QIPCam demo report. January 11 th 2013, Cédric Bravo. Table of Contents. 1 Goal of the demonstration

Size: px

Start display at page:

Download "QIPCam demo report. January 11 th 2013, Cédric Bravo. Table of Contents. 1 Goal of the demonstration"

Gloria Chambers
6 years ago
Views:

1 QIPCam demo report January 11 th 2013, Cédric Bravo Table of Contents 1 Goal of the demonstration Overview of the experiment Thermoform disturbances monitored by QIPCam Holes in the tray Bottom plate inhomogeneity Detection of induced errors in the thermoforms Thermoform heating homogeneity Seal inspection Conclusions thermoform inspection seal inspection Goal of the demonstration The goal of this demonstration was to confirm the observation made during a previous study on the same machine in July This study consisted of preforming quality assessments on thermoformed packs and on the seal of thermoformed packs.

2 Overview of the thermoform experiment During the demo the camera was pointed on a recently

Temperature images were stored for every package produced during the test.

acquired. The time span between sealing and image acquisition must be constant.

2 2 Overview of the thermoform experiment During the demo the camera was pointed on a recently shaped thermoformed empty package (Figure 1). Temperature images were stored for every package produced during the test. Within a limited time span after sealing, an infrared image of the recently produced seal is acquired. The time span between sealing and image acquisition must be constant. As such thermoform images are comparable, and disturbances in the pack can be observed with highest precision. Two mirrors were placed in order to have a good viewing of the vertical tray walls. Figure 2 illustrates the camera field of view. Figure 1: sketch of the QIPCam set-up during the test. Figure 2: example of a QIPCam image of a thermoformed tray during the July measurements.

The thermoform structure clearly comprises several regions: a thick hot bottom plane, four cooler thinner vertical walls and the thick hot top foil.

3 Thermoform disturbances monitored by QIPCam Disturbances of thermoform were observed. Examples are shown below.

3 The thermoform structure clearly comprises several regions: a thick hot bottom plane, four cooler thinner vertical walls and the thick hot top foil. The temperature in the corners is much lower than in the rest of the tray, suggesting that the thickness in these corners is much smaller. 3 Thermoform disturbances monitored by QIPCam Disturbances of thermoform were observed. Examples are shown below. In large production runs, these disturbances can accurately be observed by QIPacks software. 3.1 Holes in the tray Holes in the tray cause large temperature differences. Even the slightest hole creates significantly different QIPCam image patterns. Figure 3 illustrates a hole in a tray after thermoforming. Figure 3: example of a hole in the tray during the July measurements Figure 4: example of a hole in the tray during the November demonstration

3.2 Bottom plate inhomogeneity Large temperature differences can also be found on the bottom plate (Figure 5) Figure 5: left: example of a tray

supermarket In Figure 5 three large deviations can be observed: a diagonally shaped thick material front (hot diagonal), a large cold spot in

A similar thermoform error was found on a tray from a Belgian supermarket (Figure 5).

4 3.2 Bottom plate inhomogeneity Large temperature differences can also be found on the bottom plate (Figure 5) Figure 5: left: example of a tray with very large thickness differences due to unequal material distribution; right: same error type example found on a tray in a Belgian supermarket In Figure 5 three large deviations can be observed: a diagonally shaped thick material front (hot diagonal), a large cold spot in the top left corner of the bottom plate and a colder horizontal line on the right. A similar thermoform error was found on a tray from a Belgian supermarket (Figure 5). In analogy to these observations, unequal temperature and thus material distribution was found during the November demonstration (Figure 6). Figure 6: example of trays with very large thickness differences due to unequal material distribution during the November demonstration

3.3 Detection of induced errors in the thermoforms Finally to have an idea about the precision at which an error could be detected, the small holes were cut in the foil, before thermoforming.

5 3.3 Detection of induced errors in the thermoforms Finally to have an idea about the precision at which an error could be detected, the small holes were cut in the foil, before thermoforming. The results are illustrated in Figure 7. A pinhole clearly induces a large decrease in temperature. Figure 7: illustration of 2 cuts and a pinhole in the thermoformed pack. 4 Thermoform heating homogeneity After the July measurements, questions were raised about the homogeneity of the heating of the foil. Qipack has performed a measurement in which the foil was heated, but not thermoformed. This way, the heating homogeneity can be investigated (Figure 8).

Figure 8: image of the foil before thermoforming, but after heating.

Figure 8 clearly points out that the heat is homogenously applied on the foil: the heating variation is app 3 C.

On both July 19 th and November 15 th 2012 the camera was pointed on a recently sealed package (Figure 9).

6 Figure 8: image of the foil before thermoforming, but after heating. The same image is illustrated left in a large temperature scale, right in a small temperature scale. Figure 8 clearly points out that the heat is homogenously applied on the foil: the heating variation is app 3 C. 5 Seal inspection In analogy to the tray analysis, heat seals on the trays were investigated. On both July 19 th and November 15 th 2012 the camera was pointed on a recently sealed package (Figure 9). Temperature images were stored for every seal produced during the test. Within a limited time span after sealing, an infrared image of the recently produced seal is acquired. The time span between sealing and image acquisition must be constant. As such seal images are comparable, and disturbances in the seal can be observed with highest precision. Figure 9: camera set-up for the seal investigation Figure 10 illustrates a typical heat seal QIPCam image. The seal is clearly detectable around a hot foil.

Figure 10: typical QIPCam image after sealing.

(right) When powder is trapped in the seal, high temperatures are

Figure 11 illustrates a large sealing problem during the July study.

7 Figure 10: typical QIPCam image after sealing. during the July study (left) and during the November demonstration (right) When powder is trapped in the seal, high temperatures are observed. Figure 11 illustrates a large sealing problem during the July study. Figure 11: example of large powder presence in the seal during the July study Figure 12,left, illustrates small powder presence. Clearly this causes a hot spot in the seal.

Figure 12: illustration when a little powder is trapped in the seal (left) and compared with a good seal (right) during

seal (right) during the November demo. Remark the detection of the lasered pre-cut.

temperature. This is in agreement with the measurements performed on a VFFS machine on November 29-30 th, 2012.

these temperature variations are related to trays thickness variations 3.

8 Figure 12: illustration when a little powder is trapped in the seal (left) and compared with a good seal (right) during the July study Figure 13: : illustration when a little powder is trapped in the seal (left) and compared with a good seal (right) during the November demo. Remark the detection of the lasered pre-cut. Both measurement campaigns pointed out that milk powder trapped in the seal is detectable by a local increase in temperature. This is in agreement with the measurements performed on a VFFS machine on November th, Conclusions 6.1 thermoform inspection 1. thermoformed trays show high variation in temperature 2. these temperature variations are related to trays thickness variations 3. thickness in the bottom corners is critical, and probably much to small 4. typical problems such as unequal material distribution and holes are very well mapped by the QIPCam 5. active cooling of the thermoformed trays should be considered

9 6. the foil on November 15 th was homogeneously heated 6.2 seal inspection 1. seal thickness and temperature variations are well mapped by the QIPCam 2. trapped powder in the seal causes higher temperatures which are easily detectable by QIPCam

Aspect Ratio Considerations for Flat Bottom Hole Defects in Active Thermography

More info about this article: http://www.ndt.net/?id=20749 Aspect Ratio Considerations for Flat Bottom Hole Defects in Active Thermography Abstract by M. Frendberg Beemer and S. Shepard Thermal Wave Imaging,