Control system for the presence of foreign objects inside of plastic containers

The food industry has high demands for the quality and safety of the products. These demands are placed not only on the foodstuffs but also on the packaging in which the final products are supplied to the market.

Visual control based on the machine vision enables the packaging manufacturers to reject the defected units directly at their production stage. As a result, the overall quantity and associated costs of the defected products decrease substantially, whereas, the quality of the final product improves.

Automated control system for detection of foreign objects inclusion inside of plastic containers based on the machine vision smart camera and specialised background illumination performs the following:

• 100% control of the containers at the production line
• Control of the moving containers at a speed of 4 containers per second
• Automatic rejection of defected units
• Display of the results on the operator panel in a form of graphic information

The system controls the following defect types of the plastic containers:

1. Any evident deviations in luminance (e.g. roll of plastic, presence of holes)
2. Presence of plastic foreign objects at the bottom of container of a diameter 3 mm and up

Principle of system operation:

1. Sensor that monitors the object presence sends the signal to the camera when the container enters the control zone.
2. The system takes the image based on the prespecified parameters for exposure.
3. The system performs the analysis for the bottom of a container. At this stage the system searches for objects that are in the product rejection range specified by the control algorithm.
4. In the case of defect detection, the signal is sent to reject the defected container, which is then removed from the production line. In the case of defect absence – such signal is not issued.
5. The results of system analysis are displayed on the operator panel in a form of graphic information.

This system has been implemented at ALPLA in city of Chekhov.