Production Methods

Hand Laying

It is the most widely used method for large surface FRP molding. Gelcoat is applied after the mold release agent is applied. After hardening of the gelcoat layer, fiberglass is applied with a polyester brush or wool roller. With hand lay-up, a molding method requiring low fixed capital investment, 25-35% glass fiber reinforced polyester products can be obtained. Since it is a labor-intensive production method, capacity depends on the number of labor and molds. An average of 2 products can be obtained from one mold.

Pultrusion

It is based on the principle that continuous glass fiber rovings are passed through a polyester bath and then hardened while being drawn through a hot mold in the desired profile. In the direction of fiber reinforcement, very durable profile products with a very high glass fiber ratio are obtained.

RTM/Light RTM Resin Injection

In this production method, two smooth products are obtained by using two molds, male and female. RTM fiber etc. between two separate molds designed for RTM. reinforcements are placed and the molds are closed. From a pre-prepared injection point, a pressure controlled RTM Machine injects the resin into the closed molds. Compared to hand lay-up, productivity and product quality are higher with RTM. With this method, large and complex parts as well as sandwich products can be molded in a single process and different wall thicknesses can be achieved in different areas. As a result of the exothermic reaction, the heat generated due to the hardening of the resin will also heat the mold, providing an advantage in molding time. Since the resin is cured in a closed environment, the RTM method releases less chemical vapors into the environment.

SMC/BMC Pre-Molding

It is a fast molding method that provides a molding time of 3-6 minutes depending on the product size. It is a method of shaping the mixture of glass fiber, polyester-filler and additives in the form of pre-prepared pulp or dough in steel molds at a temperature of 150-170 °C under a pressure of 50-120 kgf/cm².

Fiber Wrapping

It is a molding method used especially for pipe and tank production. Continuous fiber rovings are wetted in a resin bath and then wound at certain angles on a rotating mold. It is an automatable process. It is used in the production of pressure tanks, chemical tanks, infrastructure and industrial pipelines, aircraft and wind turbine parts.

Fiber Spraying – Spray Up

It is a molding method that allows the hand lay-up method to be applied more serially. During production, polyester and glass fiber are sprayed onto the mold with the help of a special machine. In the spraying method, a continuous glass fiber roving is used by trimming it to 17-50 mm in length during the spraying process. It provides mass production and labor saving in products with large surfaces.

Vacuum Infusion

The method of wetting the fibers laid dry in the mold with resin under vacuum pressure is called infusion. In addition to the selection of the appropriate resin and fiber, the use of the right consumables is crucial for successful infusion applications. Suitable for the production of performance parts that are planned to be produced in small quantities. It cannot be automated, but it is the process that provides the most flexibility in terms of mold geometry and size scaling among composite production methods.

Thermoplastic Injection/ Extrusion

Extrusion machines are used for molding profile type products, while injection machines are used for molding complex shaped products. Injection and extrusion machines work similarly in principle. The resin, which is introduced into the machine from the feed hopper in granule form, is heated in a heating zone to make it fluid and transported to the outlet end by means of auger grooves while ensuring homogeneous mixing on the one hand.

In extruders, profiles are drawn in accordance with the mold shape with the help of pressure effect and pulling apparatus through the mold placed at the outlet end, while in injection machines, a fluidized thermoplastic resin is injected into the closed mold located right next to the outlet nozzle and cooled and hardened in the closed mold.