Method for producing a paper machine clothing

Abstract

A method for producing a paper machine clothing includes the following steps: a) providing a film-like substrate having an upper face and a lower face opposite the upper face; b) forming a pattern of holes in the substrate by boring a multiplicity of holes, which connect the upper face to the lower face, into the substrate by way of at least one laser light source. A bore hole strategy is applied which ensures that, in temporal sequence between the forming of a first hole and an immediately adjacent second hole in the pattern of holes, at least one further hole of the pattern of holes is formed in the substrate which is not immediately adjacent either the first hole or the second hole in the pattern of holes.

Claims

1. A method of producing a paper machine clothing, comprising the following steps: providing a film-like substrate having an upper side and a lower side opposite the upper side; forming a pattern of holes in the substrate by boring a multiplicity of holes connecting the upper side with the lower side into the substrate with at least one laser light source; in the forming step, applying a bore hole strategy which ensures that, chronologically between an introduction of a first hole and a second hole that is immediately adjacent the first hole in the pattern of holes, at least one further hole of the pattern of holes is introduced into the substrate which is not immediately adjacent the first hole or the second hole in the pattern of holes; and wherein a spacing distance between two holes that are introduced chronologically in direct succession into the substrate is at least two times as great as a smallest spacing distance between two immediately adjacent holes in the pattern of holes.

2. The method according to claim 1, which comprises applying the bore hole strategy to a majority of the holes of the pattern of holes.

3. The method according to claim 2, which comprises applying the bore hole strategy to all the holes of the pattern of holes.

4. The method according to claim 1, wherein the at least one further hole is one of at least two further holes and the bore hole strategy provides, chronologically between the introduction of the first hole and the second hole immediately adjacent the first hole, for introducing the at least two further holes into the substrate, with none of the at least two further holes being immediately adjacent the first hole or the second hole.

5. The method according to claim 1, wherein the at least one further hole is one of at least three further holes and the bore hole strategy provides, chronologically between the introduction of the first hole and the second hole immediately adjacent the first hole, for introducing the at least three further holes into the substrate, with none of the at least three further holes being immediately adjacent the first hole or the second hole.

6. The method according to claim 1, wherein the at least one further hole is one of at least four further holes and the bore hole strategy provides, chronologically between the introduction of the first hole and the second hole immediately adjacent the first hole, for introducing the at least four further holes into the substrate, with none of the at least four further holes being immediately adjacent the first hole or the second hole.

7. The method according to claim 1, wherein the spacing distance between the two holes that are introduced chronologically in direct succession into the substrate is at least three times or at least four times as great as the smallest spacing distance between the two immediately adjacent holes in the pattern of holes.

8. The method according to claim 1, which comprises moving the laser light source relative to the substrate during the forming step.

9. The method according to claim 8, which comprises carrying out a movement of the laser light source relative to the substrate substantially discontinuously.

10. The method according to claim 8, which comprises carrying out a movement of the laser light source relative to the substrate substantially continuously.

11. The method according to claim 8, which comprises tensioning the substrate during the forming step by way of at least two rotatable rollers having mutually parallel roller axes.

12. The method according to claim 11, which comprises arranging the laser light source over the substrate and moving the laser light source relative to the substrate parallel to the roller axes.

13. The method according to claim 1, wherein the at least one laser light source is one of a plurality of laser light sources and the forming step comprises simultaneously using the plurality of laser light sources in order to introduce holes into the substrate.

14. A method of producing a paper machine clothing, comprising the following steps: providing a film-like substrate having an upper side and a lower side opposite the upper side; forming a pattern of holes in the substrate by boring a multiplicity of holes connecting the upper side with the lower side into the substrate with at least one laser light source; in the forming step, applying a bore hole strategy which ensures that, chronologically between an introduction of a first hole and a second hole that is immediately adjacent the first hole in the pattern of holes, at least one further hole of the pattern of holes is introduced into the substrate which is not immediately adjacent the first hole or the second hole in the pattern of holes; and using scanner optics for displacing a laser beam from the laser light source in jumps on the substrate, for carrying out the bore hole strategy.

15. The method according to claim 14, wherein the scanner optics comprises at least one movable mirror.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) Two exemplary embodiments of the method according to the invention will be described in more detail below with the aid of FIGS. 3 and 4, in which:

(2) FIG. 1 is a diagrammatic side view of a device showing a prior art method of perforating a substrate;

(3) FIG. 2 is a plan view thereof;

(4) FIG. 3 shows a first exemplary embodiment of the method according to the invention;

(5) FIG. 4 shows a second exemplary embodiment of the method according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(6) FIG. 3 schematically illustrates an exemplary embodiment example of the method according to the invention. A small section of a film-like substrate 10, which has a predetermined pattern of holes, may be seen, the holes of the pattern of holes being introduced into the film-like substrate 10 by means of a laser light source 14. In this case, as represented in FIGS. 1 and 2 and described in the introduction in connection with the prior art, the substrate 10 may be tensioned by means of two rollers 12, the laser light source 14 being arranged movably relative to the substrate 10, parallel to the axes of the rollers 12. Unlike in the embodiment known from the prior art, however, here the holes are not introduced successively into the substrate in a row. Rather, scanner optics (not represented) are used, which make it possible to cause a laser beam from the laser light source 14 to jump within a very short time from one location on the surface of the film-like substrate 10 to another location of the surface. In the present example, the scanner optics encompass the entire section, represented in FIG. 3, of the substrate 10.

(7) The chronological order with which the holes 1-8 of the pattern of holes are introduced into the film-like substrate is represented by the arrows and the numbering in FIG. 3. Assuming that the left edge of the section shown in FIG. 3 corresponds to one of the two side edges of the film-like substrate 10, a first hole 1 is introduced into the film-like substrate 10 in the vicinity of the side edge. Subsequently, the scanner optics ensure that, although the second hole 2 is introduced in the same row as the first hole 1, the hole 2 is not immediately adjacent to the hole 1. Rather, in this embodiment example 10 holes of the pattern of holes are arranged between the hole 1 and the hole 2. After the introduction of the hole 2, the scanner optics ensure that the next hole 3 is likewise introduced at a position which is not immediately adjacent to the hole 2. Rather, in this embodiment example the hole 3 is introduced four rows below the hole 1. The next hole 4 is in turn not introduced immediately adjacent to the hole 3. Rather, although it is introduced in the fourth row, i.e. the row of hole 3, it is introduced below hole 2, so that in this embodiment example 10 further holes of the pattern of holes are arranged between hole 3 and hole 4. The same jump sequence is subsequently repeated, but shifted by one hole to the right in FIG. 3. Therefore hole 5 is introduced immediately adjacent to hole 1 in the first row. Hole 6 is introduced immediately adjacent to hole 2 in the first row. Hole 7 is introduced immediately adjacent to hole 3 in the fourth row. Hole 8 is introduced immediately adjacent to hole 4 in the fourth row. The scheme is repeated until all holes between hole 1 and hole 2 in the first row have been introduced into the film-like substrate 10, i.e., until all the holes represented in FIG. 3 in rows 1 and 4 have been generated. Following this, the laser light source 14 is moved to the right relative to the substrate 10, outside the image region of FIG. 3, in order to perforate the first and fourth rows of a further section of the film-like substrate 10 there. As soon as the opposite side edge of the film-like substrate 10 is reached, the film-like substrate 10 may be moved forward by means of the rollers 12 so that the next rows, for example rows 2 and 5, can be introduced according to the bore hole strategy according to the invention, until the entire film-like substrate 10 is provided with the predetermined pattern of holes.

(8) FIG. 4 schematically illustrates an alternative second exemplary embodiment example of the method according to the invention. It differs from the first embodiment example in that two times the distance in comparison with the first embodiment example is left between the holes 1 and 5 as well as between the holes 2 and 6 in the first row, and between the holes 3 and 7 as well as between the holes 4 and 8 in the fourth row. The effect of this is on the one hand that the introduction of the holes in the first and fourth rows can take place substantially continuously over the entire length of these rows when the laser light source 14 is moved constantly relative to the film-like substrate 10, parallel to the axes of the two rollers 12. This has the advantage that the method can be carried out even more rapidly than in the case of the first embodiment example, in which the rows are introduced in sections and therefore substantially discontinuously.

(9) On the other hand, the effect of the method according to the second embodiment example is that the hole spacing in the edge region of the film-like substrate 10 (on the left in FIG. 3) is greater than in the central region of the substrate 10 (on the right in FIG. 3). This is advantageous since the substrate 10 in this way has a greater strength in the edge region. In this case, it should be noted that in the edge region of the substrate 10 it is less important for the holes to lie close to one another, since accurate formation of the fibrous material web is not essential in this region. Usually, no fibrous material at all is applied onto this region.

(10) By the method according to the invention, it is possible to perforate the film-like substrate 10 much more rapidly than with the method described in the introduction from the prior art, since the individual holes can be introduced more rapidly in succession without the substrate 10 locally experiencing a critical energy input and being damaged.

LIST OF REFERENCES

(11) 1′, 2′, 3′ holes 1-8 holes 10 film-like substrate 12 roller 14 laser light source