DE4033230C2 - - Google Patents

Description

The invention relates to a method for applying Embossed engravings by applying laser beams to large format metal press plates and / or endless belts for surface treatment of sheets or plates made of plastic, wood or Press laminates for use in discontinuous or continuous working heating presses.

Metal embossing dies are used, for example, in the furniture industry for the surface structuring of plastic sheets made of PVC, Polyester, cork, chipboard coated with melamine films and Thermoset laminates used as structural pictures often wood pores, fine or coarse grain, pictorial representations, but also any other surface structures to have.

The structuring is usually done in hydraulic Multi-level heating presses using large-format die press plates or in known, continuously operating endless belt systems.

For the production of embossed structures in such press plates or endless belts one uses known technologies, such as described for example in DE-PS 27 06 947. In this well-known Procedure is on the endless steel belt or on the flat, large-sized sheet on one or both sides an etch-resistant Color using a suitable printing device, for example a rotary printing machine, a structure pattern printed, wherein after drying the caustic paint, the steel band or the Press plate is exposed to an acid etching treatment. In doing so the color-free areas are etched to a specified depth using the acid, so that after the etching process, in order to obtain superimposed Structures can be repeated several times, a desired one  Embossed engraving profile is created. After the end of the etching treatment the continuous steel strip or the press plate becomes a final one Polishing, matting and glossy treatment and possibly a subsequent one Hard chrome plating. Other manufacturing processes to form embossed engravings on the press plates or endless belts also use well-known reproduction photography or electroplating process.

These known embossing processes are relatively complex and rely on traditional techniques that invariably unite high manufacturing costs.

The invention is therefore based on the object for Manufacture of embossed engravings using modern manufacturing processes to make and a much higher manufacturing accuracy to achieve the structuring than was previously possible.

This is achieved according to the invention in that the press plate and / or the endless belt first with a full-surface carrier web made of plastic, an elastomer, or with a galvanic Metal layer coated or coated with an etch-resistant color film and that by means of the laser beams only one Thickness of the carrier web or the coating-detecting embossed structure is generated and then the bare metal Place the press plates and / or the endless belts of an etching treatment be subjected.

The proposal according to the invention ensures that only the full-surface carrier web or the full-surface coating is processed by means of the laser beam because the The intensity of the laser beam can be significantly lower than at the immediate processing of metal, which means at the same time that with higher intensity of the laser beam the processing times the press plates can be extremely reduced. Furthermore are in the invention, the areas not to be etched by  the remaining parts of the material are effectively protected. As an essential Another advantage is that the processing plates or tapes with a usual length of 7 up to 14 meters without repeat engravings.

From DE-OS 26 02 330, which is used to form the preamble of Claim 1 used as the closest prior art , it is known to have material from an area to be engraved to be removed by means of laser beams. The object to be engraved is a gravure cylinder. The engraving is done by direct Laser irradiation of the metal cylinder surface in one work step, while for the method according to the invention Embossing engraving is done in two steps, with the solution for the task is crucial that the press plate and / or the endless belt first with a full-surface carrier web Plastic or an elastomer or with a galvanic metal layer or is coated with a caustic color film and by means of the laser beams only the thickness of the carrier web or of the coating-detecting embossed structure is generated before the Tapes or plates are subjected to a subsequent etching treatment will.

With the proposal according to the invention, a solution was found for the first time specified with the press plates and / or endless belts with extreme large dimensions can be engraved without repeat.

From DE-PS 35 09 551 it is known to emboss a stamp Manufacture printing holograms by using a laser light illuminated object a main master as a transmission hologram is developed, and the reconstructed object then saved on film material and the film is then developed becomes. The film itself consists of a silver halide. EP-A 03 06 932 describes a high-pressure process To design a printing plate with printing areas made of plastic that reproductions that are as true to the original as possible are possible.  

The critical surface tension is intended to solve this problem of the ink-carrying, printing areas reach a certain value. The shape of these printing parts can be different also done by laser engraving. With the cited documents it is not known to take an embossed engraving in two steps according to the new labeling part of the main claim perform. In this respect, these two previous publications far from the registration status.

The manufacture is from Derwent abstracts number 31 73 8 Y / 18 an aluminum printing plate with a copper coating, Known silver and similar materials. The engraving is done also by a laser beam. From the DE prospectus "Laser automat" from the company Jens Scheel special machines 1/79 an automatic engraving machine for flexographic printing rollers and rubber printing blocks is known. Here, too, processing is carried out using laser beams. Out Chemical abstracts Volume 88 (1978) number 30 38 8 s Page 479, it is known to have an aluminum plate whose surface is coated is to engrave with a laser beam. From these publications it is known the printing areas of printing plates to be coated and then engraved with laser beams. The coating remains on the printed raised areas receive. The cited references do not describe whether only the coating is engraved. From the Writings only show that the coating is extremely thin should be. When printing with the high-pressure process, however, it is imperative necessary that the printing positive parts face project the negative parts by a relatively large amount, so that the printed and unprinted parts of the manufactured Print product are sharply separated and thus For example, in multicolor printing, the different colors Color zones are sharply separated from each other. As a result it is necessary that in the known printing plates not only the coating but in contrast to the invention the adjacent material parts are also removed.  

In summary, it can be said that with all responses by means of the printing plates, the stamps, the clichés or the Printing cylinder a typeface or a print image can be generated should. The typeface or print image can only be created if suitable ink is applied to the substrate. In contrast are those produced with the method according to the invention Press plates or endless belts for cold and / or hot forming of the objects to be embossed work directly onto the object without an additional medium. Process engineering is a printing process of whatever kind opposed to an embossing process.

Further advantages and expedient further developments of the invention Process flow result from the subclaims 2 to 7.

Different exemplary embodiments of the method according to the invention are explained in more detail below with reference to the accompanying drawings; show in the drawing:

Fig. 1 shows a partial cross section through a known hot press during the shaping,

Fig. 2 is a simplified side view of a hot press having endless belts during the structuring of a Preßlaminates,

Fig. 3 shows a revolving metallic endless belt with an upstream laser beam head and the computer while the laser beam action on the surface of the endless belt,

Fig. 4 is a schematic plan view of the device according to Fig. 3 during laser engraving treatment,

Fig. 5 is a partial end view of a device for engraving a flat metal press plate by means of laser beams and

Fig. 6 is a plan view of the device according to Fig. 5.

Figs. 1 and 2 show two ways of applying press plates prepared by the inventive process. Fig. 1 shows schematically a discontinuously operating known heating press, which essentially has an upper press frame 10 , a lower press frame 11 , an upper pressure and heating plate 13 , on the mutually facing sides of the pressure and heating plates 12 , 13 , provided with embossed engravings Press plates 14 , 15 , between which a plate 16 to be structured lies and a hydraulic pressure lifter 17 which acts on the lower pressure and heating plate 13 .

Fig. 2 shows a continuously operating hot press comprising two endless, externally provided with the embossing engraved steel strips 18, 19 comprises. The mutually facing strands of the steel strips 18 , 19 are pressed against the plate 16 to be structured by two pressure transmitters 20 , 21 . The steel strips 18, 19 run around four arranged axially parallel drums 20, 21, 22, 23, wherein the two a respective steel strip 18 and 19 respectively associated drum pairs 20, 21 and 22, 23 arranged to each other side in the same axial distance.

FIGS. 3 and 4 show the production of the emboss gravure to one of the two in the continuous hot press shown in Fig. 2 steel belts used 18 or 19. This device is equipped with two axially parallel cylinders 25 , 26 , over which a respective steel strip 18 or 19 is placed. The center distance of the cylinders 25 , 26 depends on the length of the steel strip 18 or 19 . The device is also equipped with a laser beam head 27 , which belongs to the prior art and is therefore not described in detail. The laser beam head 27 can be moved along a guide path consisting of two guide rails 28 , running parallel and at a distance from the axis of rotation of the associated cylinder 25 . The movements of the steel strip 18 or 19 and the laser beam head 27 are controlled by a computer 30 . Likewise, the intensity of the beams 27 ' generated by the laser beam head 27 ' can be controlled by the computer 30 .

The embossed engraving is made using two different working methods. FIGS. 3 and 4, the steel strip 18 or 19 rotates. This can be done gradually, at a constant or changing speed. The laser beam head 27 stands still during one revolution of the steel strip 18 or 19 . Then it is moved one step further. The embossing is consequently carried out line by line from one longitudinal edge of the steel strip 18 or 19 to the other, ie parallel to the longitudinal edges. The area that has already been engraved is identified in FIG. 4 by the double-layered area. In the device according to FIGS. 3 and 4, however, the laser beam head 27 can alternatively also be moved stepwise, at constant or changing speed, transversely to the longitudinal edges of the steel strip along the guide 28 when the steel strip 18 or 19 is stationary. When the laser beam head 27 has reached a long side of the steel strip, the steel strip 18 or 19 is advanced by one line. The engraved lines then run transversely to the longitudinal edges of the steel strip 18 or 19 .

FIGS. 5 and 6 show the production of the emboss engraving of a press plate 14 or 15 for the hot press according to Fig. 1. The press plate 14 or 15 rests on a horizontal table 29. The laser beam head 27 is mounted on a traverse 31 running transverse to the longitudinal edges of the press plate 14 or 15 and can be moved in a controlled manner by the computer 30 . At the front ends of the crossmember 31 there are rollers 32 so that the crossmember 31 can be moved along guide rails 33 which run along and parallel to the longitudinal edges of the press plate 14 or 15 . The movement of the laser beam head 27 from a longitudinal edge of the press plate 14 or 15 is advantageous since the length of the press plate 14 or 15 is substantially greater than its width. In the exemplary embodiment shown, the laser beam head is moved for line-by-line engraving in the direction of the longitudinal edges of the press plate and transversely thereto. In a modification of the embodiment shown in the drawing, it is also possible that the table 29 is moved in the longitudinal and transverse directions of the press plate 14 or 15 in the opposite manner and the laser beam head is stationary. It is also possible that the laser beam head 27 is moved in one direction and the table 29 in the other direction. A magnetic tape is advantageously used as the memory for the data to be fed into the computer.

In the examples shown, the laser beams act on one full-surface carrier web made of plastic, elastomer or a galvanic metal layer, which the press plate and / or cover the continuous sheet. The laser beams are in their Intensity controlled so that that generated by the laser beams Embossed structure only the thickness of the carrier web or the carrier layer detected, d. H. the carrier web or the cover layer is in their Thickness only textured until the surface is shiny metal the press plate or the endless belt are exposed, so that the subsequent etching treatment is then carried out can be.

Claims (7)

1. A method for applying embossed engravings by using laser beams on large-format metal press plates and / or endless belts for the surface treatment of sheets or plates made of plastic, wood or press laminates for use in discontinuously or continuously operating heating presses, characterized in that the press plate and / or the continuous bath is first coated with a full-surface carrier web made of plastic, an elastomer, or with a galvanic metal layer or coated with an etch-resistant color film, and that the laser beams are used to produce an embossed structure that only detects the thickness of the carrier web or the coating, and then that bare metal points of the pressing points and / or the endless belts are subjected to an etching treatment. 2. The method according to claim 1, characterized in that the coating of the endless belt remaining after the etching treatment and / or the press plate by means of a solvent Will get removed. 3. The method according to claims 1 or 2, characterized in that that the embossing processes one or more times be repeated. 4. The method according to claims 1 to 3, characterized in that on the press plates and / or endless belts Design image to be transmitted on one with the laser beams controlling connected magnetic tape stored becomes.   5. The method according to claims 1 to 4, characterized in that the relative movement during the action of the laser beams between the press plate and / or the endless belt and the laser beam head is coordinated. 6. The method according to claim 5, characterized in that while the structure of the laser beam head is fixed, while the endless belt and / or the press plate line by line moved, or vice versa. 7. The method according to claims 1 to 6, characterized in that that the relative movement between the endless belt and the Laser beam head is coordinated so that the beginning of engraving and the end of the engraving is a precise registration form.