ra ≤ 0.4 μm; upgrade release agent | Visual/tactile; minor can be sanded |
| Corner whitening | Lamina whitening at tips | Resin pooling, uneven cure | Reinforce tips with UD fiber; control cure temperature ramp | Light‑through inspection for delamination |
| Insert loosening | Insert play, torque drop | Uneven adhesive layer | Sandblast + epoxy primer; maintain 0.05 mm clearance | Tap for solid bond before assembly |
| Shipping breakage | End‑cracks from impact | Inadequate end support | 6‑point foam support + wooden crate | Inspect for > 5 cm box dents on arrival |
6. Industry Examples
Medical: 9 × 6.5 mm fixator struts—artifact‑free X‑ray imaging
Aeroscale Models: 40 × 25 mm wing spars—62 % weight savings vs. basswood
Automotive: 30 × 20 mm paddle shafts—1 M cycle fatigue life, 3K glossy finish
Marine: 50 × 30 mm masts—1 000 h salt‑spray resistance
7. Ordering & Delivery
MOQ: 1 stock piece; 20 custom pieces
Lead Time: Stock in 48 h; custom in 7–10 days (incl. CNC)
Packaging: Film wrap → foam → reinforced carton; long tubes in crate
Documentation: Material certificate, RoHS/REACH, UL94‑V0 (if flame‑rated)
8. Technical Support
Free FEA Estimate: 24 h turn‑around on deflection & factor‑of‑safety
CAD Library: STEP/IGES with insert/CAD features
On‑site Training: “Bonding & Assembly” workshops for volume clients
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
In one line: These rectangular carbon fiber tubes bring strength, lightness, and elegance into a single profile—so your design carries creativity, not weight.
