Technical Field

The invention relates to packaging technology. More particularly, it is related to a method for evaluating the quality of a longitudinal sealing of a food package and an apparatus thereof.

Background Art

Today, within the food industry, an essential part of a food product is the packaging. Apart from branding of the product and presenting the customers with information the package also has an important role of ensuring the food safety. The packaging materials used in the package can be designed to provide strength and stability, so that the packages are not damaged during transportation. Furthermore, the packaging materials can form a protected environment for the food product so that it is protected from for example bacteria, germs, oxygen and sun light. However, the packaging material is not the only thing that is important in the package. The package needs also to be sealed properly. In a roll-fed system this is usually made by forming a longitudinal sealing along an overlap between two ends of the packaging material such that a tube is formed and thereafter forming packages from the tube by making transversal sealings in a lower end of the tube.

Ensuring the quality of the longitudinal sealing of a food package is not an easy task. Today, a common way of doing this is to evaluate batches of the finished products manually. This means opening finished product to assess the sealing. However this leads to waste of product and to guarantee the quality large quantities of packages must assessed. It is therefore need for an improved method for evaluating the quality of the longitudinal sealing in food packages.

Summary

It is an object of the invention to at least partly overcome one or more of the above-identified limitations of the prior art. In particular, it is an object to provide a method and apparatus thereof for assessing the quality of a longitudinal sealing in a food package.

It has been realized that by analysing image data of the longitudinal sealing in the processing line, the sealing can be continuously monitored and actions can be taken at an early stage. This leads to a reduction of wasted product and the quality of each package can be assured as opposed to today’s methods.

According to a first aspect it is provided a method for assessing quality of a longitudinal sealing in a roll fed packaging machine comprising a packaging material receiver arranged to receive a web of packaging material, wherein the packaging material may comprise an outer protective layer, an inner protective layer and an intermediate strengthening layer, and wherein the web may have a first and second longitudinal side section, a strip receiver arranged to receive a protective strip, wherein the protective strip may have a first and a second longitudinal side section, a strip applicator arranged to form a longitudinal strip sealing by applying the protective strip on the web by heating the web and the protective strip and pressing the web and protective strip together, a strip application camera arranged to capture strip application image data from a strip application area, said method comprising, receiving strip application image data of the strip application area, extracting features from the strip application image data, wherein the features may be related to effects of the heating provided by the strip applicator, determining a strip application status by evaluating the features, wherein the strip application status may relate to the quality of the longitudinal strip sealing, transmitting the strip application status, thereby providing a quality assessment of the longitudinal strip sealing.

Image data may be interpreted as either still images or a sequence of still images or a video sequence.

An advantage of the proposed method may be that the quality check can be made in-line as a part of the packaging machine. The transmitted status may give indication of whether the process needs to be interrupted or adjusted due to a low quality sealing, thereby reducing the risk of wasted product.

Optionally, the method may further comprise, receiving the web of packaging material by the packaging material receiver, receiving the protective strip by the strip receiver, forming the longitudinal strip sealing by the strip applicator, capturing the strip application image data from the strip application area by the strip application camera. The first longitudinal side section of the protective strip may be applied on the first longitudinal side section of the web, such that the second longitudinal section of the protective strip extends outside the web.

Optionally, the roll fed packaging machine may further comprise, a tube forming device arranged to form a tube of the web, such that the second longitudinal side section of the web partly overlap the first longitudinal side section of the web, attach the first and second longitudinal side sections of the web, and form a longitudinal tube sealing by applying the protective strip on the web, a tube forming camera arranged to capture tube forming image data from a tube forming area. Further, the method may further comprise, receiving tube forming image data of the tube forming area, extracting features from the tube forming image data, wherein the features may be related to effects of the heating provided by the tube forming device, determining a tube forming status of the longitudinal tube sealing by evaluating the features, wherein the tube forming status may be related to the quality of the longitudinal tube sealing, and transmitting the tube forming status, thereby acquiring a quality assessment of the longitudinal tube sealing.

A longitudinal sealing should be understood as a general term that may refer to either a longitudinal strip sealing, a longitudinal tube sealing or both. Similarly, a sealing status may refer to either a strip application status, a tube forming status or both.

Optionally, the method may further comprise, forming the tube of the web of packaging material by the tube forming device, attaching, the first and second longitudinal side sections of the web by the tube forming device, forming the longitudinal tube sealing by the tube forming device, capturing the tube forming image data from the tube forming area by the tube forming camera.

The second longitudinal side section of the protective strip may be applied on the second longitudinal side section of the web, such that the protective strip covers the intermediate layer of the packaging material that are exposed at the first longitudinal side section of the web.

The strip application image data and/or the tube forming image data may be captured through a polarized filter. The polarized filter(s) may be advantageous in that reflections in the surface the camera is capturing may be reduced. Furthermore, a heat pattern may be more clearly visible.

The transmitted status may be any one of the statuses underheating, normal or overheating. The status underheating may indicate that not enough heat has been provided when forming the longitudinal sealing. On the contrary, the status overheating may indicate that too much heat has been provided. The status normal may indicate that the longitudinal sealing is within acceptable quality.

The status may be transmitted to a control unit of the strip applicator and/or the tube forming device, and adjusting the heating power based on the status. This may be advantageous in that the roll fed packaging machine may adjust the heating automatically.

The status may be determined by providing the extracted features as input to an artificial intelligence model. The status may refer to the strip application status and/or the tube forming status. Artificial intelligence model should be understood as comprising e.g. machine learning models and neural networks.

Optionally, the step of extracting features from the strip application area may further comprise, identifying an overlapping area, a heat affected protective strip area and a heat affected web area of the strip application area and including these as the features from the strip application image data.

It should be understood that other features that may be useful for defining the quality of a strip may also be used.

The effects of the heating may comprise a number of cracks in the longitudinal sealing, a size of an overlapping area and reflective properties of the longitudinal sealing.

According to a second aspect it is provided a server for assessing quality of a longitudinal sealing in a roll fed packaging machine, said server may comprise a transceiver, a memory and a control unit, wherein the transceiver may be configured to execute a strip application image data receiver arranged to receive strip application image data of the strip application area, a strip application status transmitter arranged to transmit the strip application status, thereby providing a quality assessment of the longitudinal strip sealing, wherein the memory may comprise, a strip application image data processing module arranged to extract features from the strip application image data, wherein the features may be related to effects of the heating provided by the strip applicator, a strip application status module arranged to determine a strip application status by evaluating the features, wherein the strip application status may relate to the quality of the longitudinal strip sealing, wherein the control unit may be configured to execute the modules stored in the memory.

The strip application status module may determine the strip application status by providing the extracted features to an artificial intelligence model.

The transceiver may further comprise, a tube forming image data receiver arranged to receive tube forming image data of the tube forming area, a tube forming status transmitter arranged to transmit the tube forming status, thereby providing a quality assessment of the longitudinal tube sealing,

The memory may further comprise, a tube forming image data processing module arranged to extract features from the tube forming image data, wherein the features may be related to effects of the heating provided by the tube forming device, a tube forming status module arranged to determine a tube forming status of the longitudinal tube sealing by evaluating the features, wherein the tube forming status may be related to the quality of the longitudinal tube sealing.

According to a third aspect it is provided a system for assessing quality of a longitudinal sealing in a roll fed packaging machine, said system may comprise, a server according to the second aspect, one or more roll fed packaging machines which may comprise a packaging material receiver arranged to receive a web of packaging material, wherein the packaging material may comprise an outer protective layer, an inner protective layer and an intermediate strengthening layer, and wherein the web may have a first and second longitudinal side section, a strip receiver arranged to receive a protective strip, wherein the protective strip may have a first and a second longitudinal side section, a strip applicator arranged to form a longitudinal strip sealing by applying the protective strip on the web by heating the web and the protective strip and pressing the web and protective strip together, a strip application camera arranged to capture strip application image data from a strip application area, wherein the one or more roll fed packaging machines may be communicatively connected to the server.

Optionally, the roll fed packaging machine may further comprise, a tube forming device arranged to form a tube of the web, such that the second longitudinal side section of the web partly overlap the first longitudinal side section of the web, attach the first and second longitudinal side sections of the web, and form a longitudinal tube sealing by applying the protective strip on the web, a tube forming camera arranged to capture tube forming image data from a tube forming area.

Having a server communicatively connected to multiple roll fed packaging machines may be advantageous in that an artificial intelligence model used for determining the statuses may be provided with more data so that it may continuously improve. Put differently, the artificial intelligence model may learn from the image data provided by multiple roll fed packaging machines.

Still other objectives, features, aspects and advantages of the invention will appear from the following detailed description as well as from the drawings. The same features and advantages described with respect to one aspect are applicable to the other aspects unless explicitly stated otherwise.

Brief Description of the Drawings

Embodiments of the invention will now be described, by way of example, with reference to the accompanying schematic drawings, in which

Fig. 1 illustrates a simplified view of a packaging line enabled for assessing longitudinal sealing quality.

Fig. 2 is a cross-sectional view of an overlapping area of a packaging material.

Fig. 3a illustrates a protective strip and a web of packaging material in a topview.

Fig. 3b is another illustration of the protective strip and the web of packaging material in top-view

Fig. 4 illustrates a longitudinal sealing in a tube formed by the web of packaging material.

Fig. 5a illustrates, in top view, a strip applicator applying the protective strip to the web of packaging material. Fig. 5b illustrates, in side view, the strip applicator applying the protective strip to the web of packaging material.

Fig. 6a to fig. 6h are images of longitudinal strip sealings of different quality.

Fig. 7 is a flowchart illustrating the steps of a method for assessing quality of a longitudinal strip.

Fig. 8 is a schematic view of a server for assessing quality of a longitudinal sealing.

Fig. 9 is a schematic view of a system for assessing quality of a longitudinal sealing.

Detailed description

Fig. 1 illustrates a simplified view of a roll fed packaging machine 100, enabled for assessing quality of a longitudinal sealing 402, 502. The packaging material 202 can be provided on a roll of packaging material 102. A web of packaging material 104 can be provided to a strip applicator 122. The strip applicator 122 can further be provided with a protective strip 106. The strip applicator 122 can apply the protective strip 106 on the web 104 thereby forming a longitudinal strip sealing 502. The strip applicator 122 is described in more detail in connection to Fig. 5a and Fig. 5b. A strip application camera 108 can be provided to capture strip application image data from a strip application area 310. A polarized filter 116a may be provided in front of the strip application camera 108 such that the strip application image data is captured through the polarized filter 116a. The strip application image data can depict the longitudinal strip sealing 502 between the protective strip 106 and web 104. It can be in the form of a image, a sequence of images or a video sequence. From the strip application image data a status of the longitudinal strip sealing 502 can be determined. The status may relate to the quality of the seal.

A tube forming device 110 can be provided, configured to receive the web of packaging material 104 with the protective strip 106 applied. The tube forming device 110 can be further configured to form a tube 112 of the web 104 and attaching the ends of the web together. The tube forming device 110 can be further configured form a longitudinal tube sealing 402. The longitudinal tube sealing 402 is described in more detail in connection to Fig. 4.

A tube forming camera 114 can be provided, herein illustrated inside of the tube 112. The tube forming camera 114 can capture tube forming image data of the tube forming area 310. A polarized filter 116b may be provided in front of the tube forming camera 114 such that the tube forming image data is captured through the polarized filter 116b. The tube forming image data can depict the longitudinal tube sealing 402. The tube 112 can be sent to a filling and sealing device 1 18.

The roll fed packaging machine 100 described above is a simplification for illustration purpose. Such a machine may be achieved by installing a strip application camera 108 and/or tube forming camera 114 into an already existing roll fed packaging machine, such as the Tetra Pak Brick System.

Fig. 2 is a cross-sectional view of an overlapping area of the packaging material 202 that forms the longitudinal sealing. Put differently, it illustrates, in cross-section, by way of example, a part of a rear panel of the package where the two ends of the packaging material 202 meet in order to create the tube.

The packaging material 202 may comprise of an inner protective layer 206, an outer protective layer 204 and an intermediate strengthening layer 208. The intermediate layer 208 may comprise of one or more layers of material. As an example, the intermediate layer 208 may comprise a paper board layer. The inner protective layer 206 and the outer protective layer 204 may be plastic layers. A protective strip 106 may be provided on the inside of the package, with the purpose of creating a sealing between the overlapping ends of the packaging material 202. The sealing may protect the intermediate layer 208 from coming in contact with the food product held in the food package.

Fig. 3a illustrates, in top view, a section of the protective strip 106 and the web of packaging material 104. For reference purpose, the protective strip 106 may be divided into a first 306 and second 308 longitudinal side section. For reference purpose, the web of packaging material 104 may have a first 302 and a second 304 side section. Fig. 3b illustrates how the protective strip 106 is applied to the web of packaging material 104 by the strip applicator 122. The first side section 306 of the protective strip may be applied to the first side section 302 of the web of packaging material 104 such that the second side section 308 of the protective strip extends outside of the web of packaging material 104. The second side section 308 of the protective strip may later be applied to the second side section 304 of the web of packaging material 104. Also illustrated in Fig. 3b is a strip application area 310. The strip application area 310 may comprise an overlapping area 314, a heat affected protective strip area 312 and a heat affected web area 316. Even though illustrated to cover a part only, the strip application area 310 may in other embodiments extend along the longitudinal strip sealing 502. Fig. 4 illustrates the longitudinal sealing 402,502 in a tube 112 formed by the web of packaging material 104. A longitudinal strip sealing 502 of the protective strip 106 is illustrated along the first side section 302 of the web. A longitudinal tube sealing 402 of the protective strip 106 is illustrated along the second side section 304 of the web. A tube forming area 404 is illustrated as covering the longitudinal tube sealing 402 as well as a section of the web 104 outside the longitudinal tube sealing 402, and a section of the protective strip 106 outside the longitudinal tube sealing 402. Even though illustrated as a circular tube, the tube 112 may be of other shapes.

Fig. 5a illustrates, in top view, a strip applicator 122 configured to form a longitudinal strip sealing 502 between a protective strip 106 and a web of packaging material 104. The web of packaging material 104 and the protective strip 106 may be fed into the strip applicator 122. The strip applicator 122 may heat the protective strip 106 and the web 104. Further, the strip applicator 122 may press the heated protective strip 106 and the heated web of packaging material 104 together, thereby forming a seal between them, also referred to as a weld. In Fig. 5b, the strip applicator 122 is illustrated in side-view. The strip applicator 122 may comprise a heating element 504 for heating the protective strip 106 and the web of packaging material 104. The strip applicator 122 may further comprise means for applying pressure to the protective strip 106 and web of packaging material 104, herein illustrated as two rolls 506a, 506b being pressed together.

Fig. 6a to 6h are images of longitudinal strip sealings of different quality. Fig. 6a and 6b are examples of underheated longitudinal strip sealings. Fig. 6c to 6e are examples of normal longitudinal strip sealings. Fig. 6f to 6h are examples of overheated longitudinal strip sealings. Cracks 602 in the longitudinal strip sealings are visible, for instance in Fig. 6f.

Fig. 7 is a flow chart illustrating the steps of a method 700 for assessing quality of a longitudinal sealing 402, 502.

In a first step 710, strip application image data of the strip application area 310 may be received.

In a second step 712, features from the strip application image data may be extracted, wherein the features are related to effects of the heating provided by the strip applicator 122.

In a third step 714, a strip application status may be determined by evaluating the features, wherein the strip application status relates to the quality of the longitudinal strip sealing 502. In a fourth step 716, the strip application status may be transmitted, thereby providing a quality assessment of the longitudinal strip sealing 502.

Optionally, in a fifth step 702, the web of packaging material 104 may be received by the packaging material receiver.

Optionally, in a sixth step 704, the protective strip 106 may be received by the strip receiver.

Optionally, in a seventh step 706, the longitudinal strip sealing 502 may be formed by the strip applicator 122.

Optionally, in an eight step 708, the strip application image data may be captured from the strip application area 310 by the strip application camera 108.

Optionally, in a ninth step 726, tube forming image data of the tube forming area 404 may be received.

Optionally, in a tenth step 728, features from the tube forming image data may be extracted, wherein the features are related to effects of the heating provided by the tube forming device 110.

Optionally, in an eleventh step 730, the tube forming status of the longitudinal tube sealing 402 may be determined by evaluating the features, wherein the tube forming status is related to the quality of the longitudinal tube sealing 402.

Optionally, in a twelfth step 732, the tube forming status may be transmitted, thereby acquiring a quality assessment of the longitudinal tube sealing 402.

Optionally, in a thirteenth step 718, the tube 112 of the web of packaging material 104 may be formed by the tube forming device 110.

Optionally, in a fourteenth step 720, the first 302 and second 304 longitudinal side sections of the web may be attached by the tube forming device 110.

Optionally, in a fifteenth step 722, the longitudinal tube sealing 402 may be formed by the tube forming device 110.

Optionally, in a sixteenth step 724, the tube forming image data may be captured from the tube forming area 404 by the tube forming camera 114.

Even though described in a certain order, the different steps may also be performed in other orders.

Fig. 8 illustrates a schematic view of a server 800. The server 800 may be configured for assessing quality of a longitudinal sealing 402, 502. The server 800 may comprise a transceiver 802, a control unit 806 and a memory 804.

The transceiver 802 may be configured to enable the server 800 to communicate with other devices. The transceiver 802 may execute a strip application image data receiver 822 arranged to receive strip application image data of the strip application area 310. It may further comprise a strip application status transmitter 810 arranged to transmit the strip application status, thereby providing a quality assessment of the longitudinal strip sealing 502. The status may be transmitted to the roll fed packaging machine 100.

The memory 804 may be configured to store program code or modules. The memory 804 may comprise a strip application image data processing module 812 arranged to extract features from the strip application image data, wherein the features are related to effects of the heating provided by the strip applicator 122. It may further comprise a strip application status module 814 arranged to determine a strip application status by evaluating the features, wherein the strip application status relates to the quality of the longitudinal strip sealing 502.

The control unit 806 may be configured to perform the control of the functions and operations of the server 800. The control unit 806 may include a processor 808, such as a central processing unit (CPU). The processor 808 may be configured to execute program code or modules stored in the memory 804.

The transceiver 802 may be further configured to execute a tube forming image data receiver 824 arranged to receive tube forming image data of the tube forming area 404. It may further execute a tube forming status transmitter 816 arranged to transmit the tube forming status, thereby providing a quality assessment of the longitudinal tube sealing 402. The status may be transmitted to the roll fed packaging machine 100.

The memory 804 may further comprise a tube forming image data processing module 818 arranged to extract features from the tube forming image data, wherein the features are related to effects of the heating provided by the tube forming device 110. It may further comprise a tube forming status module 820 arranged to determine a tube forming status of the longitudinal tube sealing 402 by evaluating the features, wherein the tube forming status is related to the quality of the longitudinal tube sealing 402.

Fig. 9 illustrates a schematic view of a system 900 for assessing quality of a longitudinal sealing 402, 502. The system 900 may comprise of a server 800. The server 800 may be a server 800 as described in connection to Fig. 8. An artificial intelligence model 902 may be provided to the server 800 for determining a sealing status.

The system 900 may further comprise of one or more roll fed packaging machines 904a-c communicatively connected to the server 800. The server 800 may receive image data from the one or more roll fed packaging machines 100. As described in connection to Fig. 8, the server 800 may determine a status based on the image data and transmit the status to the roll fed packaging machine 904a-c corresponding to the image data. In addition, the server 800 may use the image data received by multiple roll fed packaging machines 904a-c to improve the artificial intelligence model 902. Put differently, the artificial intelligence model 902 may continuously learn from image data provided by the roll fed packaging machine(s) 904a-c. The server 800 may be a central server connected to a processing plant. In this case, the one or more roll fed packaging machines 904a-c may comprise the roll fed packaging machines of that processing plant. The server 800 may also be a central server connected to multiple processing plants. In this case, the one or more roll fed packaging machines 904a-c may comprise roll fed packaging machines of multiple processing plants.

The artificial intelligence model 902 may be a model designed to output a status of a longitudinal sealing 402, 502 based on extracted features from image data. The artificial intelligence model 902 may also take the image data as input and extract the features itself.

As a non-limiting example, the artificial intelligence model 902 may be an image classification neural network such as the ResNet 50 convolutional neural network. The artificial intelligence model 902 may be trained on images of longitudinal sealings labelled with statuses. For example, images such as those in Fig. 6a to Fig. 6h may be used to train the artificial intelligence model 902.

From the description above follows that, although various embodiments of the invention have been described and shown, the invention is not restricted thereto, but may also be embodied in other ways within the scope of the subject-matter defined in the following claims.