Specs of FRP pultrusion machine

FRP pultrusion machine mainly consists of several different core parts. Let's take a look at the main parts.

1. Reinforcement material delivery system: such as creels, felt spreading devices, yarn holes, etc.
2. Resin impregnation: The straight groove impregnation method is the most commonly used. During the entire impregnation process, the fibers and felt should be arranged very neatly.
3. Preforming: The impregnated reinforced materials pass through the preforming device and are carefully transferred in a continuous manner to ensure their relative position, gradually approaching the final shape of the product, and extruding excess resin before entering the mold. Carry out molding and solidification.
4. Mold: The mold is designed under the conditions determined by the system. According to the resin curing exothermic curve and the friction properties between the material and the mold, the mold is divided into three different heating zones, and their temperatures are determined by the properties of the resin system. The mold is the most critical part of the pultrusion process. The length of a typical mold ranges from 0.6 to 1.2m.
5. Traction device: The traction device itself can be a crawler-type puller or two reciprocating clamping devices to ensure continuous movement.
6. Cutting device: The profile is cut to the required length by an automatically synchronously moving cutting saw.

The function of the forming mold is to achieve compaction, shaping and solidification of the blank. The mold cross-section size should consider the molding shrinkage of the resin. The length of the mold is related to the curing speed, mold temperature, product size, pultrusion speed, reinforced material properties, etc., and is generally 600 to 1200mm.

The finish of the mold cavity should be high to reduce friction, extend service life, and make demoulding easy. Electric heating is usually used, and microwave heating is used for high-performance composite materials. A cooling device is required at the entrance of the mold to prevent the glue from solidifying prematurely. The dipping process mainly controls the relative density (viscosity) of the glue and the dipping time. The requirements and influencing factors are the same as for prepreg.

The curing molding process mainly controls the molding temperature, mold temperature distribution, and the time for the material to pass through the mold (pultrusion speed). This is the key process of the pultrusion molding process. During the pultrusion process, a series of complex physical, chemical and physicochemical changes occur in the prepreg as it passes through the die, which are still not well understood.