DE102007018921A1 - Method for stocking flat, sheet-like semi-finished products and supply reel for flat, sheet-shaped semi-finished products - Google Patents

Abstract

The method involves coiling a flat, sheet-like semi-finished product around a take-off reel (10) with roll cores (12) symmetric to semi-major axes of different dimension, where the axes are perpendicular to each other and are non-circular in cross-section. The reel is aligned after the coiling of the semi-finished product on the cores and before winding up of the product, where larger of the major axes run parallel to horizontals. The reel is arranged with the product in a bearing and/or transport cradle.

Description

The The invention relates to a method for storing planar, sheet-like semi-finished products, in particular of fiber-matrix semi-finished products with thermosetting or thermoplastic matrix. The invention is further on a supply reel for flat, sheet-shaped semi-finished product, in particular for fiber-matrix semi-finished products directed with thermosetting or thermoplastic matrix, the for carrying out the invention Method is suitable.

extensive Fiber-matrix semi-finished products are semi-finished products made from reinforcing fibers, mainly glass fibers or carbon fibers, which are impregnated with a plastic matrix. At the matrix it may be a thermoset or thermoplastic act. Become a fiber-matrix semi-finished products with thermosetting matrix often referred to as SMC (Sheet Molding Compound). Fiber-matrix semifinished with thermoplastic matrix there are in particular as LFT (long fiber reinforced Thermoplastics) and as GMT (glass mat reinforced thermoplastics) The fiber-matrix semi-finished products are mostly used in automated manufacturing processes used for the production of fiber-plastic composite components. For example, semifinished products with thermoplastic are used Matrix for door panels or luggage compartment covers for motor vehicles od. Like., While SMC for the production of automotive exterior parts such. B. trim parts used by truck tractors. The flat semi-finished products, where the reinforcing fibers mostly as chopped fibers present, but can also occur in mat or in tissue form, can be cut and finished by extrusion Processing components. It can thereby be particularly economical Body parts for cars, sports equipment and also Components manufactured for the aerospace industry where it is also possible, while pressing another Insert fasteners in the mold and during manufacture of the component to be firmly connected to the fiber composite material.

at the production of such semi-finished products becomes Material produced in long webs usually on a carrier film made of polyamide or polyethylene and then either in boxes folded or wound on a reel. At the moment in general used supply reels these have a hub with a Diameter of usually 250 mm, on which then one Web length wound up with a total weight of about 350 kg becomes. Such, each 300 to 350 kg of semi-finished bearing reels are delivered to the material processing producer, usually in a supply and transport shelf, the four such roles can take up where then the semi-finished from the supply reel and the backing sheet is peeled off before a section the required length of the semifinished product in a press od. Like. Formed and cured to the finished product becomes. Once the material wound on a roll is complete is consumed, the supply reels at the producer and processors of the material to be changed, causing a disruption of production forces. For example, suppose that for each component to be produced from the semifinished product has a quantity of 20 kg and the cycle time for each component four minutes, this requires a change of with about 300 kg of wound reels after only one hour.

at Arrangement of the semifinished product in boxes in which the semifinished product zigzag is arranged in a variety of layers, although more material be stored and transported per packaging unit, namely up to about 1,000 kg, but this approach has the disadvantage that the material is heavily deformed at the kinks and also tends to dry out there, so that mistakes occur in the finished components, if not the areas around the fold lines are cut off before processing the semifinished product and disposed of unused. This not only leads to a high material loss, but limits the maximum size the components to be produced from the semifinished product.

From the EP 1 038 814 A2 is a winding system for sheets of thermoset compound compounds known to be used in the transport rollers for fiber-matrix semi-finished products, which have a width of 1.50 m and a diameter of the winding core of 400 to 600 mm. Due to the larger hub can be wound on such transport rollers also more web-shaped fiber-matrix semi-finished than in the hitherto most used 350 kg rollers. The mass and size ratios in such large rolls are the same as in the standard rolls, ie, the amount of wound onto the winding core larger diameter web material is directly proportional to the volume of the winding core. While standard rolls with a core diameter of 250 mm can be wound up to 350 kg SMC, a large roll with a core diameter of 550 mm, ie a 4.84 times as large volume of the winding core, can store 1.694 kg. In this bearing principle, in which a large amount of SMC is wound on a winding core with a circular cross-section, there is a risk that flows due to the high weight and the resulting surface pressures, especially on the wound close to the core parts of the web flow of the plastic matrix and the from the reel unwound semi-finished product then does not have more over its entire length constant area weight more.

task The invention is a process and an implementation thereof to provide a particularly suitable supply reel, whereby a larger Quantity of sheet-shaped semi-finished product than in the previous mainly used standard containers can be stored without this under the basis weight constancy of the wound on the reel Material suffers.

These Task is with the inventive method solved by the fact that the flat, web-shaped Semi-finished product on a supply reel with a non-round cross section, to two mutually perpendicular half-axes of different sizes symmetrical winding core is wound up and that the Supply reel after winding the semifinished product on the winding core and substantially aligned prior to unwinding the semifinished product is that the larger of the two half-axes at least approximately parallel to the horizontal. Accordingly, the inventive Supply reel, characterized in that the winding core the reel a non-circular, to two mutually perpendicular half-axes different size symmetrical cross-section having. The winding core can, for example, a substantially have elliptical or oval cross-section. The size ratio the larger half-axis to the smaller half-axis is preferably in the range of 1.25 to 3, in particular in the range between 1.35 and 2.75. For example, it is possible that the larger half-axis is a length between 225 and 325 mm and the smaller half-axis has a length between 125 and 220 mm.

Of the Winding core can also be a roughly diamond-shaped, in the Corner areas have rounded and / or flattened cross section, wherein the cross section of the winding core in the apex areas of the larger half-axes preferably approximately circular segment-shaped rounded and in the apex areas of the smaller half-axes advantageously with approximately parallel to the larger ones Semi-axis extending flattening is provided under formation of radii or circular arcs in the adjacent sides of the go over diamond-shaped basic shape. Such Design can be, for example, with each other simply produce welded steel segments.

A Supply reel according to the invention can with the on the winding core wound semi-finished in a storage and / or transport rack be arranged and fixed in it against rotation. In the inventive Storage of the semifinished product on the winding core with non-circular, in particular oval or elliptical cross-section becomes a larger Proportion of the weight of the wound web directly into the winding core removed, so that the absorbed by the material itself tensile forces be reduced and also the pressure loads that the material is less than a supply reel with cylindrical Winding core on which the same amount of semifinished product is wound up.

At the Winding and unwinding of the material on the or the invention (s) Supply reel with non-round in cross section winding core is the winding speed at constant rotational speed of the reel not constant. Around To counter this, it is possible to use the supply reel Winding and / or unwinding of the semifinished product on or from to drive the winding core with variable rotational speed. Indeed but it has been shown that such an approach in most cases is not necessary, because that Winding and unwinding of the material also takes place at a constant drive speed for the reel with great reliability and quality.

Further Features and advantages of the invention will become apparent from the following Description and the drawing, wherein preferred embodiments the invention are explained in more detail by way of examples. It shows:

1 a first embodiment of the supply reel according to the invention for use in the inventive method in perspective view;

2 the object of 1 in a cross section through the winding core of the supply reel;

3 a highly schematic comparison of a supply reel with a round winding core compared to a supply reel according to the invention comparable capacity;

4 a second embodiment of the supply reel according to the invention in one 2 corresponding representation; and

5 the winding core of the supply reel according to the second embodiment according to 4 in a ge compared to this enlarged view in front view.

Denoted in the drawings 10 a supply reel for winding and storing a flat, sheet-shaped semi-finished product 11 namely, a thermosetting matrix fiber matrix strip (not shown) on a carrier film (not shown), as it is also known under the name "SMC" (Sheet Molding Compound).

The supply reel consists essentially of a central winding core 12 , which at its two front ends with thrust washers 13 is provided which prevent damage to the edges of the wound on the winding core semifinished product. The thrust washers are provided on the outside with hexagonal end plates, which allow not only in a particularly simple manner a correct Oriendierung the hub relative to the horizontal, for example, during transport and storage of the reel, but also a space-saving stacking.

How best from the 2 to 5 can be seen, the winding core has a non-circular cross-section, where it leads to two mutually perpendicular half-axes 14 . 15 different size is configured symmetrically. In the in the 4 and 5 illustrated embodiment, the winding core 12 an elliptical cross section, wherein the size ratio of the larger semi-axis 14 to the smaller half-axis 15 is about 1.4. The length L of the larger half-axis 14 is in the illustrated embodiments about 275 mm, the length l of the smaller half-axis 15 is about 200 mm. In the in the 1 and 2 illustrated embodiment is the cross-sectional shape of the winding core 12 Derived from a rhombus that is used for illustration in 2 shown in dashed lines and with 16 is designated. Starting from this basic form of a rhombus is the winding core in its the large half-axes 14 cutting corner areas 17 rounded with a comparatively large radius and in the small semi-axes 15 cutting vertex areas 18 with parallel to the larger half-axis 14 extending flattenings 19 provided to form Radii 20 in the neighboring pages 21 the diamond-shaped basic shape 16 pass.

The semifinished product wound on the supply reel according to the invention with a non-circular winding core in cross-section 11 has even after a long storage period of several days one opposite a winding core with a circular cross-section (left in 3 ) remarkably high basis weight constancy, when the storage according to the method according to the invention is carried out so that the semifinished supply reel is aligned so that the larger of the two semi-axes 14 essentially parallel to the horizontal 22 runs like this in 3 is shown. In a first attempt to test the performance of the oval / elliptical core, about 2,000 kg of a fiber-matrix semi-finished product (SMC) under the trade name HUP MSF 227-9010 (32287) was produced, of which 1,891 kg were in the 1 and 2 wound core were wound up. The supply reel was then stored according to the invention for five days in an orientation in which the large half-axes ran parallel to the horizontal. The material was rewound after 5 days storage on conventional reels with a core diameter of 250 mm. The weight of the material on the standard reels was: Role 1: 364.5 kg Roll 2: 357 kg Roll 3: 370.5 kg Roll 4: 353 kg Roll 5: 371 kg

The from the heavy-duty reel according to the invention Material developed in an oval / elliptical winding core in one Amount of nearly 1,900 kg was checked for warping or deformation, while it was wrapped on the small rolls. None Distortions or deformations could be detected. The quality the material was comparable to that of standard rolls achieved with about 350 kg net weight regularly becomes.

The basis weight of the material unwound from the supply reel according to the invention was likewise determined at different positions of the winding core. For this purpose, 100 cm ² large test pieces were removed from the unwound semifinished product web. The basis weights determined therefrom and their deviation relative to the original basis weight of the material before being wound up on the supply reel according to the invention and storage over a period of five days are reproduced in Table 1. It can be seen that the deviations from the original weight, which are in the range of ± 50 g per m ² , represent an excellent value, especially considering that nearly 1,900 kg were on the supply reel according to the invention. Material Length / Percent Position relative to the winding core Basis weight / g / m ² Deviation / percent 0 top 4096 2.4 25 top 4036 0.9 50 top 3988 -0.3 50 bottom 3988 -0.3 75 top 3994 -0.2 75 bottom 3988 -0.3

comparable Values were also obtained upon storage of the material on the invention Supply reel over a comparatively long period of time of two weeks. Even in such a case could not discard and no deformation of the over two weeks stored material when rewinding to other (standard) reels. The deviations of the weight per unit area the initial value was between -2.2 and + 3.5%, with the Deviations essentially independent of the relative position of the examined material to the coil core were and in the face of a wound amount of 1,700 kg and the comparatively long Storage period are considered surprisingly low have to.

The Invention is not limited to the illustrated and described embodiments limited. In particular, other cross-sectional shapes are also the winding core conceivable, for example an oval cross section, in particular also those cross-sections in which the ratio the lengths of the larger semi-axis to smaller semi-major axis is still significantly larger than in the illustrated and described examples. It has shown that it is for winding the web-shaped Material on the supply reel according to the invention not absolutely necessary is the rotation speed of the reel to vary during one revolution to the changing one Winding radius to take into account. Such a variation of the rotational speed The reel can then make sense, if the sizes the two half-axes clearly different from each other to the then slightly greater risk of wrinkling when winding up to meet.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• - EP 1038814 A2 [0005]

Claims (12)

Method for storing flat, sheet-like semi-finished products, in particular of fiber-matrix semi-finished products with thermoset or thermoplastic matrix, characterized in that the flat, sheet-like semi-finished products ( 11 ) on a storage rasp ( 10 ) with a non-circular cross-section, to two mutually perpendicular half-axes ( 14 . 15 ) different size symmetrical winding core ( 12 ) is wound and that the supply reel ( 10 ) after winding up the semi-finished product ( 11 ) on the winding core ( 12 ) and before the unwinding of the semifinished product is substantially aligned so that the larger of the two semi-axes ( 14 ) at least approximately parallel to the horizontal ( 22 ) runs. Method according to claim 1, characterized in that the supply reel ( 10 ) with the on the winding core ( 12 ) wound semifinished product ( 11 ) is arranged in a storage and / or transport rack and fixed therein against rotation. A method according to claim 1 or 2, characterized in that after a partial unwinding or removal of the semifinished product ( 11 ) from the supply reel ( 10 ) this is stopped again in a position in which the larger of the two half axes ( 14 ) of the winding core ( 12 ) at least approximately parallel to the horizontal ( 22 ) is located. Method according to one of claims 1 to 3, characterized in that the supply reel ( 10 ) for winding and / or unwinding the semifinished product ( 11 ) on or from the winding core ( 12 ) is driven at variable rotational speed. Supply reel for flat, sheet-like semifinished product, in particular for fiber-matrix semifinished product with thermosetting or thermoplastic matrix, suitable for carrying out the method according to one of claims 1 to 4, with a winding core, characterized in that the winding core ( 12 ) a non-circular, to two mutually perpendicular half-axes ( 14 . 15 ) of different size has symmetrical cross-section. A supply reel according to claim 5, characterized in that the winding core ( 12 ) has a substantially elliptical or oval cross-section. A supply reel according to claim 5 or 6, characterized in that the size ratio of the larger semiaxis ( 14 ) to the smaller half-axis ( 15 ) is in the range between 1.25 and 3. A supply reel according to claim 7, characterized in that the size ratio of the larger semiaxis ( 14 ) to the smaller half-axis ( 15 ) ranges between 1.35 and 2.75. A supply reel according to one of Claims 5 to 8, characterized in that the larger semiaxis ( 14 ) has a length (L) between 225 and 325 mm and the smaller half-axis ( 15 ) has a length ( l ) between 125 and 220 mm. A supply reel according to one of claims 5 to 9, characterized in that the winding core ( 12 ) has an approximately diamond-shaped, rounded in the corners and / or flattened cross-section. A supply reel according to claim 10, characterized in that the cross section of the winding core ( 12 ) in the vertex areas ( 17 ) of the larger semiaxes ( 14 ) are rounded off in a circle-segment shape and in the vertex areas ( 18 ) of the smaller half-axes ( 15 ) with approximately parallel to the larger semiaxis ( 14 ) flattenings ( 19 ), which forms radii ( 20 ) or circular arcs in the neighboring sides ( 21 ) of the diamond-shaped basic shape ( 16 ) pass over. A supply reel according to one of claims 5 to 11, characterized in that the winding core ( 12 ) consists of welded steel segments.