DE102018102718A1 - Method for machine laser groove of use as well as three-dimensional structure manufacturable therewith - Google Patents

Abstract

The invention relates to a method for mechanically laser-curving a sheet (6) of a foldable material, wherein by means of a laser in a surface (7) of the sheet (6) laser lines (2) are introduced to form folding surfaces (3), wherein between narrow adjacent laser lines (2) in each case a separating web (4) is left and that to form a first folding surface (3) M laser lines (2) and to form a second folding surface (3) N laser lines (2) are lasered into the arc, wherein the M laser lines at an angle to the N laser lines (2) and wherein the number M is selected differently from the number N (Fig. 1).

Description

The invention relates to a method for mechanically laser-curving a sheet of a foldable material, laser lines being introduced into a surface of the sheet by means of a laser in order to form folding surfaces.

The invention further relates to a three-dimensional structure that can be made by machine laser flanging sheets of foldable material.

To produce creasing lines, the method of hollow grooving is still widely used today. However, attempts have been made since the beginning of the 1990s to use lasers in the processing of sheets of foldable material, in the hope of enabling a more flexible and cost-effective production. Typically, these applications relate to sheets having a plurality of so-called benefits, each of which can be used to produce a three-dimensional structure, such as a carton for packaging pharmaceuticals or the like.

Accordingly, methods and structures as mentioned above are already known in a variety of embodiments and are already used in particular for the production of folding cartons.

For example, in the prior art, lasers are used to separate individual benefits from a sheet of foldable material. In these applications, a laser beam thus cuts through the material along cutting lines.

In addition, it is also known to remove material using lasers targeted, which is possible, for example, for paper or cardboard. By means of such a laser beam ablation, the material thickness of a sheet can be reduced in a targeted manner, wherein a laser line is formed in a surface of the sheet when the laser beam is guided along a line.

By forming a laser line by laser ablation in a surface of a sheet, a groove is formed. The cross-sectional profile of this groove is dependent on both the material of the sheet and the intensity profile of the laser beam used. For example, by suitable beam shaping and choice of the intensity of the laser beam, it is possible to apply approximately V-shaped grooves as laser lines.

Due to the precisely adjustable material removal by means of a laser, therefore, so-called creasing, bending or folding lines can be formed as laser lines in the surface of the sheet. This process is referred to below as laser grooves.

In laser-cut creasing, bending or folding lines in the form of laser lines, the laser beam thus only partially carries off the material, so that a residual material thickness r remains; this results as the difference between the groove depth d the groove and the material thickness t of the arc: r = t - d. The groove depth d can be defined as a distance between a groove bottom of the groove and the surface of the arc, in which the groove was lasered.

Through the groove, the arc is locally weakened in the region of the laser line in its rigidity. This is used to subsequently define a folding surface along the laser line. If the material is unfolded along the laser line, a three-dimensional structure is created.

In addition, it is also known to ablate material on a surface basis with the aid of lasers, the laser also typically being guided along a line pattern here. In contrast to the application of defined laser lines, however, the areas in which material is removed by laser ablation overlap, in this case, whereby the desired areal removal is achieved.

In summary, lasers are already used in the prior art in order to groove, cut, punch or perforate the benefits from which folding cartons can be produced.

The object of the present invention is to provide an advantageous method for machine laser grooves of use, so that three-dimensional structures, in particular folding boxes, can be produced flexibly and inexpensively. In addition, three-dimensional structures are to be proposed, which can be conveniently manufactured.

To achieve this object, the features of claim 1 are provided according to the invention in a method of the type described above. In particular, it is thus proposed according to the invention for achieving the object in a method for machine laser fluting of sheets of the type described above that a respective separating web is left between adjacent laser lines of each folding surface and for forming a first folding surface M Laser lines and to form a second folding surface N Laser lines are lasered into the material, the M Laser lines at an angle to the N Laser lines run and where the number M different from the number N is selected. Here, the respective M or. N laser lines each preferably be introduced parallel to each other extending into the sheet material. It is furthermore particularly advantageous if the laser lines run parallel to the fold surface to be formed in each case.

According to the invention, the laser lines can therefore be laser-separated from one another by separating webs into the material. Furthermore, it can be provided that a single laser line corresponds precisely to the removal of material, which results from a single, preferably continuous, guiding of the laser over the surface of the sheet. In other words, therefore, a single laser line, or the groove produced by it in the surface of the sheet, in particular already be formed by a one-time process of the laser along the laser line.

As has been shown by experiments, can be achieved by the inventive design of the laser lines both excellent dimensional stability and a high restoring force in the field of individual folding surfaces.

Both of these factors play a crucial role in efficiently producing three-dimensional structures, such as folding cartons by folding, from the benefits produced by the method of the invention. For a high dimensional stability and high restoring forces in the field of folding surfaces are particularly for machine folding the benefits of great advantage. For such processes defined attack surfaces are needed, at which the folding machines used can attack on a not yet folded benefits.

So far, it has been customary to select the number of laser lines, in particular those which define folding surfaces, depending on the sheet material and the material thickness of the sheet and to select the number of laser lines for each folding surface the same.

However, the invention has recognized that the provision of a different number of laser lines, depending on the orientation of the fold lines (bending lines) or the associated folding surfaces is particularly favorable to minimize the process time for the laser grooves and at the same time to ensure the desired dimensional stability. The method according to the invention therefore offers advantages in terms of throughput per hour as compared to methods known in the art as well as in terms of the quality of the folding surfaces defined by the method. Because the total number of necessary trainees laser lines per sheet is optimized or minimized by the inventive method. This improvement represents a decisive advantage, in particular in applications where a high throughput significantly determines the costs of producing the benefits.

By means of the invention, in particular rounded edge regions can be formed and thus an appealing exterior of three-dimensional structures produced from the utility, such as folding boxes. For this purpose, for example, the folding surface associated with a bending line may be delimited by two folding lines running parallel to the bending line and designed as laser lines. In order to support the rounding laser lines can then be introduced according to the method described above within the folding surface.

Thus, according to the invention, it can thus be provided in particular that the M laser lines extend within the first fold surface and the N laser lines within the second fold surface.

According to the invention, the object can also be achieved by further advantageous embodiments according to the subclaims.

If, for example, laser lines are applied particularly closely adjacent to one another, as is required in some applications, it may happen that the separating webs in between also show a material removal by the laser. In such a case, the laser-facing surface of the separating web is thus deeper than the surface of the sheet.

In such an embodiment, it is conducive to a sufficiently high dimensional stability of the folding surfaces when the laser lines are introduced into the sheet so that a material removal in the region of the partitions less than 50%, but preferably less than 30%, a groove depth d a groove formed by one of the laser bars adjacent to the divider.

In other words, the laser lines and the grooves introduced through them into the sheet can be configured such that a height of a separating web, measured over the groove bottom of a groove, is at least half, preferably at least two-thirds or 75%, very particularly preferably at least 90 % or even 100% of the groove depth of a groove.

The dividers can hereby stabilize the folding surface in the use position, for example, by the fact that adjacent dividers are supported against each other. Here it is particularly favorable if the dividers a height H as large as possible.

It is thus particularly preferred if the material removal in the region of the partitions is less than 10% of an associated groove depth d or if no material at all in the region of the partitions is removed by the laser. In the latter case, the laser-facing surface of a separating web is thus at the level of the surface of the sheet. This can be achieved, for example, by a suitable beam shaping as well as a suitable choice of the intensity of the laser, depending on the material of the sheet to be lasered.

If sheets are to be laser-etched, which consist of a fiber-containing material, then it is particularly advantageous according to the invention, if the N Laser lines run along a fiber direction of the material and that the number N less than the number M is selected. Here, the M Laser lines preferably extend at an angle to the fiber direction.

In other words, it can thus be provided that for folding surfaces, which are to be folded along a fiber direction of the sheet material, a smaller number N is formed on laser lines as in such folding surfaces, which are to be folded obliquely to the fiber direction. The invention has thus recognized that the different stiffness of the sheet material can be taken into account in different directions in the design of the laser rinsing to minimize the process time and yet to ensure a consistently high dimensional stability of the folding surfaces, regardless of their orientation.

In general, it is advantageous according to a further embodiment, if the numbers N and M each greater than 1 , preferably greater than 2 , to get voted. Thus, it can be provided that at least two, preferably at least three laser lines are to be lasered into the sheet per folding surface to be applied, preferably independently of their orientation.

A particularly favorable relationship between the process time required for the laser-curving of a sheet and the dimensional stability of the resulting fold surfaces can be achieved according to further embodiments, if for the ratio of the numbers M: N a value of 4: 3 or 5: 4 or 5: 3 is selected. The ratio M: N may for example denote a relation between the number of M Laser lines that define a first folding surface and a number N of laser lines defining a second fold surface of the sheet. Here, the M Laser lines in particular obliquely or perpendicular to the N Laser lines run. It has proven to be advantageous if a selected ratio of M: N for all folding surfaces of a sheet, depending on their orientation, is maintained.

According to a development of the invention, it is advantageous if laser lines which define a folding surface and / or extend within a folding surface are lasered substantially parallel, preferably exactly parallel, to a bending line belonging to this folding surface. Because of such an arrangement, the dimensional stability of the folding surface is increased.

According to a further embodiment, it may be provided that the laser lines are lasered into the sheet as grooves which do not perforate the sheet, preferably with a cross-sectional profile tapering towards the outside of the net.

According to a further advantageous embodiment, it is provided that the surface into which the laser lines are introduced is an inside of a benefit. Thus, the laser lines may not be visible from the outside, for example, in a three-dimensional structure to be produced from the benefit.

According to the invention, it is generally advantageous if a width of a single laser line is chosen to be greater, the greater the material thickness of the material. This approach has proven to be favorable for a high throughput while maintaining sufficient dimensional stability of the folding surfaces.

To solve the object mentioned at the outset, the features of the claim directed to a three-dimensional structure are alternatively provided. Thus, in order to achieve the object for a three-dimensional structure which can be produced by means of laser grooves, it is proposed that the structure on one of its surfaces have closely spaced lasered grooves which are each separated by a separating web M lasered grooves form a first fold surface of the structure and N Further lasered grooves, which, based on the surface, at an angle to the M lasered grooves, forming a second folding surface of the structure and wherein the number M is different from the number N is.

Such a three-dimensional structure can be produced particularly efficiently and thus cost-effectively by means of the method according to the invention for the automatic laser flashing of sheets.

According to the invention, furthermore, a three-dimensional structure can be produced particularly favorably by means of laser grooves, when the structure in unfolded state has folding surfaces extending in an angle to one another, in particular at right angles, and in each case different numbers within these folding surfaces M . N are formed by lasered grooves. In this case, it is preferred if the lasered-in grooves are essentially parallel, particularly preferably run exactly parallel to bending lines of the folding surfaces.

Such a structure can also be produced particularly efficiently and thus cost-effectively with the method according to the invention for machine-laser blading of sheets.

If the three-dimensional structure of a sheet material having fibers, it is also particularly preferred if the number N less than the number M is, where the N Laser lines run in a fiber direction of the sheet material and the M Laser lines extend obliquely to the fiber direction.

The invention will now be described in more detail with reference to embodiments, but is not limited to these embodiments.

Further exemplary embodiments result from the combination of the features of individual or several protection claims with one another and / or with one or more features of the respective exemplary embodiment. In particular, embodiments of the invention can thus be obtained from the following description of a preferred embodiment in conjunction with the general description, the claims and the drawings.

• 1 Einen Nutzen, der mittels des erfindungsgemäßen Verfahrens hergestellt wurde, und
• 2 einen Schnitt durch eine Laserlinie in schematischer Darstellung.

It shows:

• 1 A benefit, which was produced by the method according to the invention, and
• 2 a section through a laser line in a schematic representation.

The 1 shows a total of 1 designated benefits that from a bow 6 was cut out of foldable material, the bow 6 and therefore the benefits 1 was processed by the method according to the invention. The use 1 has several bending lines 5 as well as related folding surfaces 3 on. By folding along the bend lines 5 can the benefit 1 in a three-dimensional structure, in the 1 shown example, a packaging box to be transferred.

Like the circular detail on the left in 1 shows, the (in the picture) vertically extending folding surface 3 a total of three parallel and (pictured) vertically extending laser lines 2 on, while within the (in the picture) horizontally extending folding surface 3 a total of four (in the picture) horizontal and parallel laser lines 2 are formed.

This embodiment is based on the consideration of the fiber orientation of the material, from which the benefits 1 consists. In the example shown, the fiber-running direction runs from top to bottom (ie in the same direction as the three laser lines running vertically in the detail section) 2 ). Thus, more laser lines are introduced only in the direction in which the sheet material has a higher rigidity (in the example, the horizontal direction) than in this oblique, ie in particular vertical, directions. Shown here is M = 4 and N = 3, but other values can also be selected.

2 shows a schematic sectional view through an arc 6 , The material thickness t of the bow 6 results from the distance of the surface 7 and the outside 9 , The laser lines 2 (in the example of the 2 three laser lines 2 ) are each as a groove 8th formed, which has a groove depth d having. This leaves a residual material thickness r to the outside 9 ,

The laser lines 2 define a folding surface 3 that when folded along the laser lines 2 on the outside 9 is tense.

Between the grooves 8th each is a divider 4 trained, who has stopped while lasing. The height H the dividers 4 is more than 50% of the groove depth d , These dividers 4 give the folding surface 3 in the bent state additional stability.

In summary, it is useful for efficient production 1 from which three-dimensional structures can be produced by folding, a specific method for laser grooves of use 1 or a specific embodiment of the benefits 1 proposed. This provides that by means of a laser several laser lines 2 in the form of groove-shaped depressions or grooves 8th in a surface 7 of utility 1 preferably ablativ lasered, the wells by raised dividers 4 are separated from each other and where the benefit 1 in the area of the depressions and / or along the depressions or grooves 8th is unfoldable. In order to achieve a high level of efficiency in production while maintaining the high dimensional stability of the developed folding surfaces 3 To achieve this is a number of laser lines 2 in a fold surface 3 is formed depending on the orientation of this fold surface 3 chosen differently high, so folding surfaces 3 with the same orientation an equal number of laser lines 2 and those with different orientations have an uneven number of laser lines 2 respectively.

LIST OF REFERENCE NUMBERS

1

Use

2

laser line

3

Folding surface (laser cleaning)

4

divider

5

elastic line

6

arc

7

surface

8th

groove

9

outside

10

Grain direction

r

Residual material thickness

t

material thickness

d

groove depth

H

Height of 4

Claims (11)

Method for mechanically laser-curving a sheet (6) of a foldable material, wherein laser lines (2) are introduced by means of a laser into a surface (7) of the sheet (6) to form folding surfaces (3), characterized in that between adjacent laser lines (2) each folding surface (3) in each case a separating web (4) remains and that for forming a first folding surface (3) M, preferably parallel laser lines (2) and for forming a second folding surface (3) N, preferably parallel to each other , Laser lines (2) are lasered into the sheet (6), wherein the M laser lines are at an angle to the N laser lines and wherein the number M is selected differently from the number N. Method according to Claim 1 , characterized in that the N laser lines (2) run along a fiber direction (10) of the material and that the number N is selected smaller than the number M, preferably wherein the M laser lines (2) at an angle to the fiber direction (10) run. Method according to Claim 1 or 2 , characterized in that the numbers N and M are each greater than 1, preferably greater than 2, are selected. Method according to one of the preceding claims, characterized in that for a ratio M: N a value of 4: 3 or 5: 4 or 5: 3 is selected. Method according to one of the preceding claims, characterized in that laser lines (2) within a folding surface (3) substantially parallel, preferably exactly parallel, to one of the folding surface (3) associated bending line (5) extending in the arc (6) are lasered , Method according to one of the preceding claims, characterized in that the laser lines (2) as the arc (6) non-perforating grooves (8), preferably with a to the outside (9) of the arc (6) towards tapered cross-sectional profile, in the arc (6) are lasered. Method according to one of the preceding claims, characterized in that the surface is an inside of a utility (1), in particular so that the laser lines (2) are not visible from outside in a three-dimensional structure to be produced from the utility (1). Method according to one of the preceding claims, characterized in that the separating webs (4) are left with a height (h) which is at least 50% or at least two-thirds, preferably at least 75%, more preferably at least 90% or even 100% of a groove depth (d) the grooves (8) is. Three-dimensional structure which can be produced by means of laser grooves, in particular folding box, characterized in that the structure preferably has closely spaced lasered grooves (8) on one of its surfaces (7), which are each separated by a separating web (4), M being laser lines (2) , in particular lasered grooves (8), form a first folding surface (3) of the structure and N further laser lines (2), in particular lasered grooves which run at an angle to the M laser lines (2), a second folding surface (3) of the structure and wherein the number M is different from the number N. Three-dimensional structure, in particular folding box, preferably according to Claim 9 , characterized in that the structure in unfolded state in one, in particular right, angle to each other extending folding surfaces (3), wherein within these folding surfaces (3) each different numbers M, N of laser lines (2) are formed, preferably wherein the laser lines (2) each folding surface (3) substantially parallel to each other, particularly preferably exactly parallel to each other, run. Three-dimensional structure, in particular folding box, according to Claim 9 or 10 , characterized in that the number N is smaller than the number M, wherein the N laser lines (2) in a fiber direction (10) of a sheet material, of which the structure consists, run and the M laser lines (2) obliquely to the fiber direction ( 10).

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