φ38*3mm FRP Round Tube Pultrusion Die
This FRP pultrusion mould is used to produce composite profiles such as rods, round tubes, beams, and frames. Mounted on the pultrusion machine, it shapes the finished FRP profile as resin-impregnated roving is drawn continuously through the die cavity.
Executive standard
Straightness: 0.02mm Smoothness: Ra=0.025~0.012 Cavity surface hardness: < 0.02mm Boundary tolerances: ±0.3mm Plating thickness: 0.04-0.05mm Provide Customized Services
The FRP Round Tube Pultrusion Mould is precision tooling used to manufacture FRP (fiber-reinforced plastic) tubes. Through the pultrusion process, resin-impregnated fiber reinforcement is drawn continuously through a heated die, forming a continuous section with a fixed cross-sectional shape and size. FRP tubes offer benefits including light weight, high mechanical strength, corrosion resistance, electrical insulation, and flame resistance, and are widely adopted across the power, chemical processing, construction, and transportation industries.
How the FRP Round Tube Pultrusion Mould Works:
1. Reinforcement fiber (such as glass fiber or carbon fiber) is unspooled and guided into a resin bath for impregnation.
2. The resin-saturated fiber then passes through a preforming station, where it is shaped as needed before entering the die.
3. Inside the die, heat and pressure convert the resin from a liquid to a gel and finally to a rigid solid.
4. A pulling unit draws the cured FRP tube out of the die, and a cutting saw trims it to the required length.
Key Factors Affecting FRP Round Tube Pultrusion Mould Performance:
Fiber reinforcement: the type and content of fiber used affects mechanical properties such as strength, stiffness, and weight — generally, higher fiber content means greater strength and lower weight. Common reinforcement fibers include glass fiber, carbon fiber, and aramid fiber.
Resin system: the resin type and formulation influence chemical performance such as heat resistance, corrosion resistance, and aging resistance — a more stable resin system typically provides better long-term durability. Frequently used resins include polyester, vinyl ester, and epoxy.
Die design: the shape and dimensions of the die determine the cross-section and size of the finished profile as well as forming speed and consistency — a more precisely made die yields more uniform parts at higher efficiency.
FRP Round Tube Pultrusion Mould Specifications and Applicable Standards
| Mold name | FRP Round Tube Pultrusion Mold |
| Specification | φ38*3mm (Can be customized) |
| Material | 40Cr, P20, Cr12, 38CrMoAI, H13 (optional) |
| Cavity Surface Treatment | Quenching and tempering, quenching, hard chrome plating, nitriding |
| Cavity hardness | HRC55-60 |
| Applicable resin | Unsaturated polyester, vinyl resin, epoxy resin, phenolic resin, polyurethane |
| Straightness | 0.02mm |
| Smoothness | Ra=0.025~0.012 |
| Cavity surface hardness | < 0.02mm |
| Boundary tolerances | ±0.3mm |
| Plating thickness | 0.04-0.05mm |
Tooling Specifications & Engineering Insights
| Die Steel Grade Material | H13 Tool Steel (Premium) | Cr12MoV Die Steel (Standard) | P20 Mold Steel (Economical) |
|---|---|---|---|
| Core Working Lifespan | Excellent (Over 50,000+ meters with fiberglass) | High (Around 30,000 – 40,000 meters) | Moderate (Best for short-run prototyping) |
| Thermal Fatigue Resistance | Ultra-High (Maintains HRC hardness at high temperature) | Moderate (Good for polyester matrices) | Poor (Prone to dimensional wear under continuous PU) |
| Internal Mirror Polish Cap | Perfect (Achieves Ra 0.012 μm easily) | Excellent (Achieves Ra 0.025 μm) | Standard (Achieves Ra 0.040 μm) |
| Best Application Profiles | round tube runs requiring maximum tool life and dimensional stability | Standard-volume round tube production | Low-volume prototyping or trial runs of round tube |
Precision Mold Engineering Q&A
Q1: Why is a 0.04-0.05mm hard chrome plating thickness critical for φ38*3mm FRP Round Tube Pultrusion Mould?
Answer: Glass fiber rovings and mats are highly abrasive. During continuous pultrusion, the reinforced matrix creates significant scratching friction against the cavity walls of φ38*3mm FRP Round Tube Pultrusion Mould. A precise 0.04-0.05mm hard chrome layer raises surface micro-hardness and protects the underlying tool steel, extending die lifespan by over 40% while maintaining consistent φ38*3mm round tube geometry run after run.
Q2: How does internal mirror polishing to Ra 0.012-0.025 μm affect pull force on φ38*3mm FRP Round Tube Pultrusion Mould?
Answer: A mirror-polished cavity dramatically reduces the dynamic coefficient of friction inside the round tube shaping channel. Lower friction means the pultrusion machine needs less clamping/traction force to advance the curing composite, which cuts down on line stiction, prevents surface fiber blooming, and reduces energy consumption over long production runs.
Q3: Which steel grade should be specified for high-volume production with φ38*3mm FRP Round Tube Pultrusion Mould?
Answer: For high-volume, continuous manufacturing, H13 tool steel or Cr12MoV die steel is recommended. H13 delivers the longest working lifespan and best thermal fatigue resistance, while Cr12MoV offers strong performance at a lower cost for standard-volume runs — P20 mold steel remains a cost-effective option for prototyping or short trial batches.
Q4: Can φ38*3mm FRP Round Tube Pultrusion Mould be customized to non-standard dimensions or OEM specifications?
Answer: Yes. As with all our pultrusion tooling, dimensions, cavity count, and surface treatment can be engineered to your exact drawing or sample — our in-house CNC mold fabrication team supports both standard catalog sizes and fully custom OEM tooling requests.
Q5: Which resin systems is φ38*3mm FRP Round Tube Pultrusion Mould compatible with?
Answer: The die is compatible with the full range of resin systems used in FRP pultrusion, including unsaturated polyester, vinyl ester, epoxy, and phenolic resins. Let us know your target resin and cure profile and we can confirm the optimal cavity finish and heating zone setup.
Production Process
Engineer mould design
Profile mould debugging
Rough embryo leveling
Mold CNC machining
Mould punching
Surface grinding
Cavity inner wall polishing
Mold chrome
