Method for checking an aerosol-generating article for manufacturing defects

1 . 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.

2 . The according to claim 1 , 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.

3 . The method according to claim 2 , 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.

4 . The method according to claim 1 , 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.

5 . The method according to claim 1 , 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.

6 . The method according to claim 1 , 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.

7 . The method according to claim 1 , 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.

8 . The method according to claim 1 , 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.

9 . 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.

10 . The inspection device according to claim 9 , 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.

11 . The inspection device according to claim 9 , wherein the surface profile controller and the visual imaging controller are integrated into one single control unit.

12 . The inspection device according to claim 9 , wherein the rotating means comprises either:

two rotating drums,

one rotating drum and one stationary part,

one moving belt and one stationary part.

13 . The inspection device according to claim 9 , and an aerosol-generating article.