The invention relates to a method for producing a component from a fiber composite material.
DE 102 53 300 A1 discloses a process for producing structural components with a plastic matrix material that is reinforced by glass fibers, wherein intentionally aligned carbon fibers are at least partially provided according to load paths of the component in the loaded state. In particular, the aligned carbon fibers are embedded between two layers of substantially randomly oriented fiberglass structures.
EP 0 491 353 A1 discloses a method, wherein load-path-oriented fiber portions are applied by pressing locally with a pressure roller while also locally heating the fiber tape. This method has the disadvantage that several fiber orientations cannot be applied at the same time. In addition, this method limits the geometric complexity of components.
DE 10 2006 025 280 A1 discloses a method for producing a fiber-reinforced component, wherein a bundle of a continuous fiber is impregnated and this fiber/matrix strand is placed with almost the final contour in a temperature-controlled device over a nozzle by a handling device and thereafter consolidated. In particular, the fiber/matrix strand with the continuous fiber is placed in the mold and in other areas a fiber/matrix strand with long or short fibers.
Fiber composite materials are produced by labor-intensive and cost-intensive processes, wherein the fiber composite material consists of a proportion of fibers and a proportion of a matrix. When processing continuous fiber-reinforced thermoplastics, it is therefore customary to reshape flat intermediate products which already contain a sufficient proportion of thermoplastic matrix in the fiber material. This blank is referred to in particular as a board, wherein the starting material of the board is preferably an organic sheet. For example, an organic sheet is done produced, inter alia, by layering flat semi-finished fiber products which are pressed together with thermoplastic materials in film and/or powder form by applying pressure and temperature
In particular, all forms of thermoplastic materials can be used as a matrix material of the organic sheet. Typical representatives are polyamides, polypropylenes, polyethylene terephthalates, polyether ether ketones, polyphthalamides and thermoplastic polyurethanes.
In particular, an intermediate product, which preferably comprises the fiber material and a thermoplastic matrix material, is referred to as a preform, which passes through the processing conditions or processing states of a semi-finished fiber product from merging all continuous fiber fractions and their matrix components. A preform preferably passes through the processing conditions or processing states at the continuous fiber portion until it is fully formed.
It is customary for an economical production of the starting material of the boards to produce, in a first step, a large-area fiber material in form of a sheet product, from which the board is then cut out. As part of the manufacturing step of this sheet product, a tensile stress on the fiber material is necessary for process control which requires a continuous fiber across the width of the sheet product. The board is thereby limited to a fiber architecture that is constant over the entire surface.
Fibers have enhanced mechanical properties in their longitudinal direction. Therefore, in the mechanical design of the fiber material in the component, the alignment of the continuous fiber material is oriented on and along the load paths of the product. Components can have areas of higher load, with respect to which the wall thickness, the fiber structure and the fiber path are designed. This causes oversized wall thicknesses in the continuous fiber material in surrounding areas of the stress peak, which cannot be avoided due to the way the circuit board is manufactured. However, the cost structure of products of this material class requires economical use of the base material (organic sheet). This leads to a conflict between objectives of economy and mechanical properties of the continuous fiber material.
Methods are known which provide for a direct layering of the endless fiber material on planar or three-dimensional backing-layers, which are subsequently shaped such that the fiber material is disposed in the load path. These methods can be distinguished as methods for processing unconsolidated (dry) fibers and methods for processing consolidated fibers (fibers provided with a matrix). Processes of dry-layering (e.g. TFP: Tailored Fiber Placement) stitch reinforcing fibers with a sewing thread onto a carrier material which are, in the course of further processing, impregnated with a chemically/thermally curing resin and fixed to form a component. The process parameters used for impregnation, such as pressure and temperature, however, lead to an increase in equipment costs.
Processes for load-path-oriented processing of thermos-plastically consolidated semi-finished products are based either on an intimate material connection of the reinforcing fibers to a carrier or on a preliminary fixation of the fiber with subsequent consolidation in a subsequent method step. Among other things, thin tapes can be deposited along paths of the component geometry to be traveled. In this type of process, the geometric complexity is limited by the radii of the continuous fibers that can be deposited and the dimension of the depositing facilities.
If, however, fiber tapes made of continuous fiber reinforcement are laid down along paths on three-dimensional geometries over the length of a component, differences in length between the inside of the curve and the outside of the curve limit the radii that can be deposited error-free and consequently also limit the geometric component complexity.
The application of reinforcing fibers to increase the anisotropy of continuous fiber products is thus known. The known methods have the particular disadvantage that either an intermediate product is created before heating, which results in at least one additional method step and a deterioration of the material properties, or that the reinforcing fiber components are sequentially deposited onto the substrate as a pattern, which also requires an additional method step and reduces the speed of the production line. Furthermore, the use of hot melt adhesives is known, which however leads to a material-inhomogeneous fiber matrix.
On this basis, it is therefore the object of the invention to provide a simpler method for producing a component from a fiber composite material.