WO2000067996A1

WO2000067996A1 - Press with a steel plate

Info

Publication number: WO2000067996A1
Application number: PCT/AT2000/000114
Authority: WO
Inventors: Karl Narbeshuber
Original assignee: Berndorf Band Gesmbh
Priority date: 1999-05-07
Filing date: 2000-05-03
Publication date: 2000-11-16
Also published as: AU4274900A; ATA82799A; AT413679B

Abstract

The invention relates to a press, comprising a steel plate (4, 5) with a thickness (d1) of between 1.0 mm and 3.0 mm and a surface roughness of between 1.0 νm and 4.0 νm and comprising a heating device (13, 14). Said heating device introduces heat into the plastic materials using a working plane of the steel plate (4, 5). The plate has a single-layer or multi-layer, butt-welded welding joint (17), whereby the surface (20) of said welding joint (21) is located in a concave surface which is located at a maximum normal distance, in particular, between 30 νm and 50 νm from the working plane (18) of the steel plate (4, 5). A surface intersection curve of the welding joint (17) and the adjacent areas of the working plane which lie on either side, is continuous with a normal plane, in relation to the working plane (18) of the steel plate (4, 5). The surface (20) of the welding joint (17) which is on the opposite side of the steel plate to the working surface, lies in a surface which is located at a maximum distance of 20 νm from the plane (19) of the steel plate. The welding joint (17) has a minimum thickness (d2) which is at least 50 νm lower than the (d1) of the steel plate.

Description

Press with a sheet

The invention has a press with a sheet of steel, e.g. B. press plate, in particular endless belt, and a sheet for a press to the subject.

Various devices are known for the production of essentially plane-parallel plates with a smooth surface from plastic materials. In the case of stack presses, loosely preformed plates are used, a layer of the masses of the product to be produced being in each case arranged between an upper and lower punch, followed by a press plate, then a layer of the masses of the product to be produced, etc. These plastic masses are then solidified by the action of heat and pressure. The production takes place discontinuously.

In a further device for producing chipboard, plastic films or the like, the masses to be thermally solidified are introduced into the gap between endless belts of a double belt press. Such tapes have z. B. a width of 2.0 m and a length of 14.0 m. The uniform movement of the upper and lower belt is 10 m / min. The heat is introduced from both the lower and upper belt via heat conduction on and through the upper and lower belt. At least one of the tapes has a smooth surface with an average roughness of a few μm, whereas the other tape can have a structure with which a surface is embossed and solidified during the pressing process.

Press plates have a particularly high surface quality, with particularly high demands being placed on both the flatness and the roughness. During the Production can result in damage to the press plates due to inhomogeneities in the pressed material. Such inhomogeneities are, for example, due to metallic inclusions in the woods. Conditional product accumulations and the like. As a result, the press plates, which have a relatively small thickness, begin with 1 mm

2 mm, locally deformed. However, these local deformations are difficult to align, so that it is necessary to replace the corresponding sheet metal area. Such an exchange can be done either by exchanging a sheet metal strip that extends over the entire width of the

Sheet extends or by replacing a round area. According to EP-A-0 820 833, a corresponding area is removed mechanically or by plasma cutters from the sheet. This removal is carried out by guiding the plasma cutter or a mechanical cutting device along a guide held on the sheet metal via electromagnets or vacuum suction elements which are connected to a vacuum source. After removing a round blank from the sheet, the cut surfaces in the sheet are machined, the processing tool, a milling cutter, being moved again along the guide fastened to the tape by an electric motor. The machining chips or the like are collected in a cup which is arranged below the endless belt. Then a round blank to be welded in is inserted, which is again fixed in the desired position by means of a holder. Then a welding device, u. between a TIG welding machine, moved The weld seam obtained in this way can be mechanically, e.g. B are reworked by cold forming. Such weld seams were produced in such a way that they have a substantial projection over the adjacent unaffected steel strip surface, so that in the subsequent machining process the weld seam and the weld surface are as uniform as possible subsequent areas has been reached, but the burn-in must be removed. B. with an angle grinder.

The aim of the present invention is to provide a sheet and a press with sheet metal in which plastic masses are subjected to heat, whereby weld seams, which are caused, for example, by the exchange of damaged areas of the sheet, do not cause any visually discernible inhomogeneities in the product produced.

The press according to the invention with a sheet of steel, for. B. press plate, in particular endless belt, in particular with a thickness of 1.0 mm to 3.0 mm and an average surface roughness of 1.0 microns to 4.0 microns for thermal shaping and

Solidification of plastic masses, e.g. B. for chipboard, plastic films and a heater that introduces heat into the plastic masses over a working level of the sheet, which is a single-layer or multi-layer butt-welded weld made of the same material, especially identer

Composition, comprising steel, consists essentially in that the surface of the weld lies in a curved surface which lies between the working plane and the plane of the sheet opposite this, which has a greatest normal distance, in particular from 30 microns to 50 microns

Working plane of the sheet, and a cutting curve of the surface of the weld seam and the areas of the work surface adjoining on both sides with a normal plane to the work plane of the sheet is continuous, and the surface of the weld seam on the side of the sheet metal opposite the work surface in one

Surface that is a maximum of 20 microns away from the surface, in particular in the plane of the surface of the sheet. It was quite surprising that a work surface which shows such an irregularity as the weld seam which is reduced compared to the rest of the surface does not lead to optical inhomogeneities in the product produced. This may be due to the fact that the inhomogeneity points that have previously occurred in weld seams are due to a lack of heat conduction from the steel sheet into the product. The formation of the weld seam on the one hand ensures that there are no notches on the working surface of the strip, as a result of which the service life of the sheet can be significantly increased and, on the other hand, the area of the weld seam as such can be kept particularly small since the edge regions are only melted to a lesser extent have to. Due to the specific design of the weld seam on the opposite side of the work surface

Surface of the press plate or strip is achieved so that the heat transfer from the heating devices in the press to the strip or press plate can be approximately the same as outside the weld.

If the surface of the weld seam and the adjoining areas forms an angle α of a maximum of 4 ', in particular a maximum of 2', with the working plane, on the one hand, particularly little mechanical processing of the weld seam and the adjoining areas can take place, the product in its optical appearance not is impaired.

If the weld seam is self-contained, a substitution of small areas of the sheet can also take place, and here too an optical impairment of the product produced can be avoided.

If the width of the weld seam with the areas adjoining on both sides, which lie in the curved surface, 40 to 70 times, in particular 50 to 60 times, the thickness of the sheet, there is a particularly good course of the transition between the weld seam and the working plane of the sheet, and furthermore the processing areas are kept relatively small.

If the weld seam is double V-shaped in cross-section, a particularly good heat transfer between sheet metal and heat-transferring units can be ensured, and a particularly high strength is also guaranteed.

If the intersection curve of the surface of the weld seam and the areas adjoining on both sides on the plane opposite the working plane with a normal plane points to the working plane at least one point of discontinuity to each

Side of the weld seam, a particularly high level of flatness of the weld seam can be achieved on the plane opposite the working plane, the two discontinuities surprisingly not affecting the product to be produced, but on the other hand make it possible for the

Processing of the weld seam and the adjacent areas can be kept particularly low, so that a particularly flat training can be achieved.

The steel sheet according to the invention, for. B. press plate, in particular endless belt, with a thickness of 1.0 mm to 3.0 mm and an average roughness of 1.0 microns to 4.0 microns and two plane-parallel planes, one of which serves as a working plane, with a weld made of the same type of material, in particular an identical composition, to steel, consists essentially in the fact that the surface of the weld seam lies in a curved surface, which is arranged in particular between the working plane and the plane of the sheet metal lying opposite it, which in particular has a maximum normal distance of 30 μm to 50 μm to the working plane of the sheet and a cutting curve of the surface of the weld seam with the areas of the working plane adjoining on both sides with a normal plane to the working plane of the sheet is continuous and the surface of the weld seam on the side of the sheet opposite the working plane in the plane or a surface whose highest maximum normal distance of at most 20 μm lies or has with the plane of the surface of the sheet lying opposite the working plane, and the weld seam has a minimum thickness that is at least 50 μm less than the thickness of the sheet. With a sheet of this type it can be achieved that products to be molded on this surface give an optically homogeneous impression, with weld seams which are required for different reasons not disturbing in the overall optical impression of the product to be produced

Product. However, the surface of the sheet has an optical inhomogeneity, and it was surprising that a homogeneous product can be achieved by creating an inhomogeneity area on the surface of the strip.

If the surface of the weld seam and the adjoining areas with the working plane form an angle α of at most 4 angular minutes, in particular 2 angular minutes, there is an optical inhomogeneity on the sheet itself due to the different reflection angles of the optical beams, but the product produced no inhomogeneity point recognizable, even with photographic reproductions.

If the weld seam is self-contained, smaller inhomogeneity areas can also be exchanged, with no optical centering on the substituted area in the Product takes place, but there is an optical adaptation to the subsequent areas.

If the width of the weld seam with the regions adjoining on both sides, which lie in the curved surface, is 40 to 70 times, in particular 50 to 60 times, the thickness of the sheet, then a particularly advantageous adaptation of the surface of the Given weld seam and the subsequent areas taking into account the total thickness of the weld seam, so that both the strength and the formation of the

Work surface taking into account the heat transfer with regard to the optically particularly homogeneous formation of the sheets is taken into account.

If the weld seam is double V-shaped in cross section, there is a particularly homogeneous transition along the entire thickness of the sheet between the weld seam and the sheet metal, the overall width of the weld seam being able to be kept smaller due to the double-sided welding.

If the intersection curve of the surface of the weld seam and the regions adjoining it on both sides on the plane opposite the working plane with a normal plane on the working plane has at least one point of discontinuity on each side of the weld seam, then a particularly flat one can be used

Formation of the side of the weld seam opposite the work surface, it was quite surprising that the two discontinuities with regard to the heat conduction of the sheet on the working level have no undesirable effects and the discontinuities also have no negative impact on the life of an endless strip. The invention is explained in more detail below with reference to the drawing.

Show it:

1 shows a double belt press in a schematic representation,

Fig. 2 shows the section through a sheet of steel with a weld.

The double belt press shown in FIG. 1 has a frame 1 which carries the entire device, in particular the deflection rollers 2 and drive rollers 3. The longitudinal distance between the axes a of the rollers is 720 mm. Through these roles a lower band 4 and an upper band 5 with a

Width of 1,950 mm made of highly polished steel moved in the direction of arrow v at the same speed. A gap 6 is formed by the two deflection rollers 2 with a diameter of 1,800 mm and the upper and lower belts 4, 5 cooperating with them, which gap is located only in the region of the deflection rollers, into which a preliminary product 7 made of plastically formable materials is introduced . The exact distance of the deflection rollers 2 is regulated by hydraulic rams 8, which sets a distance between the upper support 9 via the deflection rollers 2 and the lower support 10 for the lower deflection rollers 2. As seen in the direction of movement of the belts, there are upper and lower idlers 11, 12 which support the belts 4, 5 after the inlet gap. The drive rollers 3 each have their own drive motor 3a and 3b. The idlers have a common drive 15, which carries out a synchronous movement of this concern. In the linkage 16 of the common drive 15 Hardy disks, not shown, are provided to slight unevenness of the linkage, u. to compensate for each other between the waves. If necessary, other joints, such as universal joints, can be used. The upper rollers 11 and the lower rollers 12, which can be designed to be displaceable in the horizontal and vertical, have the task of supporting the upper or lower lower band and, if necessary, of keeping them slightly aligned in the direction of the other band. Through the upper heating device 13 and the lower heating device 14, heat is introduced to the upper belt 5 and the lower belt 4 by direct contact via grinding elements.

The endless belt 4 shown in section in FIG. 2 has a thickness d _! of 2.6 mm, the average roughness determined according to DIN M 1115 is 1.5 μm. The weld seam 17 is double V-shaped and has a thickness d of 2.550 mm. The belt 4 has an upper working level 18 and a level 19 opposite this. The cut surfaces of both the strip 4 and the weld seam 17 lie in a normal plane on the working plane 18. The surface 20 lies in a curved surface 21 which has a greatest normal distance x of 50 μm from the working plane 18 and can also be designed asymmetrically . The surface 20 of the weld seam 17 and the two adjoining regions 22 and 23 have a maximum angle α, which is enclosed by the curved surface 21 with the working plane 18, of 2 angular minutes. The curved surface 21 extends over 150 mm and is therefore 58 times the thickness di of the sheet. The curved surface 21 is continuous in section and merges continuously into the working plane 18, the angle α being continuously decreasing.

On the underside of the sheet is another level 19, the surface 24 of the weld coming to lie in level 19. The surface 24 can have a maximum distance from the plane 19 of 20 μm. Notched on both sides of the weld places 25 and 26 are provided, the discontinuities are on average.

The procedure for inserting a sheet blank into the endless band is as follows.

The point of inhomogeneity in the strip is determined and a hole is provided through the strip in the center thereof. A centering pin is guided through this hole, via which a guide with electromagnets is arranged on the belt. On the other hand, a cup is arranged on the centering pin. A plasma cutter with an electrical voltage of 380 V, compressed air at 5.5 bar and a speed of 2 m / min is guided along the guide. After a sheet-metal blank with a diameter of 300 mm has been cut out and removed, the cut edge is milled, the cut being essentially normal to the plane of the strip. A sheet blank was then inserted with a cutting edge that is normal to the working plane, the outer dimensions of which match the cut opening, a holder made of copper being provided underneath both the sheet and the sheet blank. The sheet round was also held in place by an electromagnet. Using a TIG torch, electrical voltage 220 V and 7 liters of argon per minute was obtained by melting the sheet and the

A blank weld is placed on the sheet blank, the sheet blank being tacked into the sheet before the actual welding process. The welding process is carried out at a speed of 140 mm / min on one side, whereupon the guide is positioned on the other side and on again

Welding process as described, but with a smaller depth. After completion of the welding process, cold forming was carried out by hammering, which was followed on the side of the working level and on the opposite level Weld seam with a grinding wheel, which was operated pneumatically and had a rubber plate with a diameter of 75 mm and was first processed or polished with grinding wheels K 80, K 120 and then with a fleece. The grinding and polishing was accompanied by a measuring process so that the configuration shown in FIG. 2 could be maintained. Cold forming enabled the weld seam and the adjacent areas on the side opposite the working level to be placed in the plane of the sheet. The total thickness was 2.550 mm. Automatic production is also possible.

Another circular blank was also welded in with a TIG welding machine, whereby the parameters listed above were adhered to and a welding wire with an identical composition to the sheet was used. The machining of the weld seam was carried out as above.

With an endless band, which had three welded round blanks with a diameter of 300 mm, two of which were designed according to the invention and a further round with 300 mm, in which the weld seam had the thickness of the sheet, whereas the two penetration areas on both sides of the weld seam were machined with an angle grinder, so that on both sides of the weld approximately annular troughs with a depth of

50 microns were present, and the weld seam was also cold worked so that the root of the same came to lie in the plane of the sheet, a medium-density fibreboard with 9 mm was continuously produced. Markings on the tape made it possible to determine whether with the corresponding

Area of the band with rounds welded in accordance with the invention or with a round plate which was not welded in according to the invention, the relevant area of a plate was produced. Three plate patterns were then uncut but also how known per se, after a grinding process under a light incidence of 30 °, subjected to optical inspection by seven people, annular discoloration of all of the people being able to be observed in the fiberboard produced with a round blank which was not welded in according to the invention, whereas the fiberboard produced with welded in according to the invention Discs could not be discolored by any person.

Claims:

Claims

Patent claims:

1. Press with a sheet of steel (4, 5), for. B. press plate, in particular endless belt, with a thickness (di) of 1.0 mm to 3.0 mm and an average surface roughness of

1.0 μm to 4.0 μm for thermal shaping and solidification of plastic masses (7), e.g. B. for chipboard, plastic films, and a heating device (13, 14), which initiates heat over a working level of the sheet (4, 5) into the plastic masses, which is a single-layer or multi-layer butt-welded weld (17) made of the same material, in particular Identical composition to the steel, characterized in that the surface (20) of the weld seam (17) lies in a curved surface (21), which lies in particular between the working plane (18) and the plane (19) of the sheet metal lying opposite this, which has a greatest normal distance, in particular from 30 μm to 50 μm, to the working plane (18) of the sheet (4, 5), and a cutting curve of the surface of the weld seam (17) and the areas of the weld seam adjoining on both sides

Working plane with a normal plane to the working plane (18) of the sheet (4, 5) is continuous, and the surface (20) of the weld seam (17) on the side of the sheet opposite the working surface lies in an area which is at most 20 μm away from the plane (19), in particular in the plane (19), of the sheet and the weld seam (17) has a minimum thickness (d ₂ ) which is at least 50 μm less than that (di) of the sheet.

2. Press with a sheet according to claim 1, characterized in that the surface (20) of the weld seam (17) and the adjoining areas (22, 23) with the working plane an angle (α) of at most 4 angular minutes, in particular of at most 2 Include minutes of angle.

3. Press with a sheet according to claim 1 or 2, characterized in that the weld seam (17) is self-contained.

4. Press with a sheet according to one of claims 1, 2 or

3, characterized in that the width of the weld seam (17) with the adjoining on both sides, which are lowered relative to the working plane (18), is 40 to 70 times, in particular 50 to 60 times, the thickness (di) of the sheet is.

5. Press with a sheet according to one of claims 1 to 4, characterized in that the weld seam (17) is double V-shaped in cross section.

6. Press with a sheet according to one of claims 1 to 5, characterized in that the cutting curve of the surface (20) of the weld seam (17) and the areas adjoining on both sides of it on the side opposite the working plane (18) with a normal plane on the sheet (4,

5) has at least two discontinuities (25, 26).

7. Steel sheet, e.g. B. pressed sheet, in particular endless belt with a thickness between 1.0 mm and 3.0 mm, an average roughness of 1.0 μm to 4.0 μm and two plane-parallel planes, one of which serves as a working plane, the one Has a weld seam of the same type, in particular an identical composition to the steel, characterized in that the surface (20) of the weld seam (17) lies in a curved surface (21), which is in particular between the working plane (18) and the plane (19 ) of the sheet, which has a greatest normal distance, in particular from 30 μm to 50 μm, to the working plane (18) of the sheet (4, 5), and a cutting curve the upper flat of the weld seam (17) and the areas of the work surface adjoining on both sides with a normal plane to the work plane (18) of the sheet (4, 5) is continuous, and the surface (20) of the weld seam (17) on the opposite side of the work surface Side of the sheet lies in a surface that is at most 20 μm away from the plane (19), in particular in the plane (19), of the sheet and the weld seam (17) has a minimum thickness (d ₂ ) that is at least 50 μm less than that of the sheet

Steel sheet according to claim 7, characterized in that the surface of the weld seam (17) and the adjoining areas (22, 23) form an angle (α) of at most 4 angular minutes, in particular at most 2 angular minutes, with the plane of the working plane.

Steel sheet according to claim 7 or 8, characterized in that the width of the weld seam (17) with the regions (22, 23) adjoining on both sides, which lie in the curved surface (21), is 40 to 70 times, in particular 50 to 60 times the thickness of the sheet

Steel sheet according to one of claims 7, 8 or 9, characterized in that the weld seam (17) is double V-shaped in cross section

Sheet steel made according to one of claims 7 to 10, characterized in that the intersection curve of the surface (20) of the weld seam (17) and the areas adjoining it on both sides on the plane opposite the working plane (18) with a normal plane on the working plane has at least one point of discontinuity (25, 26) on each side of the weld seam (17)