Abstract
The invention relates to a method for checking an aerosol-generating article for manufacturing defects, comprising: recording several 2-dimensional surface profiles of the aerosol-generating article while rotating the aerosol-generating article, combining several surface profiles recorded at different rotation angles to obtain a 3-dimensional surface profile, calculating a maximum height difference of the 3-dimensional surface profile, and rejecting the aerosol-generating article if the maximum height difference of its 3-dimensional surface profile is above a threshold value.
Claims
1-15. (canceled)
16. A method for checking an aerosol-generating article for manufacturing defects, comprising: recording several 2-dimensional surface profiles of the aerosol-generating article while rotating the aerosol-generating article, combining several surface profiles recorded at different rotation angles to obtain a 3-dimensional surface profile, calculating a maximum height difference of the 3-dimensional surface profile, and rejecting the aerosol-generating article if the maximum height difference of its 3-dimensional surface profile is above a threshold value, wherein additionally a 2-dimensional visual image of the surface of the aerosol-generating article is recorded while rotating the aerosol-generating article several 2-dimensional surface visual images or intensity lines recorded at different rotation angles are combined to obtain a combined 2-dimensional visual surface image, the combined visual surface image is compared with a combined defect-free visual image of a defect-free aerosol-generating article via image-correlation, and the aerosol-generating article is rejected if its combined visual surface image does not fit the defect-free visual image.
17. The according to claim 16, wherein the aerosol-generating article comprises a filter portion and a substrate portion, the substrate portion comprising aerosol-forming substrate, further wherein the aerosol-generating article comprises a tipping paper overwrapping the filter portion and at least a part of the substrate portion is adjacent to the filter portion.
18. The method according to claim 17, wherein several 2-dimensional surface profiles of at least the filter portion and parts of the substrate portion overwrapped by the tipping paper are recorded.
19. The method according to claim 16, wherein the manufacturing defects are selected from a group consisting of tears, slits, holes, wrinkles, breaking, faulty adhesion of filter portion to substrate portion, and exposed connection between filter portion and substrate portion.
20. The method according to claim 16, wherein at least one visual marker is present on the surface of the aerosol-generating article and wherein the position of the visual marker on the surface of the aerosol-generating article is determined using the combined 2-dimensional visual surface image, preferably wherein the visual marker comprises at least one line.
21. The method according to claim 16, wherein the manufacturing defects are selected from a group consisting of stains, displacement of the tipping paper relative to the substrate portion, mixing of different brands of aerosol-generating articles and folding of the tipping paper.
22. The method according to claim 16, wherein the aerosol-generating article is rotated 360 degrees and wherein one or both: a 360 degrees 3-dimensional surface profile, or a 360 degrees combined 2-dimensional visual surface image are obtained.
23. The method according to claim 16, wherein a line laser sensor is employed for recording one or both of: the several 2-dimensional surface profiles, or the several 2-dimensional surface visual images.
24. An inspection device configured for detection of manufacturing defects in aerosol-generating articles, comprising: a surface profile sensor configured for recording several 2-dimensional surface profiles of the aerosol-generating article, rotating means configured for rotating the aerosol-generating article during the recording of the surface profiles, and a surface profile controller configured for processing the several 2-dimensional surface profiles recorded at different rotation angles to obtain a 3-dimensional surface profile, and configured for calculating a maximum height difference of the 3-dimensional surface profile, further comprising: a visual imaging sensor configured for recording several 2-dimensional visual images or intensity lines of the surface of the aerosol-generating article while rotating the aerosol-generating article, and a visual imaging controller configured for processing the several 2-dimensional surface visual images or intensity lines at different rotation angles to obtain a combined 2-dimensional visual surface image and configured for comparing the combined visual surface image with a combined defect-free visual image of a defect-free aerosol-generating article via image-correlation.
25. The inspection device according to claim 24, wherein the visual imaging sensor and the surface profile sensor are integrated in one single sensor head, preferably wherein the sensor head is a line laser sensor head.
26. The inspection device according to claim 24, wherein the surface profile controller and the visual imaging controller are integrated into one single control unit.
27. The inspection device according to claim 24, wherein the rotating means comprises either: two rotating drums, one rotating drum and one stationary part, one moving belt and one stationary part.
28. The inspection device according to claim 24, and an aerosol-generating article.
Description
[0130] The invention will be further described, by way of example only, with reference to the accompanying drawings in which:
[0131] FIG. 1 shows a schematic, perspective view of an inspection device and an inspection system according to one embodiment of the invention;
[0132] FIG. 2 shows a schematic drawing of a 2-D/3-D laser profiler inspecting an aerosol-generating article between a first rotating drum and straps;
[0133] FIGS. 3A and 3B shows cross-sectional views of a 2-D/3-D laser profiler scanning an aerosol-generating article rotating between two rotating drums;
[0134] FIG. 4 depicts another schematic perspective drawing showing a moving 2-D/3-D profiler inspecting an aerosol-generating article rotating between a moving belt and straps;
[0135] FIGS. 5A and 5B show a photograph of defect-free double stick containing two aerosol-generating articles connected via the filter portion and one single 2-dimensional surface profile of that double stick, respectively;
[0136] FIGS. 6A and 6B show a photograph of a double stick containing two aerosol-generating articles including a manufacturing defect and one single 2-dimensional surface profile of that double stick, respectively;
[0137] FIG. 7 shows a 3-dimensional surface profile of an aerosol generating article including a manufacturing defect projected on a 2-dimensional plane;
[0138] FIGS. 8A and 8B show two different combined 2-dimensional visual surface images of two different aerosol-generating particles with manufacturing defects.
[0139] In the following the same elements are marked with the same reference numerals throughout all the figures.
[0140] FIG. 1 depicts an inspection device and an inspection system configured for detection of manufacturing defects in aerosol-generating articles according to one embodiment of the invention. The inspection device is preferably employed as so-called in-line quality inspection during the manufacturing process of the aerosol-generating articles. The inspection device comprises a laser sensor 12, in particular a 2-D/3-D laser profiler which includes a laser 12A and a sensor 12B integrated in one sensor head. The 2-D/3-D laser profiler scans the surface of an aerosol-generating article 10, or the surface of a so-called double stick 2?10, which contains two aerosol-generating articles, which are connected by a double filter portion connected on both sides to substrate portions. In the following, when we refer to the aerosol-generating article 10, this is similarly meant to include the double stick 2?10, if not mentioned otherwise. The 2-D/3-D laser profiler may be configured to record the several 2-dimensional surface profiles and the several 2-dimensional surface visual images of the aerosol-generating article or the double stick simultaneously. The aerosol-generating article is rotated between rotating means, a first rotating drum 14 and second rotating drum 16. The first rotating drum rotates in the direction indicated by the arrows 14A and the second rotating drum 16 rotates in an opposite direction indicated by the arrow 16A. This allows the 2-D/3-D laser profiler to scan large parts of the surface of the aerosol-generating article 10, preferably the complete surface of the aerosol-generating article in the case that the article is rotated by 360 degrees. During the scanning process the 2-D/3-D laser profiler is kept stationary. The first rotating drum 14 includes protrusions 14B which are able to transport the aerosol-generating article 10 further through the manufacturing process. Initially, the aerosol-generating article 10 is kept in place on the first rotating drum 14 via vacuum holes 14C. Once an aerosol-generating article held by the vacuum holes 14C reaches the second rotating drum 16, the article starts rotating and inspection of the article by the 2-D/3-D laser profiler begins. Inspection of the aerosol-generating article comes to an end when the next protrusion 14B of the first rotating drum 14 pushes the aerosol-generating article 10 away from the second rotating drum 16. Thus, an aerosol-generating article 10 is rotated between the first rotating drum and second rotating between adjacent protrusions 14B of the first rotating drum 14. The first and the second rotating drums 14 and 16 and the 2-D/3-D laser profiler are connected via communication connections 22 to a control unit 18. The control unit 18 is configured to process one or both of either the several two-dimensional surface visual images or the several intensity lines and several two-dimensional surface profiles. In particular, the control unit 18 may be configured to combine either the several two-dimensional surface visual images or the several intensity lines to obtain combined-dimensional visual surface image. Similarly, the control unit 18 may be configured to combine several two-dimensional surface profiles in order to obtain 3-dimensional surface profile. A workstation 20 is present, connected to the control unit 18 via a communication connection 22. The workstation 20 allows the user to handle the inspection device. Such an inspection device is configured to provide an in-line inspection of the manufactured aerosol-generating articles during the manufacturing process. This in-line inspection allows for the detection of various different manufacturing defects, which either can be detected preferably by visual imaging or surface profiling. This inspection device therefore allows the user to carry out the method for checking for manufacturing defects of the present invention in an automated way.
[0141] FIG. 2 depicts another embodiment of rotating means for the inspection device, which may be integrated into the inspection device of FIG. 1 instead of the two rotating drums. In this embodiment the rotating means include a first rotating drum 14 and straps 24, which secure the aerosol-generating article 10 to the rotating drum. In this case, the 2-D/3-D laser profiler 12 including the laser 12A and the sensor 12B has to move together with the first drum, in order to inspect different parts of the surface of the aerosol-generating article.
[0142] FIG. 3A depicts two rotating drums 14 and 16, rotating in opposite directions as rotating means in a cross-sectional view. FIG. 3B shows a cross-sectional view of the different, subsequent steps of transporting the aerosol-generating article 10 with the two rotating drums 14 and 16. In the first step denoted with a) the aerosol-generating article 10, which is held in place by the vacuum holes of the first rotating drum 14 gets caught between drums 14 and 16 and starts rotating (vacuum holes not shown in FIG. 3B). During the rotation the 2-D/3-D laser profiler scans the surface of the aerosol-generating article as shown in the second step denoted with b) (only beams 12A and 12B of the laser profiler are shown). In the final step denoted with c) the next protrusion 14B of the first rotating drum 14 picks up the aerosol-generating article 10, thereby terminating the inspection of the aerosol-generating article in order to transport it further through the manufacturing process.
[0143] FIG. 4 depicts a perspective schematic view of another embodiment of rotating means, which can be incorporated into the inspection device shown in FIG. 1. In this case, the aerosol-generating article 10 is secured between the moving belt 26 and straps 24. Since the straps 24 are stationary part of the device, the aerosol-generating article 10 starts rotating between the stationary straps 24 and the moving belt 26 and at the same time is moved in the direction indicated by the arrow 15 (roto-translation of the aerosol-generating article). In order to scan all or a large part of the surface of the aerosol-generating article, the 2-D/3-D profiler 12 has to follow the translation of the aerosol-generating article indicated by the arrow 15.
[0144] FIG. 5A shows a photograph of a double stick 2?10, which includes two substrate portions 10B, which are connected to one double filter portion 10A by tipping paper. The dashed line in FIG. 5A indicates the cut line for cutting the double stick in order to produce two single aerosol-generating articles 10. In this case, the double stick does not contain any manufacturing defects. One continuous first visual marker 10C is present on the double stick, which is a line running around the circumference of the double stick. Furthermore, a set of second visual markers 10D is present on the tipping paper of the double stick. The first and the set of second visual markers can be used in order to monitor the correct position of the tipping paper, when connecting the double filter portion 10A to both substrate portions 10B.
[0145] FIG. 5B shows one single two-dimensional surface profile of the double stick shown in FIG. 5A. Since no defects are present in this double stick, the two-dimensional surface profile is even and does not show any great protrusions above the threshold level.
[0146] FIG. 6A shows a photograph of another double stick 2?10, which includes a manufacturing defect 30. In particular, the tipping paper has been delaminated from the double stick and protrudes from the double stick.
[0147] FIG. 6B shows a single 2-dimensional surface profile 28 of the double stick shown in FIG. 6A in the region, where the manufacturing defect 30 is present. The protrusions 30 of the manufacturing defect are clearly visible in the 2-dimensional surface profile 28. Therefore, recording 2-dimensional surface profiles and combining them to a 3-dimensional surface profile is particularly suitable in order to detect manufacturing defects which involve changes in the surface profile of the double stick.
[0148] FIG. 7 shows a 2-dimensional projection 32 of a 3-dimensional surface profile. Several 2-dimensional surface profiles 28 are aligned one above the other. Adjacent surface profiles 28 are separated by the so-called step size 34, which are equidistant rotation angles. One single 2-dimensional surface profile 28 is indicated by a single bright line in FIG. 7. For the sake of clarity only a few of the bright lines are marked with the reference numeral 28. Manufacturing defect 30 is clearly visible in the 3-dimensional surface profile 32.
[0149] FIGS. 8A and 8B show different combined 2-dimensional visual surface images of double sticks with manufacturing defects. Such a grayscale surface image can be obtained by combining various different grayscale intensity lines, recorded at different rotation angles of the aerosol-generating article. In FIG. 8A the set of second visual markers 10D are not straight, but wavy as shown in the circles denoted with 38 probably due to dislocation of the tipping paper in this region. In FIG. 8B a stain 40 is present as a manufacturing defect. In both cases, the visual imaging of the double stick is well able to detect both manufacturing defects.
