Methods for the serial production of flat fiber-reinforced plastic composite components

Abstract

Method for the serial production of planar fiber-reinforced plastic components (B) with a device (100) comprising a press tool (120) in which the fiber-reinforced plastic components (B) are produced and a cooling tool (130) in which the produced fiber-reinforced plastic components (B) are cooled in a defined manner, which are jointly arranged in a press chamber (111) of a press, wherein the method provides for the division of the curing of the fiber-reinforced plastic components (B) into a pre-curing and a final curing, such that simultaneously during a pressing pass in the press tool (120) a fiber-reinforced plastic component (B') is produced and pre-cured and in the cooling tool (130) the fiber-reinforced plastic component (B') produced and pre-cured in the press tool (120) in the preceding pressing pass is cured and cooled.

Description

[0001] The invention relates to a method for the serial production of flat fiber-reinforced plastic composite components.

[0002] Various processes for manufacturing planar and three-dimensional fiber-reinforced plastic (FRP) components are known from the prior art, as described, for example, in DE 10 2013 223 318 A1. Common manufacturing processes include compression molding, in particular hot and wet compression molding, prepreg molding, and resin transfer molding (RTM). These processes have in common that fiber material (e.g., in the form of woven fabrics, nonwovens, laid fabrics, mats, or preforms) is placed together with matrix or polymer compound into the cavity of a mold or press tool and then pressed into a predefined component shape, a process also referred to as compression molding. During compression molding, matrix compound is distributed in the cavity, embedding the reinforcing fibers and then hardening.

[0003] Hot pressing also requires cooling. A separate cooling tool is often used for this purpose. The molding process involves compression molding, matrix distribution, and curing. In the cooling tool, the fiber-reinforced composite component, previously produced in the mold, is cooled to a defined target or removal temperature, thereby maintaining its shape and / or correcting its geometry.

[0004] The closest patent, DE 10 2010 063 751 A1, describes a process for manufacturing lightweight components with a high natural fiber content. The process comprises the following steps: a) Inserting a natural fiber semi-finished product into an injection mold; b) Pressing and / or forming and consolidating the natural fiber semi-finished product into a molded part in the injection molding tool; c) back-side or attachment-side injection molding of fasteners and / or reinforcing structures onto the molded part; and d) application of a surface component to the visible side in a specified area of ​​the molded part.

[0005] This process is preferably carried out in a rotary insert injection molding machine, with the steps being split. Steps a), b), and c) are performed on one side of the insert. The insert, together with the molded part, is then rotated 180° and step d) is performed on the other side. In series production, step d) can thus be performed in parallel with steps a), b), and c).

[0006] For the state of the art, reference is also made to DE 10 2008 047 564 A1, US 2006 / 0118999 A1 and DE 10 2005 050 925 A1.

[0007] Based on this, the invention is intended to demonstrate a way in which the mass production of flat fiber-reinforced plastic composite components can be optimized.

[0008] This is achieved with the inventive method of claim 1. Preferred further developments and embodiments result from both the dependent claims and the following explanations.

[0009] An apparatus used to carry out the method according to the invention comprises a press tool in which the fiber-reinforced composite components are produced (e.g., by wet pressing, prepreg pressing, resin transfer molding, or the like), and a cooling tool in which the produced fiber-reinforced composite components are cooled in a controlled manner. The apparatus further comprises a press, in particular a hydraulic press. It is provided that the press tool and the cooling tool are arranged together in the press chamber of the press, so that within one press closing stroke or pressing pass, and thus simultaneously, a fiber-reinforced composite component can be produced and a fiber-reinforced composite component produced in the preceding pressing pass can be cooled (su).

[0010] Advantageously, only one press is required, thus keeping investment costs, operating costs, and space requirements low. Furthermore, the simple and rapid transfer of a fiber-reinforced composite component produced in the mold or press tool to the cooling tool is enabled, whereby, according to the invention, the fiber-reinforced composite component is not yet fully cured, but only pre-cured. The curing process is therefore split into pre-curing (in the press tool) and final curing (in the cooling tool). This allows for a significant reduction in cycle time. Up to now, the cycle time has been determined by the considerably longer compression molding process, since almost complete curing is required to transfer the produced fiber-reinforced composite component to the cooling tool.

[0011] Preferably, the pressing tool and the cooling tool are arranged one above the other in the press chamber. This means that the pressing tool and the cooling tool are essentially positioned in a row between the press ram and the press table and are subjected to a common pressing force. Such an arrangement can also be described as a stacked or tiered arrangement. If the press table is sufficiently large, several stacks of tools can also be arranged side by side.

[0012] Preferably, the pressing tool is arranged at the bottom of the stack and the cooling tool at the top. This allows easier access, especially manual access, to the pressing tool. Furthermore, supplying the lower tool, e.g., adding resin in the RTM process, is easier than supplying the upper tool. In principle, of course, a reverse arrangement is also possible, with the cooling tool at the bottom and the pressing tool at the top.

[0013] Preferably, the upper tool part of the lower tool, in particular the pressing tool, and the lower tool part of the upper tool, in particular the cooling tool, are essentially identical and are attached on both sides to an intermediate plate pivotably arranged in the press chamber between the pressing tool and the cooling tool, so that these identical tool parts can interact alternately with the upper tool part of the upper tool, which is attached to the press ram, and with the lower tool part of the lower tool, which is attached to the press table, by pivoting the intermediate plate.

[0014] The device may include a pivoting mechanism for the intermediate plate, allowing the intermediate plate, along with the tool components attached to it, to be pivoted. The pivoting mechanism may be hydraulically, pneumatically, and / or electrically driven.

[0015] The pressing tool can have at least one heating device and / or the cooling tool can have at least one cooling device. If the pressing tool is located at the bottom and the cooling tool at the top, it is preferred that only the lower part of the pressing tool, which is mounted on the press table, is equipped with (at least) one heating device and / or that only the upper part of the cooling tool, which is attached to the press ram, is equipped with (at least) one cooling device. The same applies analogously if the pressing tool is located at the top and the cooling tool at the bottom. When using the intermediate plate described above, the tool parts attached to this intermediate plate can thus remain free of heating and / or cooling devices, so that no pivoting connections are required.

[0016] The inventive method for the serial production of flat fiber-reinforced plastic composite components involves the use of a device as described above, wherein, during a pressing cycle, a fiber-reinforced plastic composite component is simultaneously produced and pre-cured in the pressing tool, and the fiber-reinforced plastic composite component previously produced and pre-cured in the pressing tool (i.e., in the preceding pressing cycle) is final-cured and cooled in the cooling tool. The production of the fiber-reinforced plastic composite components thus takes place in two successive sub-processes, wherein the compression molding and pre-curing in the pressing tool (first sub-process) and the final-curing and cooling in the cooling tool (second sub-process) necessarily occur with the same cycle time.

[0017] When using an intermediate plate, as explained above, it is preferably provided that after a pressing cycle, the press is opened and the cured and cooled fiber-reinforced composite component is first removed from the cooling die, either manually or automatically. The intermediate plate is then pivoted, possibly after being lifted, together with the attached die parts. The fiber-reinforced composite component produced and pre-cured in the press die remains in the die part of the press die attached to the intermediate plate and is carried along during the pivoting process, so that it is then located in the cooling die for the subsequent pressing cycle. Thus, removing the component from the press die and placing it in the cooling die is not necessary.The transfer from the pressing tool to the cooling tool is carried out by pivoting the intermediate plate, whereby the fiber-reinforced plastic composite component previously produced in the pressing tool and only pre-hardened is held in the relevant tool part, e.g. by negative pressure or vacuum suction, and is supported, for example, on its cavity surface, so that it cannot deform.

[0018] The invention is explained in more detail below with reference to the drawing. Fig. Figure 1 schematically shows a device and illustrates in several individual figures a sequence according to the invention for the series production of planar fiber-reinforced plastic composite components with this device.

[0019] The device 100 comprises a pressing tool 120 and a cooling tool 130, which are arranged one above the other in the press chamber 111 of a press (not shown in detail) with a press table 112 and a press ram 113. The pressing tool 120 can also be an RTM tool. Furthermore, both tools 120 and 130 can be multi-cavity tools (with several mold cavities).

[0020] The lower tool part 121 of the pressing tool 120 is mounted on the press table 112 and has a heating element 123. The upper tool part 132 of the cooling tool 130 is mounted on the press ram 113 and has a cooling element 133. The upper tool part 122 of the pressing tool 120 and the lower tool part 131 of the cooling tool 130 are identical and are mounted opposite each other on the two sides of a pivotable intermediate plate 140. By pivoting the intermediate plate 140 together with the tool parts 122 and 131 attached to it, these tool parts can interact alternately with the lower tool part 121 of the pressing tool 120 and the upper tool part 132 of the cooling tool 130. The upper tool part of the pressing tool 120 can form the lower tool part of the cooling tool 130 and vice versa.

[0021] With the device 100, a fiber-reinforced plastic composite component B' can be produced and pre-cured simultaneously within a single press closing stroke or press pass in the press tool 120, and the fiber-reinforced plastic composite component B produced in the preceding press pass can be fully cured and cooled in the cooling tool 130, as shown in Fig. Figure 1a shows the pressing force F acting on both tools 120 and 130.

[0022] After one pressing cycle, the press is opened by lifting the press ram 113 and the hardened and cooled fiber-reinforced composite component B can be removed from the cooling tool 130, as shown in Fig. 1b shown.

[0023] The intermediate plate 140, together with the attached tool parts 122 and 131, is then moved upwards, which is done using the in Fig. The lifting mechanism 150, shown in dashed lines in Figure 1c, can be achieved. The press tool 120 opens, and the produced and pre-hardened fiber-reinforced plastic composite component B' remains attached to the upper part of the tool 122. This can be accomplished, for example, by means of a vacuum suction.

[0024] Now the intermediate plate 140, together with the attached tool parts 122 and 131, is pivoted, as illustrated by arrow S. In doing so, the fiber-reinforced composite component B' is carried along and is then located opposite the upper part 132 of the cooling tool 130, as shown in Fig.Figure 1d shows that the pivoting of the intermediate plate 140 can be accomplished using the pivoting mechanism 160, which is shown only schematically. New fiber material M is inserted into the open press tool 120 at the bottom before the intermediate plate 140 is actively or passively lowered and another pressing cycle is performed. In this case, the upper part 122 of the press tool 120 now forms the lower part of the cooling tool 130. The subsequent process is repeated cyclically according to the preceding explanations, with the intermediate plate 140 being pivoted 180° after each pressing cycle.

[0025] The assignment of tool parts 122 and 131 to one of the tools 120 or 130 is irrelevant due to their essentially identical design. The two tool parts 122 and 131, which are attached to the intermediate plate 140, can therefore also be described as intermediate or swivel tools (without a specific assignment to one of the tools). In an equivalent embodiment, these tool parts 122 and 131 are connected to each other without the intermediate plate 140 and are particularly designed as a single tool part, with the intermediate plate 140 being preferred, among other reasons, because of the flexibility it provides.

[0026] The invention is particularly suitable for the serial production of small to medium-sized fiber-reinforced plastic composite components, and in principle, large fiber-reinforced plastic composite components can also be produced according to the invention. Removal and insertion can be carried out manually or automatically, e.g., by means of a robot or the like. Reference symbol list 100 Device 111 Press room 112 Press table 113 press rams 120 Press tools 121 Tool base 122 Tool top 123 Heating system 130 Cooling tool 131 Tool base 132 Tool top 133 Cooling unit 140 intermediate plate 150 lifting mechanism 160 swivel mechanism B, B' Fiber-reinforced plastic composite component F Pressing force M Fiber material S swivel movement

Claims

[1] Method for the serial production of planar fiber-reinforced plastic components (B) with a device (100) comprising a press tool (120) in which the fiber-reinforced plastic components (B) are produced and a cooling tool (130) in which the produced fiber-reinforced plastic components (B) are cooled in a defined manner, which are jointly arranged in a press chamber (111) of a press, wherein the method provides for the division of the curing of the fiber-reinforced plastic components (B) into a pre-curing and a final curing, such that simultaneously during a pressing pass in the press tool (120) a fiber-reinforced plastic component (B') is produced and pre-cured and in the cooling tool (130) the fiber-reinforced plastic component (B') produced and pre-cured in the press tool (120) in the preceding pressing pass is cured and cooled. [2] The method of claim 1, wherein the pressing tool (120) and the cooling tool (130) are arranged one above the other in the press chamber (111) of the press, such that the upper tool part (122) of the lower tool (120) and the lower tool part (131) of the upper tool (130) are identical and are attached on both sides to an intermediate plate (140) pivotably arranged in the press chamber between these tools (120, 130), so that these tool parts (122, 131) can interact alternately with the upper tool part (132) of the upper tool (130) attached to a press ram (113) and the lower tool part (121) of the lower tool (120) attached to a press table (112), wherein the method provides that after a pressing pass, the cured and cooled fiber-reinforced composite component (B) is first removed from the The cooling tool (130) is removed, and then the intermediate plate (140) together with the tool parts (122, ) attached to it is removed.131) is pivoted so that the fiber-reinforced composite component (B') produced and pre-hardened in the press tool (120) remains in the tool part (122) of the press tool (120) attached to the intermediate plate (140) and is carried along during pivoting (S) and is then located in the cooling tool (130) during the subsequent pressing cycle. [3] Method according to claim 2, where The fiber-reinforced plastic composite component (B') produced and pre-hardened in the press tool (120) is held in the tool part (122) attached to the intermediate plate (140) by means of vacuum suction when the intermediate plate (140) is swivelled (S).

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