Method and arrangement for manufacturing a composite part
An arrangement and method for manufacturing a composite part includes a mold, a composite material including fiber material and matrix material on a forming surface of the mold. To provide a simple and cheap technology for forming and optionally curing the component at the mold, the method includes providing a pressing tool made of semi-crystalline thermoplastic material in an amorphous state on the forming surface of the mold, forming the pressing tool by applying a pressure, that can be by expanding a hollow mandrel, and pressing the pressing tool against the mold, conducting crystallization of the pressing tool material by increasing the temperature of the pressing tool so material of the pressing tool is crystallized. Afterwards, the composite part may be hardened, such as by curing the composite part between the mold and the crystallized tube mandrel.
1 . A method for manufacturing a composite part, the method comprising sequential steps of:
a) providing a mold, which comprises a part of a pressing tool;
b) providing a composite material including a fiber material and a matrix material on a forming surface of the mold;
c) providing a hollow mandrel, which comprises another part of the pressing tool and made of semi-crystalline thermoplastic material in an amorphous state on the forming surface of the mold;
d) forming the hollow mandrel by pressing the hollow mandrel against the forming surface of the mold;
e) conducting a crystallization of the material of the hollow mandrel formed by step d), and then curing the composite material to form a cured composite part;
f) removing the hollow mandrel from the mold; and
g) removing the cured composite part from the mold after the curing of the composite material and after the hollow mandrel is removed from the mold.
2 . The method according to claim 1 , wherein:
the mold is a hollow mold;
the hollow mandrel is configured to fit inside the hollow mold;
in step d), the pressing by the hollow mandrel forms the hollow mandrel by expanding the hollow mandrel and pressing against the hollow mold; and
step e) further comprises controlling a temperature of the hollow mandrel to perform the crystallization of the semi-crystalline thermoplastic material.
3 . The method according to claim 1 , wherein, in step e), the composite material is cured between the mold and the crystallized hollow mandrel.
4 . The method according to claim 1 , wherein, in step a):
the mold comprises a cavity; and/or
the mold comprises an undercut.
5 . The method according to claim 1 , wherein, in step b):
the composite material is in a form of a laminate;
the fiber material comprises fibers and the matrix material comprises a thermo-curable resin or a thermo-plastic resin; and/or
the composite material is in a form of a prepreg material.
6 . The method according to claim 1 , wherein, in step c):
the hollow mandrel is formed as a bladder or a hose;
the providing of the hollow mandrel is at a temperature above the glass transition temperature of the semi-crystalline thermoplastic material;
the semi-crystalline thermoplastic material is selected from a group consisting of polyethelyne, polypropylene, polybutylene terephthalate, polyethylene terephthalate, and polyetheretherketone; and/or
the pressing tool comprises a skin or foil made from the semi-crystalline thermoplastic material.
7 . The method according to claim 1 , wherein step d) comprises one or more of:
increasing a pressure inside of the hollow mandrel;
pressing the fiber material and the matrix material against the forming surface of the mold; and
evacuating a region between the forming surface of the mold and the hollow mandrel, wherein the composite material is arranged within the region.
8 . The method according to claim 1 , wherein step e) comprises one or more of:
increasing a temperature of the hollow mandrel during the crystallization of semi-crystalline thermoplastic;
keeping the hollow mandrel pressed against the mold with the composite material sandwiched therebetween;
maintaining an increased pressure inside the hollow mandrel to keep the hollow mandrel pressed against the mold; and
controlling the temperature of the hollow mandrel, such that the hollow mandrel crystallizes before a final curing temperature is reached;
wherein the increasing of the temperature of the hollow mandrel is performed gradually.
9 . The method according to claim 1 , wherein the curing of the composite part between the mold and the crystallized hollow mandrel comprises:
increasing a temperature from a first temperature, at which the crystallization of the semi-crystalline thermoplastic material of the hollow mandrel occurs, to a curing temperature for the curing of the composite material; and/or
increasing and maintaining a pressure inside the hollow mandrel to press the composite material against the forming surface of the mold during the curing.
10 . The method according to claim 1 , wherein the composite material is a different material from the material of the hollow mandrel.
11 . The method according to claim 3 , wherein the matrix material is a thermo-curable matrix material.
12 . The method according to claim 1 , wherein the matrix material is a thermo-curable matrix material.
13 . The method according to claim 1 , wherein, in step a):
the mold comprises a cavity; and
the mold comprises an undercut.
14 . The method according to claim 1 , wherein, in step b):
the composite material is in a form of a laminate or a prepreg material; and
the fiber material comprises fibers and the matrix material comprises a thermo-curable resin.
15 . The method according to claim 1 , wherein, in step c):
the hollow mandrel is in a form of a bladder or a hose;
the hollow mandrel is provided at a temperature above the glass transition temperature of the semi-crystalline thermoplastic material;
the semi-crystalline thermoplastic material is selected from a group consisting of polyethylene, polypropylene, polybutylene terephthalate, polyethylene terephthalate, and polyetheretherketone; and
the pressing tool comprises a skin or foil made from the semi-crystalline thermoplastic material.
16 . The method according to claim 1 , wherein step d) comprises:
increasing a pressure inside of a portion of the pressing tool defined by the hollow mandrel;
pressing the fiber material and the matrix material against the forming surface of the mold; and
evacuating a region between the forming surface of the mold and the hollow mandrel, wherein the composite material is arranged within the region.
17 . The method according to claim 1 , wherein step e) comprises:
gradually increasing a temperature of the hollow mandrel, during the crystallization of the semi-crystalline thermoplastic material;
maintaining an increased pressure inside the hollow mandrel to keep the hollow mandrel pressed against the mold; and
controlling the temperature of the hollow mandrel, such that the hollow mandrel crystallizes before a final curing temperature.
18 . The method according to claim 3 , wherein curing the composite part between the mold and the crystallized pressing tool comprises:
increasing a temperature from a first temperature, at which the semi-crystalline thermoplastic material of the pressing tool crystallizes, to a curing temperature for curing the composite material; and
increasing and maintaining a pressure inside the pressing tool to press the composite material against the forming surface of the mold during curing.
19 . The method according to claim 1 , comprising:
removing the pressing tool; and
removing the composite part from the mold after the composite part is cured.
20 . A method for manufacturing a composite part, the method comprising sequential steps of:
a) providing a hollow mold that has a forming surface, a cavity, an undercut, and is a part of a pressing tool;
b) providing a composite material, which is in a form of a laminate or a prepreg material and includes a fiber material, which comprises fibers, and a matrix material, which is a thermo-curable resin or a thermo plastic resin, on the forming surface of the mold;
c) providing a hollow mandrel, which is another part of the pressing tool, is made of a semi-crystalline thermoplastic material in an amorphous state, is in a form of a bladder or a hose, and is configured to fit inside the hollow mold, on the forming surface of the hollow mold, wherein:
the hollow mandrel is provided at a temperature above the glass transition temperature of the semi-crystalline thermoplastic material;
the semi-crystalline thermoplastic material is selected from a group consisting of polyethylene, polypropylene, polybutylene terephthalate, polyethylene terephthalate, and polyetheretherketone; and
the pressing tool comprises a skin or foil made from the semi-crystalline thermoplastic material;
d) forming the hollow mandrel by:
pressing the hollow mandrel against the forming surface of the hollow mold;
increasing a pressure inside of the hollow mandrel;
pressing the fiber material and the matrix material against the forming surface of the hollow mold; and
evacuating a region between the forming surface of the hollow mold and the hollow mandrel, wherein the composite material is arranged within the region;
e) controlling the temperature of the hollow mandrel to perform the crystallization of the semi-crystalline thermoplastic material of the hollow mandrel by:
gradually increasing temperature of the hollow mandrel to a first temperature, at which the crystallization occurs;
maintaining the increased pressure inside the hollow mandrel to keep the hollow mandrel pressed against the hollow mold with the composite material sandwiched therebetween;
f) curing the composite part between the hollow mold and the hollow mandrel by:
increasing the temperature of the pressing tool from the first temperature to a final curing temperature;
maintaining the increased pressure inside the hollow mandrel to press the composite material against the forming surface of the mold during the curing of the composite material;
g) removing the hollow mandrel from the hollow mold; and
h) removing the composite part from the hollow mold.