Dairy Crest, a leading UK chilled dairy foods company, has upgraded its vision system for automated inspection of milk bottles in an effort to improve the quality of the product released. The system was required to cope with a production volume of 400 million litres of milk a year, processed at the company's facility in Chadwell, Essex, UK.
PCS Industries designed and built a modular system to perform a number of inspection tasks on standard plastic milk bottles ranging from two to six pints and a two-litre version. The system consisted of a DVT 545 colour camera, Mitsubishi PLC, touch-panel PC and a high speed reject unit. A custom graphical user interface (GUI) runs on the touch-panel PC and handles the communication between the various modules. Dairy Crest operatives therefore can access all relevant settings and parameters through the GUI. The system also offers further capabilities as it has inputs for additional sensors for label detection, cap foil presence and faults from the filler.
The modular system is installed on three separate yet identical production lines and checks the presence, colour, height and angle of each bottle cap, running continuously at a speed of 220 bottles per minute.
After filling, the bottles are automatically channelled along a conveyor and taken to the inspection area. The DVT cameras are housed in wash-down enclosures and fixed to the side of each line where they capture the required images as each bottle passes along the line. The advanced vision capabilities of the DVT camera ensures all required inspection checks are performed from just one image. At the same time, the system also tracks filler faults (e.g. under fill), missing labels and missing foil. All passes continue to an automated packing area where they are loaded onto trolleys for distribution to the customer.
Those bottles that do not conform are removed from the conveyor by an advanced high speed reject system which directs the bottles onto a separate reject conveyor. The PCS solution accomplishes this even when the bottles are close together. Statistics are kept which show counts for all the different reject reasons. This allows easy access to important information to ensure productivity is maintained at maximum output levels.
Steve Cottam, packaging area engineering manager at Dairy Crest, commented: 'The system has proven to be robust and reliable and is incredibly easy to use. We have seen a significant decrease in customer complaints from leaking bottles and the systems have required little or no adjustment or maintenance. PCS listened to our objectives and have fulfilled and exceeded all expectations by delivering a cost-effective solution which has improved our productivity.'
