Method for marking workpieces and workpiece

Abstract

In an embodiment, the method includes providing a blank, applying a marking to the blank in places and heating the blank with the marking to a deformation temperature. The method further includes deforming the blank to form the workpiece and cooling the workpiece, wherein deforming is a hot forming, wherein the marking remains at the workpiece at least until after deforming and cooling, and is not destroyed by deforming, and wherein the marking has a difference in the degree of reflection and/or a difference in the degree of reflectance and/or a difference in albedo of at least 15 percentage points in at least part of the near ultraviolet, visible and/or near infrared spectral range both with respect to the blank and with respect to the workpiece.

Claims

1. A method for manufacturing a workpiece, the method comprising: providing a blank; applying a marking to the blank in places; heating the blank with the marking to a deformation temperature; and after heating, deforming the blank to form the workpiece and cooling the workpiece, wherein deforming is a hot forming, wherein the marking remains on the workpiece at least until deforming and cooling, wherein the marking is not destroyed by deforming, wherein the marking has a difference in the degree of reflection and/or a difference in the degree of reflectance and/or a difference in albedo of at least 15 percentage points in at least part of a near ultraviolet, visible and/or near infrared spectral range both with respect to the blank and with respect to the workpiece, wherein the marking is applied by at least one phosphor or comprises at least one phosphor which brings about the difference in a degree of reflection, wherein the blank comprises an anti-scaling protective layer to which the marking is directly applied, wherein a melting point of the marking is at least 25 C. above a melting point of the anti-scaling protective layer and both melting points are below the deformation temperature, wherein the marking or at least one constituent of the marking is pressed into the anti-scaling protective layer while heating and cooling, and wherein the marking differs from the blank and from the workpiece machine-readably at least in a visible spectral range.

2. The method according to claim 1, wherein the marking remains permanently on the workpiece, wherein the marking comprises a light-transmissive, inorganic matrix material, and wherein the marking is fixed to the blank and to the workpiece by the matrix material.

3. The method according to claim 2, wherein the matrix material is a light-transmissive inorganic material, and wherein the anti-scaling protective layer comprises aluminum, silicon, zinc, iron and/or a metal oxide.

4. The method according to claim 3, further comprising, after deforming and cooling, removing the marking in a dry process after step, wherein a material of the workpiece is not removed.

5. The method according to claim 4, wherein the marking comprises an organic matrix material, wherein the marking is fixed to the blank by the matrix material while applying the marking, and wherein the matrix material is decarbonized to the extent of at least 95% while heating and/or while deforming and cooling.

6. The method according to claim 1, wherein the marking, as seen in plan view, is formed by a plurality of punctiform, island-shaped partial regions having a mean diameter of at most 50 m, wherein the marking, as seen in plan view and considered with all partial regions taken together, has a mean extent of at least 20 times the mean diameter, and wherein a mean roughness of a surface of the workpiece at the marking deviates from a mean roughness of remaining regions of the surface by at most a factor of 2.

7. The method according to claim 1, wherein the marking is formed by at least one continuous marking region, wherein the at least one marking region has a mean extent of at least 20 times a mean diameter of color pigments of the marking.

8. The method according to claim 1, further comprising applying, after deforming and cooling, at least one lacquer to the workpiece such that the lacquer completely covers the marking and the marking is no longer discernible to an observer through the lacquer.

9. A method for manufacturing a workpiece, the method comprising: providing a blank; applying a marking to the blank in places; heating the blank with the marking to a deformation temperature; after heating, deforming the blank to form the workpiece and cooling the workpiece, wherein deforming is a hot forming, wherein the marking remains on the workpiece at least until deforming and cooling, wherein the marking is not destroyed by deforming, and wherein the marking has a difference in the degree of reflection and/or a difference in the degree of reflectance and/or a difference in albedo of at least 15 percentage points in at least part of a near ultraviolet, visible and/or near infrared spectral range both with respect to the blank and with respect to the workpiece; and after deforming and cooling, removing the marking in a dry process after step, wherein a material of the workpiece is not removed.

10. A method for manufacturing a workpiece, the method comprising: providing a blank; applying a marking to the blank in places; heating the blank with the marking to a deformation temperature; and after heating, deforming the blank to form the workpiece and cooling the workpiece, wherein deforming is a hot forming, wherein the marking remains on the workpiece at least until deforming and cooling, wherein the marking is not destroyed by deforming, wherein the marking has a difference in the degree of reflection and/or a difference in the degree of reflectance and/or a difference in albedo of at least 15 percentage points in at least part of a near ultraviolet, visible and/or near infrared spectral range both with respect to the blank and with respect to the workpiece, wherein the blank comprises an anti-scaling protective layer to which the marking is directly applied, and wherein the marking or at least one constituent of the marking is pressed into the anti-scaling protective layer while heating and cooling.

11. The method according to claim 10, wherein the marking remains permanently on the workpiece, wherein the marking comprises a light-transmissive, inorganic matrix material, and wherein the marking is fixed to the blank and to the workpiece by the matrix material.

12. The method according to claim 11, wherein the matrix material is a light-transmissive inorganic material, and wherein the anti-scaling protective layer comprises aluminum, silicon, zinc, iron and/or a metal oxide.

13. The method according to claim 10, further comprising, after deforming and cooling, removing the marking in a dry process after step, wherein a material of the workpiece is not removed.

14. The method according to claim 13, wherein the marking comprises an organic matrix material, wherein the marking is fixed to the blank by the matrix material while applying the marking, and wherein the matrix material is decarbonized to the extent of at least 95% while heating and/or while deforming and cooling.

15. The method according to claim 10, wherein the marking, as seen in plan view, is formed by a plurality of punctiform, island-shaped partial regions having a mean diameter of at most 50 m, wherein the marking, as seen in plan view and considered with all partial regions taken together, has a mean extent of at least 20 times the mean diameter, and wherein a mean roughness of a surface of the workpiece at the marking deviates from a mean roughness of remaining regions of the surface by at most a factor of 2.

16. The method according to claim 10, wherein the marking is formed by at least one continuous marking region, wherein the at least one marking region has a mean extent of at least 20 times a mean diameter of color pigments of the marking.

17. The method according to claim 10, further comprising applying, after deforming and cooling, at least one lacquer to the workpiece such that the lacquer completely covers the marking and the marking is no longer discernible to an observer through the lacquer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) A method described here and a workpiece described here are explained in greater detail below on the basis of exemplary embodiments with reference to the drawing. In this case, identical reference signs indicate identical elements in the individual figures. However, relations to scale are not illustrated; rather individual elements may be illustrated with an exaggerated size in order to afford a better understanding. In the figures:

(2) FIGS. 1A-1E show cross-sectional views of a method forming a deformed workpiece with markers and an lacquer disposed thereon according to embodiments,

(3) FIGS. 2A-2C show schematic sectional illustrations of markings located in undeformed regions of the finished workpiece according to,

(4) FIG. 3 shows a schematic sectional view of a plurality of continuous marking regions located on the workpiece according to embodiments,

(5) FIGS. 4A-4B show schematic plan views of a plurality of continuous marking regions according to embodiments, and

(6) FIGS. 5A-5C show schematic sectional views of applying and removing of markings to the workpiece according to embodiments.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

(7) FIG. 1A-1E illustrate one exemplary embodiment of a method for producing a workpiece. In accordance with FIG. 1A, a blank 2 is provided. The blank 2 is preferably a steel.

(8) Optionally, see FIG. 1B, a blank 2 is provided which comprises an anti-scaling protective layer 22, for instance, composed of an aluminum-silicon alloy. In order to simplify the illustration, the anti-scaling protective layer 22 is depicted only at one side of the blank 2. Furthermore, a thickness of the anti-scaling protective layer 22 is illustrated with an exaggerated size. Such anti-scaling protective layers 22 are preferably also present in all the other exemplary embodiments. In a departure from a subsequent illustrations, however, the blanks 2 can also each be free of an anti-scaling protective layer 22.

(9) In the method step in FIG. 1C, a marking 3 is applied to the anti-scaling protective layer 22, preferably at room temperature, for example, by printing. The marking 3 comprises color pigments, preferably ceramic particles or phosphor particles, whereby the marking 3 is distinguishable from the blank 2 by a reader or by an observer, as seen in plan view.

(10) Afterward, the blank 2 with the marking 3 is heated to a deformation temperature. The deformation temperature is approximately 930 C., for example.

(11) Subsequently, see FIG. 1D, the blank is deformed to form the workpiece 1. A metal body 11 arises in the process, said metal body determining the shape of the workpiece 1. The anti-scaling protective layer 22 is still situated on the metal body 11. Deforming to form the workpiece 1 makes it possible for the marking 3 to be intimately connected to the anti-scaling protective layer 22 or to the metal body 11. By way of example, the marking 3 is partly pressed and/or fused into the anti-scaling protective layer 22.

(12) Shaping to form the metal body 11 is preferably deep-drawing. In this case, the blank 2 previously brought to the deformation temperature is introduced into a cooled mold (not illustrated) and pressed, thus giving rise to the metal body 11. In this case, a deformation temperature is preferably higher than the melting points of the anti-scaling protective layer 22 and of the marking 3, wherein a melting point of the marking 3 is higher than a melting point of the anti-scaling protective layer 22. In the cooled mold, the marking 3 then solidifies before the anti-scaling protective layer 22, thereby preventing or greatly reducing running of the marking 3 during deep-drawing.

(13) In the optional method step in FIG. 1E, a lacquer 4 is subsequently applied to the marking 3 and to the anti-scaling protective layer 22.

(14) FIGS. 2A-2C illustrate exemplary embodiments of the finished workpieces 1, only undeformed regions of the workpieces 1 being illustrated in order to simplify the illustration. The marking 3, preferably also in all the other exemplary embodiments, is situated in regions of the workpiece 1 that are deformed little or are not deformed, thus simplifying later reading of the marking 3.

(15) FIGS. 2A-2C, the marking 3 is formed in each case by particles which comprise or consist of a phosphor 33, likewise in particle form. A mean diameter of the particles is, for example, between 0.7 m and 5 m inclusive. The particles of the marking 3, which differ optically from the anti-scaling protective layer 22, are preferably present only in a plane and not stacked one above another.

(16) In accordance with FIG. 2A, the particles of the marking 3 are applied on the anti-scaling protective layer 22 and are not or not significantly pressed into the anti-scaling protective layer 22. In other words, the marking is then elevated above the anti-scaling protective layer 22.

(17) In the case of the exemplary embodiment in FIG. 2B, the particles of the marking 3 are partly pressed and/or fused into the anti-scaling protective layer 22. In this case, a surface roughness of the anti-scaling protective layer 22 is of the same order of magnitude as a mean diameter of the particles of the marking 3. In other words, the marking 3 produces no or no significant difference in a surface roughness.

(18) FIG. 2C illustrates that the particles of the marking 3 at least partly penetrate through the anti-scaling protective layer 22 and are partly in contact with the metal body 11. In accordance with FIG. 2C, the particles of the marking 3 are largely integrated into the anti-scaling protective layer 22 and do not or not significantly project from the anti-scaling protective layer 22.

(19) FIG. 2C additionally shows that the particles of the marking 3 comprise a phosphor 33, likewise in particle form. The phosphor 33 is embedded into a matrix material 35. The matrix material 35 is preferably a glass. By means of the matrix material, the particles of the marking 3 adhere to the anti-scaling protective layer 22, such that the marking 3 does not detach from the anti-scaling protective layer 22 during intended use of the workpiece 1. At the deformation temperature, in particular only the matrix material 35 melts, and the phosphor 33 does not melt. Such a construction of the particles of the marking 3 composed of a matrix material 35 and composed of phosphor particles 33 can also be present in the configurations in FIGS. 2A and 2B.

(20) The individual particles of the marking 3 form partial regions 38 that are grouped. By virtue of the grouped partial regions 38, see FIG. 4A, the marking 3 is shaped, for example, as a bar code or as lettering.

(21) FIG. 3 shows that the marking is formed by a plurality of continuous marking regions 39, see also the plan view in FIG. 4B. A thickness of the marking regions 39 is, for example, at least 0.5 m and/or at most 25 m. In the marking regions 39, phosphor particles 33 can be present in a manner stacked one above another, said phosphor particles being embedded into the continuous matrix material 35.

(22) It is possible for the marking regions 39 to be partly pressed into the anti-scaling protective layer 22. Likewise, the marking regions 39 preferably have a reduced surface roughness compared with the anti-scaling protective layer 22, as illustrated schematically in FIG. 3.

(23) Also, analogously to FIGS. 2A and 2C, the marking regions 39 can be applied only on the anti-scaling protective layer 22 or extend as far as the metal body 11.

(24) FIGS. 5A-5C show a further exemplary embodiment of the production method. The step in accordance with FIG. 5A corresponds here to the step in accordance with FIG. 1C, according to which the marking 3 is applied to the optional anti-scaling protective layer 22. In this case, the marking 3 comprises the particles 33 composed of the phosphor, for instance, which are embedded into an organic matrix material 35. The step in accordance with FIG. 5A preferably takes place at room temperature.

(25) Afterward, the matrix material 35, which is an acrylic lacquer, in particular, is decarbonized during the heating of the blank 2 to the deformation temperature and/or during deep-drawing, such that only the phosphor particles 33 remain. In other words, the matrix material 35 preferably disappears without residue as a result of the elevated temperature during the production method.

(26) In accordance with FIG. 5B, only the phosphor particles 33 then remain at the anti-scaling protective layer 22, without the matrix material 35.

(27) Since the phosphor particles 33 are thus applied to the anti-scaling protective layer 22 without matrix material, it is possible, for example, directly before lacquering, not illustrated in FIGS. 5A-5C, to remove the phosphor particles 33, see FIG. 5C. The phosphor particles 33 are removed, for instance, by being wiped away with a dry cloth. In this case, the anti-scaling protective layer 22 and the metal body 11 remain intact.

(28) The invention described here is not restricted by the description on the basis of the exemplary embodiments. Rather, the invention encompasses any novel feature and also any combination of features, which in particular includes any combination of features in the patent claims, even if this feature or this combination itself is not explicitly specified in the patent claims or exemplary embodiments.