GB/T 4550-2026Preparation of fibre reinforced plastic plates for test purposes (English PDF)

5.1 Winding Equipment

5.1.1 Wrapping Machine It consists of a yarn frame, a tension control device, a glue tank, and a circumferential winding drive mechanism (a glue tank is not required for dry winding).

5.1.2 Yarn Frame Used to hold fiber yarn balls, it can be placed upright or horizontally. The yarn ball axis should have a certain braking force to prevent the yarn ball from loosening.

5.1.3 Tension Control Device Mechanical friction or electromagnetic force methods can be used. The tension should remain stable throughout the winding process, ideally at 2% to 4% of the fiber's ultimate strength.

5.1.4 Glue Tank It should be equipped with a temperature control device. It mainly consists of an inlet winding nozzle, extrusion roller, dipping roller, and guide roller. See Figure 2 for a schematic diagram.

5.1.5 Drive Mechanism The fibers are evenly and parallelly distributed across the surface of the mandrel, with a rotation speed of 0 r/min to 30 r/min.

5.2 Curing Equipment

5.2.1 Oven or press It should have a temperature control device that meets the curing requirements, with a temperature control accuracy of ±3°C.

5.2.2 Autoclave The autoclave must meet the following requirements.

a) It should have a temperature control system that meets the curing requirements, with a temperature control capacity of not less than.200°C and a temperature control accuracy of ±3°C;

b) It should have a pressure control system that can meet the curing requirements, with a pressure control capacity of not less than

0.7 MPa and a pressure control accuracy of ±

0.02 MPa.

5.3 Mold

5.3.1 Molds for the winding-molding method and the winding-autoclave method The winding die consists of a core mold and upper and lower pressure plates. The dimensions and precision requirements of the die are shown in Figure 3.

5.3.2 Molds for the lay-up-molding method and the lay-up-autoclave method The mold for prepreg laying consists of a flat mold and two pressure plates, one above the other. A winding mold with the recommended form and precision is preferred.

5.4 Vacuum System The vacuum system should ensure that the relative vacuum pressure inside the vacuum bag is less than -94 kPa.

7.1 Winding-molding method

7.1.1 State Adjustment The fibers are conditioned according to the specifications in the technical documents.

7.1.2 Material Calculation The number of winding layers is calculated according to formula (1).

7.1.3 Entanglement

7.1.3.1 Install the mandrel coated with release agent onto the mandrel of the winding machine.

7.1.3.2 Adjust the temperature of the mandrel to be close to that of the adhesive solution; the temperature difference should not exceed ±5°C.

7.1.3.3 Pour the adhesive into the adhesive tank and adjust the adhesive to the specified temperature.

7.1.3.4 Draw the fiber end from the yarn frame and pass it sequentially through the dipping roller, extrusion roller, and winding nozzle, finally fixing it onto the mandrel. Recommended fiber... The method of extraction is external exit.

7.1.3.5 Adjust the tension control device to ensure that the fiber tension meets the process requirements.

7.1.3.6 Wrap to the specified number of layers and bake while rotating to ensure the adhesive evenly penetrates the fibers. The baking temperature should be based on the technical documents. Sure.

7.1.4 Curing

7.1.4.1 Place the wound flat plate along with the mandrel between the two pressure plates, and place thickness control pads at the four corners. Use a press. During curing, the material is placed directly into a press, and pressure is applied to bring the upper and lower pressure plates of the mold into contact with the pads. Finally, the fibers at both ends of the core mold are cut. An oven is used. During curing, bolts are used to tighten and pressurize the core mold, bringing the pressure plate into contact with the pad. Finally, the fibers at both ends of the core mold are cut off and the mold is placed in an oven.

7.1.4.2 Curing shall be carried out at the specified temperature and time.

7.1.4.3 After naturally cooling to room temperature, disassemble the mold and remove the flat plate. Clean the mold and release sheet for later use.

7.1.5 Trimming Trim the removed plate and cut off a 15mm wide edge.

7.2 Winding-Autoclave Method

7.2.1 State Adjustment The fibers are conditioned according to the specifications in the technical documents.

7.2.2 Material Calculation The number of winding layers is calculated according to formula (1).

7.2.3 Entanglement

7.2.3.1 As specified in 7.1.3.

7.2.3.2 After winding, allow the resin to impregnate the fibers and expel some air bubbles for a period of time at room temperature or slightly higher. Then, place the mold... The upper and lower pressure plates are assembled and pressed together with the wound mandrel. A vacuum bag system is constructed using materials such as breathable felt and vacuum bags, and then placed in a heat press. Inside the jar.

7.2.4 Vacuum Leak Detection A complete vacuum is drawn, with a relative vacuum pressure of at least -80 kPa. Before leak testing, the parts must be connected to the vacuum system for at least 15 minutes. (Close) When shutting down the vacuum line, check for leaks in each component. The vacuum level should be as specified in the technical documentation; if no specific specifications are provided, it is recommended to check the vacuum level within 5 minutes. The air pressure decreases by no more than 17 kPa.

7.2.5 Curing Curing should be performed according to the specifications in the technical documents; if no specific specifications are provided, a heating rate of 1°C/min to 4.5°C/min is recommended. Curing Then, it is cooled to room temperature under pressure in an autoclave. The assembly is then removed from the autoclave, and the plate is taken out.

7.2.6 Trimming According to the provisions of 7.1.5.

7.3 Laying-molding method

7.3.1 State Adjustment Remove the prepreg sealed bag from the low-temperature chamber and place it in an environment with a temperature of (23±2)°C and a relative humidity of (50±10)% for condition conditioning. Section. When the amount of prepreg in the bag is no more than 1 kg, the storage time shall be no less than 1 hour; when the amount is more than 1 kg, the storage time shall be no less than 2 hours.

7.3.2 Material Calculation The number of prepreg layers is calculated according to formula (2).

7.3.3 Laying

7.3.3.1 Check the consistency of the materials and ensure there are no inclusions or other defects.

7.3.3.2 Before laying, cut the single layer to the specified size. It is advisable to use an automatic cutting machine to ensure the tolerance of the stack size and fiber orientation.

7.3.3.3 Apply a release agent to the metal mold. Align the first layer in the layup sequence with its corresponding fiber direction.

7.3.3.4 Lay the cut prepreg layers together in the specified direction, with an angular error not exceeding ±1°.

7.3.4 Curing Place the upper metal platen of the mold on the combination of the metal bottom template and the prepreg blank, pre-tighten the cold-sealing bolts, and then place it in the curing oven for preheating. Once the desired temperature is reached, place it on a press for mold closing and curing. Cure according to the specifications in the prepreg technical documentation. Allow to cool naturally to room temperature. Next, disassemble the mold and remove the flat plate. Clean the mold and set it aside for later use.

7.3.5 Trimming According to the provisions of 7.1.5.

7.4 Installation - Autoclave Method

7.4.1 State Adjustment As per 7.3.1.

7.4.3 Laying

7.4.3.1 Cut the prepreg to 400mm×400mm. The number of prepreg layers is calculated according to formula (2).

7.4.3.2 Apply the release agent to the metal bottom template and the metal top platen, and lay them according to the specifications in 7.3.3.

7.4.3.3 Calculate the required amount of absorbent material according to formula (3). The size of the absorbent material is 400mm×400mm.

7.4.3.4 The prepreg blanks and auxiliary materials shall be combined in the following order.

a) Place an insulating film on the metal base template;

b) Lay a layer of perforated release cloth on both the upper and lower surfaces of the prepreg blank;

c) Place adhesive-absorbing material on the metal base template release film. When the total number of adhesive-absorbing material layers is odd (2n+1), it can be applied to the prepreg. Lay (n+1) layers sideways; simultaneously, lay baffles around the perimeter of the prepreg stack;

d) Place the perforated insulating layer and the metal pressure plate in sequence;

e) Apply sealing tape between the perimeter of the metal upper pressure plate and the metal bottom template.

7.4.3.5 Place the prepreg blank and auxiliary material assembly on the metal substrate in the autoclave, and lay the breathable material and vacuum bag as shown in Figure 1. Materials and sealing strips.

7.4.4 Vacuum Leak Detection After the flat panels are laid out, seal them in bags and completely vacuum-seal them. Once the vacuum bags for each test panel are completely vacuum-sealed, shut off the vacuum line and inspect. Leakage of each component. Vacuum level as specified in the technical documentation; if no specific specifications are provided, a vacuum level drop of no more than [value missing] within 5 minutes is recommended. 17 kPa.

7.4.5 Curing Curing is performed according to the specifications in the prepreg technical documentation. After curing, the prepreg is cooled to room temperature under pressure in an autoclave. The assembly is then removed from the autoclave. Press the can and remove the flat plate.

7.4.6 Trimming According to the provisions of 7.1.5.

8.2 Measure the length of the four sides, accurate to

0.5 mm.

8.3 Measure the thickness of the plate at each corner 25mm from the edge and at the center, accurate to 0.01mm.

8.4 Use non-destructive testing to inspect defects in flat plates.

8.5 The fiber volume content of the flat plate was tested.

9.Preparation of Flat Plate Report The report should include all or part of the following.

a) This document number;

b) The unit and date of preparation of the plate;

c) The appearance, dimensions, thickness, number of winding layers, number of prepreg layers, and fiber volume fraction of the flat sheet;

e) Resin grade and curing regime;

f) The preparation method of the prepreg, for lay-up-molding and lay-up-autoclave methods, should also specify the grade, specifications, and source of the prepreg. batch number;

g) Other instructions.