The Infusion Method

The infusion method consists in arranging a dry reinforcement to the mold with a previously applied gel coat, laying the delamination fabric and the mesh and installation distributing the resin, the vacuum collecting plant, closing the mold with a vacuum bag. After checking the tightness of the bag to the points of incorporation of the mixture, the prepared (mixed with the hardener) resin is connected. By means of the pressure difference between the resin inlet and the vacuum collection plant, the mix is sucked in between the vacuum bag and the mold and rolled over the entire mold surface [15].

As a reinforcement in the method of infusion, continuous filament fabrics, three-dimensional fabrics or matte fabrics intended for the infusion process are used. Their special design allows the mixture to flow and allows for less wear, which at the same time translates into a greater contribution of reinforcement. Very often, in order to increase the thickness of the laminate, while maintaining a low mass, cuttings of balsa, polymer foams (PVC, PET) and honeycomb parts are introduced.

The infusion method allows the production of products with a complex geometry as well as large dimensions in one technological stage. In this case, a volume gain of 50-65% is obtained. The pressures used in this method change during the process. At the beginning, the average pressure is from -4.0 to -0.5 MPa, and then, after filling about 60-70% of the mold, it is increased to the range of -0.8 to -0.9 MPa and maintained until the gelation mixture (it ceases to flow).

The advantage of this method is the ease and repeatability of the production of products, even of large dimensions, short production cycle, the integrity of elements, such as ribs or cores, possible to be introduced in one technological stage. The obtained products are characterized by very good and repeatable mechanical properties, a small number of defects in the composite structure, high repeatability and dimensional stability. The advantage of this method is also the reduction of emission of harmful substances during the production of products.

The disadvantages of the infusion method include the large cost of production tooling in large series, which makes it a cost-effective method for the manufacture of a smaller series of products.

Infusion is a technologically advanced process that allows a high ratio of the reinforcement to the warp ratio, which translates into gainig better mechanical properties.

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