METHOD AND DEVICE FOR PRODUCING AND INSPECTING A PACKAGE

Abstract

A method for producing and inspecting a package comprising at least one product cavity of a formed part sealed by a lidding film comprises the steps of: (a) sealing the lidding film to the formed part along a seam by means of a sealing device, which comprises a sealing contour with a plurality of segments; (b) detecting, by means of the sealing device, a parameter characteristic of the sealing quality of the seam in each segment; and (c) detecting a problem with the sealing according to step (a) based on the parameter detected according to step (b) in each segment.

Claims

1. A method for producing and inspecting a package comprising at least one product cavity in a formed part sealed by a lidding film, wherein the method comprises the steps of: (a) sealing the lidding film to the formed part along a seam, which surrounds the at least one product cavity, by means of a sealing device comprising a sealing contour, which is divided into a plurality of segments; and (b) detecting, by way of the sealing device, a parameter characteristic of a sealing quality of the seam in each segment of the plurality of segments along the seam, (c) detecting a problem with the sealing according to step (a) based on the parameter detected according to step (b) in each segment of the plurality of segments.

2. The method according to claim 1, wherein the problem with the sealing detected according to step (c) is a problem of the seam or a problem of the sealing device.

3. The method according to claim 1, wherein step (b) comprises detecting an actual value of the parameter in each segment of the plurality of segments, and wherein step (c) comprises the steps of: (c1) comparing the detected actual value of the parameter of each segment of the plurality of segments with a nominal value of the parameter defined for each segment of the plurality of segments; (c2) determining, for each segment of the plurality segments, whether there is a deviation between the actual value and the nominal value of the parameter; and (c3) detecting the problem with the sealing according to step (a) based on the deviation between the actual value and the nominal value of the parameter determined according to step (c2).

4. The method according to claim 1, wherein the seam around the product cavity comprises a length which is between 25 mm and 600 mm.

5. The method according to claim 1, wherein the plurality of segments of the sealing contour comprises at least four segments.

6. The method according to claim 1, wherein the sealing contour is substantially ring-shaped.

7. The method according to claim 1, wherein the segments of the plurality of segments are arranged adjacent to each other, and wherein the segments of the plurality of segments are arranged continuously along the sealing contour, wherein step (b) is carried out along the entire seam.

8. The method according to claim 1, wherein the sealing device comprises a plurality of heating elements and a plurality of sensor elements, wherein one heating element of the plurality of heating elements and one sensor element of the plurality of sensor elements are assigned to each segment of the plurality of segments, wherein operating data of the plurality of heating elements and/or of the plurality of sensor elements is used to detect the parameter according to step (b).

9. The method according to claim 1, wherein the parameter characteristic of the sealing quality is a temperature, and wherein the sealing device, according to step (b), detects the temperature in each segment of the plurality of segments along the seam.

10. The method according to claim 1, wherein the parameter characteristic of the sealing quality is a power demand of each of the plurality of segments during the sealing according to step (a), and wherein the sealing device, according to step (b), detects the power demand of each segment of the plurality of segments along the seam.

11. The method according to claim 3, wherein the nominal value of the parameter is a predetermined value.

12. The method according to claim 3, wherein step (c1) further comprises the step of determining at least one comparison value based on the actual values of the parameter of at least some of the plurality of segments, and wherein the nominal value of the parameter corresponds to the comparison value.

13. The method according to claim 1, wherein, after step (c), the method further comprises the step of determining a quality of the seam as a function of the problem detected according to step (c).

14. The method according to claim 3, wherein step (c2) further comprises the step of determining an extent of the deviation, and wherein, after step (c), the method further comprises the step of assigning the package to a category of at least a first and a second category as a function of the determined extent of the deviation, wherein each category is characteristic of a specific quality of the seam.

15. The method according to claim 14, wherein, after assigning the package to a category, the method further comprises the step of: processing the package depending on the category to which the package has been assigned, wherein the processing is different for each category.

16. A sealing device for sealing in a sealing operation a lidding film to a formed part having at least one product cavity, wherein the sealing device comprises: a sealing contour for producing a seam, wherein the sealing contour is divided into a plurality of segments; a plurality of heating elements and a plurality of sensor elements, wherein one heating element of the plurality of heating elements and one sensor element of the plurality of sensor elements are assigned to each segment of the plurality of segments; and a control unit; wherein the sealing device is configured to detect a parameter characteristic of the sealing quality of the seam in each segment of the plurality of segments by way of the plurality of sensor elements and/or the plurality or heating elements; wherein the control unit is configured to detect a problem with the sealing operation based on the parameter.

17. The sealing device according to claim 16, wherein the problem with the sealing operation is a problem of the seam or a problem of the sealing device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0067] FIG. 1 shows a perspective view of an embodiment of a sealing device for producing and inspecting a package;

[0068] FIG. 2 shows a schematic side view of part of the sealing device according to FIG. 1;

[0069] FIG. 3 shows a schematic top view of the sealing device according to FIG. 1;

[0070] FIGS. 4a and 4b show perspective views of examples of a package with and without a lidding film;

[0071] FIGS. 5 and 6 show top views of a formed part of the package according to FIG. 4; and

[0072] FIGS. 7a-c show flow charts of a method for producing and inspecting a package.

DETAILED DESCRIPTION

[0073] FIG. 1 shows a perspective view of an embodiment of a sealing device 2. The sealing device 2 comprises a sealing contour 4, which is configured to come into contact with a lidding film of a package to be sealed (see FIG. 4). For heat-sealing the lidding film to a formed part of the package to be sealed, the sealing device 2 comprises a heater 6, which heats the sealing contour 4 and is thus in thermally conductive contact with the sealing contour 4. The heater 6 can be connected by means of an insulating body 8 of the sealing device 2 to a housing 10 of the sealing device 2. The insulating body 8 insulates the housing 10, the components accommodated therein, and the rest of the sealing device 2 thermally from the heater 6, so that the heat it generates is conducted effectively to the sealing contour 4.

[0074] A control unit 12 for the open-loop and/or closed-loop control of the sealing device 2 can be accommodated in the housing 10, for example. The control unit 12 is connected to the heater 6. The control unit 12 and the heater 6 can be supplied with power and possibly other control signals by way of a terminal 13. It is also conceivable that the control unit 12 could be provided outside the housing 10 and that the control signals could be transmitted to the heater 6 over an appropriate line connected to the terminal 13 or wirelessly.

[0075] As shown in FIG. 1, the sealing contour 4 is substantially ring-shaped and encloses a central area 14, in which the sealing device 2 does not have a sealing contour 4. The sealing contour 4 preferably has a shape which corresponds substantially to the shape of a seam to be produced (see FIGS. 3-6), as a result of which the heat input from the sealing device 2 can be effectively directed and concentrated to the area of the desired seam. The sealing contour 4 can project beyond other components and areas, in particular beyond the central area 14. In the embodiment shown, this is achieved in that the sealing contour 4 comprises a protective layer 16, which protects the heater 6 and is made of a material having good thermal conductivity. The sealing contour 4, however, can also be configured as an integral part of the heater 6, which then has a corresponding profile.

[0076] The sealing device 2 may further comprise at least one suction opening 18 for drawing up the lidding film, thereby enabling the sealing device 2 to arrange the lidding film on the formed part prior to sealing. Here, the sealing device 2 comprises a plurality of such suction openings 18, which are connected to a source of negative pressure, such as a vacuum pump, by way of an appropriate connector 20 on the housing 10 and which are arranged within the sealing contour 4 in the central area 14 of the sealing device 2.

[0077] In one embodiment, the sealing device 2 may be configured to seal a plurality of packages or one package having a plurality of product cavities and seams at the same time. In this case, the sealing device 2 comprises a plurality of sealing contours 4 corresponding to the number of product cavities, as indicated in FIG. 1 by the housings 10′ and 10″ shown in broken line by way of example, on each of which a sealing contour and a heater configured analogously to that of the previously described sealing device 2 are provided.

[0078] FIGS. 2 and 3 show details of the sealing device 2, in particular of the heater 6. The sealing device 2, namely the heater 6 of the sealing device, preferably comprises a plurality of heating elements 22 for heating the sealing contour 4. The sealing device 2 may further comprise a plurality of sensor elements 24, which are preferably configured to detect the temperature of the heating elements 22 and/or of the sealing contour 4. The plurality of heating elements 22 and the plurality of sensor elements 24 can be configured as strip conductors, respectively, but may also be formed by wires. The plurality of heating elements 22 and the plurality of sensor elements 24 may be applied to a carrier substrate 26. For example, the strip conductors could be printed on a side of the carrier substrate 26 facing the lidding film, i.e., the side of the carrier substrate 26 facing away from the insulating body 8. The carrier substrate 26 is preferably made of ceramic material. As a result, a highly dynamic heater 6 with effective local control is provided. The protective layer 16 can cover the plurality of heating elements 22 and the plurality of sensor elements 24 to protect them from wear, as shown in FIG. 2. In the top view according to FIG. 3, the sealing contour 4 and protective layer 16 are shown only partially, in dashed line, so that the heating elements 22 can be seen more clearly.

[0079] In the embodiment according to FIG. 2, the heating elements 22 of the plurality of heating elements 22 are formed separately from the sensor elements 24 of the plurality of sensor elements 24, e.g., by separate wires, strip conductors, or sensors.

[0080] In the embodiment according to FIG. 3, one heating element 22 and one sensor element 24 are configured as an integral unit, here, for example, as a single strip conductor. That is, each of the plurality of heating elements 22 is combined with one of the plurality of sensor elements 24 in an integral element. This can be achieved, for example, in that the plurality of heating elements 22 are electrical resistance heaters. Consequently, their resistance changes as a function of temperature, the temperature thus being detectable based on the resistance of the heating element 22. Unless otherwise described, either of the two embodiments can be used as desired and combined with any of the other features of the sealing device described herein.

[0081] As can be seen from a consideration of FIGS. 1 and 3 together, the sealing contour 4 is divided into a plurality of segments 28. In the exemplary embodiment shown in FIG. 3, the plurality of segments 28 comprises eight segments 28a, 28b, 28c, 28d, 28e, 28f, 28g, 28h. The sealing contour 4 does not have to be divided structurally into segments 28a-h. For example, the sealing contour 4 can, as shown, be divided “imaginary” into segments 28a-h in correspondence with the arrangement of the plurality of heating elements 22, so that each segment 28a-h comprises one heating element 22 of the plurality of heating elements 22 and preferably one sensor element 24 of the plurality of sensor elements 24. The segments 28a-h preferably are arranged directly adjacent to each other and continuously along the sealing contour 4. Each heating element 22 heats a corresponding segment 28a-h of the sealing contour 4 assigned to it, and each sensor element 24 monitors a corresponding segment 28a-h of the sealing contour 4 assigned to it, in particular its temperature. As a result, each segment 28a-h of the plurality of segments 28 can be actuated and monitored individually.

[0082] FIGS. 4a and 4b show perspective views of a package 30, which can be produced by means of the sealing device 2 and method described herein. The package 30 comprises a formed part 32, in which a product cavity 34 has been formed, and a lidding film 36, which is sealed to the formed part 32. For the sake of illustration and clarity, the lidding film 32 is shown only in FIG. 4b, whereas, in FIG. 4a, it has been omitted to reveal the features underneath. The formed part 32 can be an injection-molded part, as used, for example, for the packaging of contact lenses, or it may be a blister pack, as used, for example, for the packaging of pharmaceutical products. The product cavity 34 is preferably configured as a pocket in the formed part 32 and preferably receives a product and/or a fluid (not shown). The formed part 32 preferably comprises a flange 38, which surrounds the product cavity 34 and contacts the lidding film 36. The lidding film 36 is sealed to the formed part 32 along a seam 40, which surrounds the product cavity 34. For this purpose, the flange 38 may provide a sealing surface, on which the seam 40 is formed.

[0083] FIGS. 5 and 6 show top views of the formed part 32 of the package 30, wherein, for the sake of illustrating the seam 40 surrounding the product cavity 34, the lidding film 36, which is sealed to the formed part 32 along the seam 40, is omitted. Here it is particularly easy to see that the seam 40 completely surrounds the product cavity 34 to seal the product cavity 34 in leakproof fashion. As can be derived from FIGS. 3 and 5 in combination, the seam 40 and the sealing contour 4 of the sealing device 2 preferably have a corresponding shape, so that the sealing area is heated effectively and the seam 40 is produced all the way around the product cavity 34.

[0084] For the sake of a better understanding, the seam 40 in FIGS. 5 and 6 is divided into a plurality of sections 42a-h, each of which preferably corresponds in size and shape to one of the segments 28a-h of the plurality of segments 28. Thus a section 42a-h of the seam 40 is associated with each segment 28a-h of the sealing contour 4.

[0085] As an example of a potential problem of the sealing operation and a resulting defect of the seam 40, FIG. 6 shows a contaminant 44 in the area of the seam 40 (also referred to as area of the sealing area or sealing surface). Here the contaminant 44 is located in section 42h of the seam 40 to be formed, which can be assigned to the segment 28h of the plurality of segments 28. The contaminant 44 can, for example, result from the process of filling the product cavity 34, e.g. when a product or a part of it is not completely accommodated in the product cavity 34, or when a droplet of a fluid to be filled in the product cavity 34 finds its way onto the sealing surface. The contaminant 44 may result in the lidding film 36 not being sealed properly to the formed part 32 at the location of the contaminant 44. Therefore, no seam 40 at all or only an incomplete seam may be created at the location of the contaminant 44.

[0086] A method for producing and inspecting the package 30 as described below with reference to FIGS. 7a-c is particularly suitable for detecting problems with the sealing operation, in particular of problems resulting in an incomplete or otherwise defective seam. The steps of such method do not have to be carried out one after the other but some of them may be performed simultaneously, as will be evident from the description.

[0087] The method comprises, first, the step of sealing of the lidding film 36 to the formed part 32 along the seam 40, which surrounds the at least one product cavity 34, by means of the sealing device 2 (step (a)). The sealing device 2 comprises the sealing contour 4, which is divided into the plurality of segments 28. The sealing device 2 is preferably configured according to the embodiments described with reference to FIGS. 1-3. The sealing according to step (a) may be performed thermally, so that the package 30 which is produced is a heat-sealed plastic package such as, for example, a blister pack for pharmaceuticals or a contact lens package. The sealing operation is preferably carried out under the application of pressure and heat to the lidding film 36 and the formed part 32 in the area of the seam 40 to be produced, as is familiar to the skilled person for the production of packages of this type.

[0088] The method further comprises step (b) of detecting, by means of the sealing device 2, a parameter P, which is characteristic of a sealing quality of the seam 40, in each segment 28a-h of the plurality of segments 28 around the seam 40. For each of the plurality of segments 28, the parameter P may be, for example, an electrical resistance R of the associated heating and/or sensor element 22, 24, a temperature T of the associated heating and/or sensor element 22, 24 or of the corresponding segment 28a-h, or a power demand E of the segment 28a-h during the sealing according to step (a). The power demand but also the other parameters P, as described above, provide data on the sealing quality of the seam 40. To detect the parameter P, operating data of the plurality of heating elements 22 and/or of the plurality of sensor elements 24 can be used. The parameter P can be detected by means of the plurality of heating elements 22 and/or the plurality of sensor elements 24 and the control unit 12. It is particularly preferred in step (b) that an actual value P.sub.actual of the parameter P be detected.

[0089] Step (c) of the method comprises detecting a problem with the sealing operation according to step (a), in particular a problem with the seam 40 or with the sealing device 2, based on the parameter P detected in each segment 28a-h of the plurality of segments 28 according to step (b). A problem with the seam 40 can, for example, be caused by the contaminant 44 on the sealing surface (see FIG. 6). A problem with the sealing device 2 can be, for example, caused by a defective heating element 22.

[0090] It can thus be determined in a simple, quick, and accurate way whether the sealing operation according to step (a) has been executed properly in each segment 28a-h of the sealing contour 4, i.e., in each section 42a-h of the seam 40, and thus whether the seam 40 can satisfy the necessary quality requirements. It is possible to respond immediately, during the production process itself, to a failure or defect resulting from problems such as these.

[0091] In a preferred embodiment, the step of detecting a problem with the sealing operation comprises comparing the detected actual value P.sub.actual of the parameter P of each segment 28a-h of the plurality of segments 28 with a nominal value P.sub.nominal of the parameter P defined for each segment 28a-h (step (c1)) and determining, for each segment 28a-h of the plurality of segments 28, whether or not there is a deviation ΔP between the actual value P.sub.actual and the nominal value P.sub.nominal of the parameter P (step (c2)). The detection of a problem (step (c3)) with the sealing operation according to step (a) is then based on the deviation ΔP between the actual value P.sub.actual and the nominal value P.sub.nominal of the parameter P determined according to step (c2). If there is no deviation, it can be assumed that the sealing operation has been carried out properly.

[0092] The nominal value P.sub.nominal may be a predetermined value, which is retrieved by the control unit 12 and used for steps (c1) and (c2). As shown in FIG. 7b, step (c1) can alternatively comprise the step of determining a comparison value V based on the actual values P.sub.actual of the parameter P of at least some of the plurality of segments 28 (step (c1.1)) and using the comparison value V as the nominal value P.sub.nominal (step (c1.2)), which is then compared in step (c1.3) with the actual value P.sub.actual of a segment.

[0093] The method may further comprise the step of determining, in step (d), a quality Q of the seam 40 as a function of the problem detected according to step (c). A plurality of categories K may be defined for the packages to be produced, wherein each category K has been assigned to a specific quality Q of the seam 40 (step (d1)). As shown in FIG. 7c, it is preferred that step (c2) comprises the determination of an extent of the deviation ΔP, and that, after step (c), the method comprises the step of assigning the package 30 to a category K of at least a first category K1 and a second category K2, as a function of the determined extent of the deviation ΔP (step (d2)). Thus the package 30 can, for example, be assigned to the first category K1 “OK”, to the second category K2 “not OK but usable”, or to a third category K3 “Not OK, not usable”. Of course, a categorization can also be performed if only the presence of a deviation is determined (step (c2)) rather than the extent of a deviation. For example, the first category K1 may then correspond to the feature “no deviation” and the second category to the feature “deviation”.

[0094] Finally, the package 30, after having been assigned to a category K, can be processed further depending on the category K to which it has been assigned to (step (e)), wherein the processing according to step (e) is different for each category K. According to the embodiment of FIG. 7c, packages 30 of the first category K1, for example, may be packaged in an outer packaging (step (e1)), whereas packages 30 of the second category K2 and possibly of the third category K3 may be ejected from the process (step (e2)) and subjected separately to further processing or destroyed.

[0095] On the basis of the detailed description of the embodiments contained herein, the skilled person will be able to derive additional embodiments of the sealing device and of the method.