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Classification And Characteristics Of Winding Forming Process

Jul 26, 2020

The winding molding process is to wind the continuous fiber (or cloth tape, prepreg yarn) impregnated with resin glue on the core mold according to a certain rule, and then solidify and demold to obtain the product.

According to the different physical and chemical states of the resin matrix during fiber winding molding, there are three types: dry winding, wet winding and semi-dry winding.

(1) Dry winding Dry winding uses prepreg yarn or tape treated with prepreg, which is heated and softened to a viscous fluid state on a winding machine and then wound onto the core mold. Since the prepreg yarn (or tape) is professionally produced, the resin content (accurate to within 2%) and the quality of the prepreg yarn can be strictly controlled. Therefore, dry winding can accurately control product quality. The biggest feature of the dry winding process is high production efficiency, winding speed up to 100-200m/min, clean winding machine, good labor and hygiene conditions, and high product quality. The disadvantage is that the winding equipment is expensive, and the prepreg yarn manufacturing equipment needs to be added, so the investment is relatively large. In addition, the interlayer shear strength of dry winding products is low.

Winding process diagram

(2) Wet winding Wet winding is to dipped the fiber bundle (yarn-like tape) and then directly wind it on the mandrel under tension control. The advantages of wet winding are:

①The cost is 40% lower than that of dry winding;

②The product has good air tightness, because the winding tension causes the excess resin glue to squeeze out the bubbles and fill the gaps;

③Good parallelism of fiber arrangement;

When wet winding, the resin glue on the fiber can reduce fiber wear;

⑤High production efficiency (up to 200m/min).

The disadvantages of wet winding are:

①Large resin waste and poor operating environment;

②It is not easy to control the glue content and the quality of finished products;

③There are fewer resin varieties available for wet winding.

(3) Semi-dry winding: After the fiber is dipped, a set of drying equipment is added to remove the solvent in the dipped yarn. Compared with the dry method, it saves the need Dipping process and equipment; compared with wet method, can reduce the content of bubbles in the product.

Among the three winding methods, wet winding is the most common application; dry winding is only used in high-performance, high-precision cutting-edge technology