Long Heated Pultrusion Die

Long heated pultrusion die is an extended die block with multiple heating zones, designed for high-speed production of large or thick-wall FRP profiles. The die is shown as a row of tall steel blocks mounted on a heated platen, each with a profiled cavity and feed chute on top.

Multi-zone Heating Design

Unlike a short single-zone die, the long die has several independently controlled heating zones along its length. The entrance zone preheats the resin-impregnated glass, the middle zone controls the cure reaction, and the exit zone holds the profile at temperature to ensure complete curing before it contacts the puller. This extended heating length allows faster line speeds and thicker wall sections.

Construction

• Multiple steel die blocks mounted on a common heated bed.

• Top-mounted feed chutes for glass rovings and mat.

• Independent temperature control for each zone.

• Replacement wear plates at high-friction points.

• Robust frame for long-term continuous operation.

Benefits

A long die increases production rate by allowing faster puller speed without sacrificing cure quality. It also reduces the risk of under-cured profiles, which would be too flexible or weak. For thick-wall profiles (8 mm and above), the extended die length is essential to bring the core temperature up to cure temperature before the profile exits.

Applications

Long heated dies are used for production of large structural profiles, thick-wall tubes, heavy I-beams, and large rectangular hollow sections for bridges, cooling towers, and offshore platforms. They are also used for pultrusion of flame-retardant and fire-rated profiles where cure control is critical.

Conclusion

The long heated pultrusion die is a high-productivity tool for large and thick FRP profiles. Multi-zone temperature control and extended die length are key to achieving fast, consistent, and complete cure at high line speeds.