Method and apparatus for manufacturing composite material
A method of manufacturing a composite material through a wet compression molding (WCM) process is disclosed. The internal pressure of a mold is controlled so that productivity may be improved due to process automation through application of a resin using a robot. Quality of the composite material may be improved due to minimization of deformation of a foam core through control of the internal pressure of the mold.
1 . A method of manufacturing a composite material, the method comprising:
applying, using a resin injector, a resin to an upper surface of a preform having at least one fiber and foam;
executing, using a press, compression molding of the preform having the resin applied thereto by lowering an upper slide of a mold and raising a lower slide of a mold;
determining, using a pressure sensor, whether or not an internal pressure of the mold exceeds a predetermined pressure value; and
controlling the internal pressure of the mold by reducing a raising speed of the lower slide in real-time upon determining that the internal pressure of the mold exceeds the predetermined pressure value,
wherein compressive strength of the foam is in a range of 10 bar to 100 bar.
2 . The method of claim 1 , wherein the fiber comprises at least one of glass fiber, carbon fiber, boron fiber, regenerated fiber, or any combination thereof.
3 . The method of claim 1 , wherein the fiber is provided in a form of at least one of unidirectional fabrics, woven fabrics, or any combination thereof.
4 . The method of claim 1 , wherein the resin comprises at least one of bisphenol epoxy resins, polyester resins, polyurethane resins, or any combination thereof.
5 . The method of claim 1 , wherein a gel time of the resin is in a range of 10 seconds to 2 minutes.
6 . The method of claim 1 , wherein the preform comprises a first layer having a first fiber, a second layer disposed on the first layer and having a second fiber, and a third layer disposed on the second layer and having a third fiber.
7 . The method of claim 1 , wherein applying the resin to the upper surface of the preform further comprises:
applying, by a robot of the resin injector, the resin to the preform by moving a mixing head mounted on the robot; and
determining whether or not an error occurs in the robot.
8 . The method of claim 1 , wherein executing the compression molding of the composite material further comprises:
raising the lower slide at a speed in a range of 50 millimeters per second (mm/s) to 100 mm/s when a gap between the upper slide and the lower slide is in a range of 5 millimeters (mm) to 10 mm, and raising the lower slide at a speed in a range of 0.5 mm/s to 1.0 mm/s when the gap between the upper slide and the lower slide is in a range of 2 mm to 5 mm; and
executing the compression molding of the preform.
9 . The method of claim 1 , further comprising:
after executing the compression molding of the preform, impregnating the preform with the resin by allowing the resin applied to the upper surface of the preform to flow downwards from an interior of the preform.
10 . The method of claim 1 , further comprising:
upon determining that the internal pressure of the mold exceeds the predetermined pressure value, controlling the internal pressure of the mold by adjusting a gap of the mold by increasing a gap between the upper slide and the lower slide.
11 . The method of claim 1 , wherein controlling the internal pressure of the mold by reducing the raising speed of the lower slide further comprises:
reducing the internal pressure of the mold by adjusting the raising speed of the lower slide to 0.01 mm/s to 0.50 mm/s.
12 . The method of claim 1 , further comprising:
after controlling the internal pressure of the mold, additionally controlling the internal pressure of the mold,
wherein additionally controlling the internal pressure of the mold includes
lowering the lower slide, when the internal pressure of the mold exceeds the predetermined pressure value.
13 . The method of claim 12 , wherein lowering the lower slide further comprises:
reducing the internal pressure of the mold by adjusting a gap between the upper slide and the lower slide by 0.01 mm to 0.10 mm.
14 . The method of claim 12 , further comprising:
after additionally controlling the internal pressure of the mold, and upon determining that the internal pressure of the mold becomes equal to or less than the predetermined pressure value, manufacturing the composite material by curing the preform having the resin applied thereto while maintaining the internal pressure of the mold at the predetermined pressure value or below.
15 . A method of manufacturing a composite material, the method comprising:
applying, using a resin injector, a resin to an upper surface of a preform having at least one fiber and foam;
executing, using a press, compression molding of the preform having the resin applied thereto by lowering an upper slide of a mold and raising a lower slide of a mold;
determining, using a pressure sensor, whether or not an internal pressure of the mold exceeds a predetermined pressure value; and
controlling the internal pressure of the mold by reducing a raising speed of the lower slide in real-time upon determining that the internal pressure of the mold exceeds the predetermined pressure value,
wherein executing the compression molding of the composite material further comprises:
raising the lower slide at a speed in a range of 50 millimeters per second (mm/s) to 100 mm/s when a gap between the upper slide and the lower slide is in a range of 5 millimeters (mm) to 10 mm, and raising the lower slide at a speed in a range of 0.5 mm/s to 1.0 mm/s when the gap between the upper slide and the lower slide is in a range of 2 mm to 5 mm; and
executing the compression molding of the preform.
16 . A method of manufacturing a composite material, the method comprising:
applying, using a resin injector, a resin to an upper surface of a preform having at least one fiber and foam;
executing, using a press, compression molding of the preform having the resin applied thereto by lowering an upper slide of a mold and raising a lower slide of a mold;
determining, using a pressure sensor, whether or not an internal pressure of the mold exceeds a predetermined pressure value; and
controlling the internal pressure of the mold by reducing a raising speed of the lower slide in real-time upon determining that the internal pressure of the mold exceeds the predetermined pressure value,
wherein controlling the internal pressure of the mold by reducing the raising speed of the lower slide further comprises:
reducing the internal pressure of the mold by adjusting the raising speed of the lower slide to 0.01 mm/s to 0.50 mm/s.