METHOD FOR FORMING AND DETECTING SECURITY ELEMENTS ON THE SURFACE OF A COMPONENT OR IN A COMPONENT, AND SYSTEM FOR DETECTING SAID SECURITY ELEMENT

Abstract

The invention relates to a method for forming and detecting security elements on the surface of a component and/or in a component, in which at least one layer or at least one region that is preferably formed of a magnetic material or of a material different from the component material is formed on the surface of the component and/or in the component that is formed of a magnetic or of a nonmagnetic material in a locally and geometrically defined manner. At least one ablated track, at least one heat-affected region and/or at least one remelted treatment track are/is formed by a locally and geometrically defined ablation of material or input of energy on/at the surface of a component along a predefined contour corresponding to the respective security feature. In the manufacture of the component, a magnetic material different from the material of the component is introduced into the component at at least one predefined position in a locally and geometrically defined manner by way of a generative production process. To detect the security element, a magnetization unit is used to generate at least one magnetic field penetrating into the component or a magnetic flux is produced inside the magnetization unit that penetrates into the component. To check a security element formed in this way, a detection unit is used to detect the magnetic stray fields occurring on the security element as a result of the at least one magnetic field, and the measurement signals captured by the detection unit are transferred to an evaluation unit having an image-processing or pattern-recognition system. Using the evaluation unit having an image-processing or pattern-recognition system, it is checked, by way of the detected magnetic stray fields, whether or not the detected security element corresponds to a specification.

Claims

1. A method for forming and detecting security elements on the surface (1a) of a component (1) and/or in a component (1), in which at least one layer or at least one region that is preferably formed of a magnetic material or of a material different from the component material is formed on the surface (1a) of the component (1) and/or in the component (1) that is formed of a magnetic or of a non-magnetic material in a locally and geometrically defined manner, wherein at least one ablated track (2), at least one heat-affected region (6) and/or at least one remelted treatment track (9) are/is formed by a locally and geometrically defined ablation of material or input of energy on/at the surface (1a) of a component (1) along a predefined contour corresponding to the respective security feature (S) or in the manufacture of the component (1), a magnetic material (16) different from the material of the component (1) is introduced into the component (1) at at least one predefined position in a locally and geometrically defined manner by way of a generative production process and to detect the security element (S), a magnetization unit is used to generate at least one magnetic field penetrating into the component (1) or a magnetic flux is produced inside the magnetization unit that penetrates into the component (1) and to check a security element (S) formed in this way, a detection unit (10) is used to detect the magnetic stray fields occurring on the security element (S) as a result of the at least one magnetic field, and the measurement signals captured by the detection unit are transferred to an evaluation unit having an image-processing or pattern-recognition system, and using the evaluation unit having an image-processing or pattern-recognition system, it is checked, by way of the detected magnetic stray fields, whether or not the detected security element (S) corresponds to a specification.

2. The method as claimed in claim 1, characterized in that a locally and geometrically defined ablation of material and/or input of energy for forming a security element (S) is achieved by way of an energy beam, preferably a laser beam, electron beam or ion beam.

3. The method as claimed in claim 2, characterized in that a further material (16) introduced into the inside of the component (1) is a non-magnetic material or a magnetic material different from the material of the component (1).

4. The method as claimed in claim 1, characterized in that at least one ablated track (2) is at least partially filled with a material different from the component material, preferably a non-magnetic material.

5. The method as claimed in claim 1, characterized in that a security feature (S) not visible to the eye without auxiliary means and not haptically recognizable without auxiliary means is formed.

6. The method as claimed in claim 1, characterized in that a preferably optically non-transparent top layer, preferably a varnish or an insulation layer, is applied to a security element (S) that is formed on the surface (1a) of a component (1).

7. The method as claimed in one of the preceding claims, characterized in that machine-readable one-dimensional, two-dimensional or quasi-three-dimensional information is formed on the security feature (S).

8. A system for use in a method as claimed in claim 1, wherein the system consists of a magnetization unit by way of which, at least in that region of the component (1) in which a security feature (S) has been formed, magnetization of a magnetic material present there can achieved, and a detection unit (10) for detecting magnetic stray fields generated in the component (1), and an evaluation unit having an image-processing or pattern-recognition system for evaluating or recognizing the detected magnetic stray fields and for checking whether or not the captured measurement signals correspond to a specification for a security feature (S).

9. The system as claimed in claim 8, characterized in that the detection unit contains a magneto-optical sensor that can used together with a magnetic layer having high anisotropy, or at least one inductive or capacitive sensor detecting in a spatially resolved manner.

10. The system as claimed in claim 8, characterized in that the magnetic stray fields can generated by induction of a magnetic flux or by way of at least one static magnetic field.

11. The system as claimed in claim 8, characterized in that a resolution in the range of 5 m to 100 m, preferably in the range of 5 m to 25 m, can achieved by way of the detection unit.

12. The system as claimed in claim 8, characterized in that the detection unit (10) is formed so as to examine the security element (S) in partial regions of the security element (S).

Description

[0040] The invention is intended to be explained in further detail below with reference to examples. In the figures:

[0041] FIG. 1 shows a depiction in principle of the refinement of an exemplary security element,

[0042] FIG. 2 shows possible refinement variants of the method for producing a security element according to the invention,

[0043] FIG. 3 shows an example of the detection of security features,

[0044] FIG. 4 shows a depiction in principle of the application of an exemplary security element and of a top layer, and

[0045] FIG. 5 shows a depiction in principle of the formation of an exemplary security element during a generative production process.

[0046] FIG. 1 is a depiction in principle of the refinement of an exemplary security element S on a surface 1a of a component 1. The component is formed from an unalloyed structural steel for parts in general mechanical and vehicle construction C40E (material number 1. 1186). After three irradiation procedures using a laser beam 3 having a focal spot feed rate of 1 m/s, a power of 100 W and a focal diameter of 29 m, a geometrically and locally defined ablation of material 4 in the form of a logo was achieved in the component 1. The focal spot was thus moved along the contour of the security feature S three times.

[0047] The cross section of the region referenced A is shown in the right-hand part of FIG. 1. An ablated track 2 is formed by the ablation of material, the geometric formation of which track is influenced by the parameters of the laser beam 3. In the region around the ablated track 2, a heat-affected region 6, in which the micromagnetic structure of the material changes, is generated by the heat treatment by way of the laser beam. This region is likewise part of the security element 5, as is the ablated track 2. The ablated track 2 had a depth of 25 m and a width of 50 m. The heat-affected region 6 had a width of 50 m next to the ablated track 2.

[0048] FIG. 2 depicts principle refinement variants of the method for manufacturing a security element S according to the invention on the surface 1a of a component 1.

[0049] In refinement variant A, a treatment track 5 was melted in a locally and geometrically defined manner on the surface 1a of the component 1 by way of a laser beam 3, which treatment track subsequently resolidified, i.e. was remelted. A heat-affected region 6 formed in the region of the treatment track 5. As a result of the heat treatment, the micromagnetic structure of the component material was changed both in the treatment track 5 and in the heat-affected region 6. This change is able to be recognized in the detection of the security element S and in the evaluation of the magnetic stray fields forming in the component 1, and viewed on a display apparatus.

[0050] In refinement variant B, the form and depth of the treatment track 5 and of the heat-affected region 6 was varied in comparison to refinement variant A by varying the parameters of the laser beam 3. In this case, in comparison with refinement variant A, the size of the area of the focal spot was not changed, the number of irradiation procedures was reduced, the power used was increased and/or the feed rate of the focal spot of the energy beam was increased. The formation of the security element S is able to be influenced in a targeted manner by way of such variations.

[0051] In refinement variant C, a combination of an ablated track 2 and a melted and resolidified treatment track 5 on the surface 1a of a component 1 is depicted. In this case too, a heat-affected region 6 formed as part of the security element S. This is able to be achieved by increasing the number of irradiation procedures without the area of the focal spot being changed, by reducing the power used and/or increasing the feed rate of the focal spot movement in comparison with the formation in refinement variant A.

[0052] Refinement variant D shows how, by changing the process parameters of the laser beam 3, the geometry of the ablated track 2, of the treatment track 5 and of the heat-affected region 6 is able to be achieved in comparison with refinement variant A. In this case, the following procedure may be adopted: the number of irradiation procedures without the area of the focal spot being changed is increased, the power used is increased and/or the feed rate is increased.

[0053] As an alternative, as depicted in refinement variant E, in the case of such a thermal treatment, the surface tension state of the molten material may also be utilized such that a resolidified track with a triangular cross section is formed. This may be achieved by adopting the following procedure in comparison with refinement variant A: the number of irradiation procedures without the area of the focal spot being changed is increased, the power used is reduced and/or the feed rate of the focal spot movement of the energy beam is reduced.

[0054] FIG. 3A schematically shows the measurement principle for the detection of a magnetically active security element S that is created by a track formed by way of a laser beam 3 by way of refinement variant C from FIG. 2.

[0055] If a magnetic flux 8 is induced in the component 1 in the region 10a to be examined, said flux impinges on the region of the removed material in the region of the ablated track 2 and, at the material/air interface, potentials having a corresponding magnetic structure form, which in turn lead to unidirectional magnetic stray fields 7 coming from magnetic poles 9 formed in a locally limited manner. As an alternative, the component 1 may also be magnetized by way of static magnetic fields.

[0056] The perpendicular field components of the magnetic stray fields 7 are able to be captured using a detection unit 10 and a graphic depiction 11 is able to be transferred to a display apparatus by an evaluation unit. An alternative to detecting the perpendicular field components of the magnetic stray fields 7 is to determine the magnetic structure in the region of the magnetic poles 9.

[0057] FIG. 3B shows a variant in which alternating magnetic fields are introduced into the component 1. Said magnetic poles 9 arise here in the region 5 of the molten and rapidly solidified magnetic material, a phase conversion being able to take place depending on the alloy.

[0058] FIG. 4 is a sectional depiction in principle of the formation of a security element S in the form of an ablated track 2 and the application of an opaque top layer 12 made from a colored pigment layer, varnish layer, polyether layer, calcium sulfate dihydrate layer or epoxy resin layer to the surface 1a of a component 1. The top layer 12 hides the security element S from being perceived by the naked eye or by haptic touch.

[0059] FIG. 5 shows a depiction in principle of an exemplary security element S during a generative production process.

[0060] During application-based production, a non-magnetic material, such as for example aluminum, is applied to a substrate 13 in layers in the form of powder 14 and sintered by way of a laser beam 3 (FIG. 5A). In doing so, locally defined recesses 15 are formed. These recesses 15 form the geometric shape of a product logo or company logo that is intended to serve as security element S. The recesses 15 are intended to be arranged at a spacing of at most 1 mm, preferably 0.3 mm, from the surface 1a of the component 1 once the component 1 is complete. The width and the height of the recesses 15 lie in the range of 50 m to 370 m.

[0061] A magnetic material 16, such as for example a ferromagnetic iron alloy, different from the material of the component 1 is then introduced into the recesses 15 (FIG. 5B). The powder of the introduced material 16 should have a permeability different from that of the material of the component, that is to say it should amplify normal external magnetic fields inside by a greater factor.

[0062] The introduced material 16 is melted locally by way of a laser beam 3, such that it adopts the cross section 17 of the previously formed free space (FIGS. 5C and 5D). In an alternative variant embodiment, the introduced material may be left in its original form.

[0063] By applying an additional top layer 12 made from the basic material or a material different from the basic material, it is possible to seal the security element S on the surface 1a of the component 1 (FIG. 5E), such that optical and/or haptic recognition is not possible without auxiliary means.