+86 15303735673
Jessica@frpzs.com
Technical Data
Advanced Tooling for Industrial Composite Piping
In the 2026 industrial landscape, large-diameter FRP tubes are critical for municipal water systems, chemical transport, and structural supports. The φ186*6mm FRP Round Tube Pultrusion Mould is a high-precision engineering tool designed to handle the massive internal pressures and thermal profiles associated with large-scale pultrusion. At Henan Zhongsheng (FRPZS), we focus on the synergy between the outer die and the internal mandrel to ensure perfect wall thickness uniformity and a mirror-smooth finish for high-flow efficiency.
1. Technical Mechanics of the Round Tube Mould
Manufacturing a 186mm diameter tube with a 6mm wall thickness requires more than just a hollow die. It involves precise control over the internal and external surfaces simultaneously:
- Internal Mandrel Support: The φ174mm internal mandrel must be perfectly centered within the φ186mm cavity. Our molds utilize a reinforced bridge design to prevent mandrel deflection under high pulling forces.
- Thermal Gradient Control: For a 6mm wall thickness, the exothermic heat peak must be managed. We implement four-zone heating to ensure the resin cures uniformly from the inside out, preventing internal micro-cracks.
- Compaction Ratio: The entrance of the mold is engineered with a 1-2 degree taper to gradually compress the impregnated fibers, forcing out air bubbles and ensuring a high-density structural matrix.
2. Premium Materials & Execution Standards
Large-diameter pultrusion places extreme stress on the mold steel. We offer several high-performance alloys to match your production volume:
- Cr12 / Cr12MoV: The standard for high-volume glass fiber production, offering exceptional hardness (HRC 58-62) after vacuum quenching.
- H13 (4Cr5MoSiV1): Ideal for high-temperature resins like Phenolics or Epoxies, providing superior resistance to thermal fatigue.
- Surface Finish (Mirror Polishing): The internal cavity is polished to Ra 0.012, significantly reducing friction and ensuring the "Class A" surface required for chemical resistance.
3. φ186*6mm Mould Technical Parameters
| Parameter Specification | Standard Value | Performance Impact |
|---|---|---|
| Mold Bore Diameter | φ186.0 mm | Ensures outer diameter precision. |
| Mandrel Diameter | φ174.0 mm | Determines the 6mm wall thickness. |
| Concentricity | ≤ 0.05 mm | Ensures wall thickness uniformity. |
| Straightness | 0.02 mm / 1000 mm | Prevents bowing in long pipe sections. |
| Cavity Hardness | HRC 55 - 60 | Resists glass fiber abrasion. |
| Plating Thickness | 0.04 - 0.05 mm | Hard chrome layer for low friction. |
4. Optimized Performance Factors
- Resin Selection: Whether using Vinyl Ester for chemical plants or Polyurethane for structural strength, our molds are compatible with all major 2026 resin systems.
- Fiber Orientation: The mold design accommodates a mix of longitudinal rovings and continuous filament mats (CFM) to provide both tensile and hoop strength.
- Pulling Speed: Our high-smoothness cavities allow for 15-20% faster pulling speeds compared to standard industrial molds, maximizing your ROI.
10 Professional FAQs: Large-Diameter FRP Tube Tooling
Q1: "How do you ensure the 6mm wall thickness is consistent around the entire 186mm diameter?"
A: We use high-precision centering guides and a reinforced mandrel support system that minimizes "mandrel sag" during the pultrusion process.
Q2: "What is the expected life of the chrome plating for a φ186mm mold?"
A: With proper maintenance and non-abrasive resins, you can expect 60,000 to 80,000 meters of production before needing to re-plate.
Q3: "Can this mold handle Carbon Fiber pultrusion?"
A: Yes, but for carbon fiber, we recommend H13 steel with a specialized nitriding or DLC coating to handle the specific fiber properties.
Q4: "Is the mold heated by electricity or oil?"
A: This mold is compatible with both. We provide standard mounting holes for electric heating rods or internal channels for thermal oil circulation.
Q5: "Why is the straightness tolerance so tight (0.02mm)?"
A: In industrial piping, even a slight curve makes connecting long sections nearly impossible. Straightness is the key to leak-free jointing.
Q6: "How do you prevent the mandrel from sticking inside the cured tube?"
A: The mandrel features a precision "release taper" and is polished to a mirror finish. This, combined with high-quality internal release agents, ensures smooth extraction.
Q7: "Can I use this mold for both Polyester and Vinyl Ester resins?"
A: Yes. The hard chrome surface is chemically inert and highly resistant to the styrene in polyester and the aggressive chemistry of vinyl esters.
Q8: "What is the typical length of a φ186mm tube mold?"
A: For a tube of this size, we typically design the mold length between 900mm and 1200mm to ensure full curing at high pulling speeds.
Q9: "Do you provide a technical drawing for approval before manufacturing?"
A: Every custom mold project includes a comprehensive 3D CAD design review and a 2D engineering drawing for your final signature.
Q10: "How do we clean the mold after a production run?"
A: The mold should be cleaned while warm using a brass scraper and a suitable solvent, followed by a coating of protective rust-inhibitor oil.
Expert Large-Diameter Tooling Solutions
Scale up your composite production with Henan Zhongsheng Composite Materials Co., Ltd. Led by Jessica Huang, our engineering team specializes in the design and fabrication of world-class FRP Round Tube Pultrusion Moulds.
Optimize your production line today:
- Lead Engineering Consultant: Jessica Huang
- Technical RFQ Email: Jessica@frpzs.com
- Global WhatsApp: +86 15303735673
