By Andrew Eddleman, Applications Engineer


The challenge of properly inspecting container closures is a task as old as civilization, the importance of which affects industries from Pharmaceutical to Consumer Goods to the Food & Beverage Industry. Within the genre of bottle container closures, there are Swing Caps, Crown Cork Caps , Flip Top Caps, Twist Caps and Cap and Crimp to name a few.  As the types and styles change, so do the necessities for product inspection. Machine vision, as opposed to other product inspection methods, is adaptable enough to fit the needs of today’s manufacturing demands. Here are 3 reasons why you should utilize machine vision for cap inspection:

1)   Vision Systems Are More Adaptable at Higher Speeds
At rates exceeding 1000 parts per minute, there is no feasible way that an operator can guarantee a product is in spec. Previously, sensors were used in industry as a stop gap to guarantee that the cap was correctly seated on the product; however, as cap design has changed there now can be several different skews of a cap running down a single line. A vision system can now be adaptable enough to go from inspecting a swing cap on a glass lemonade bottle to a twist type on a plastic container. Because of high variability in the style and color, manufacturers are forced to inspect multiple features in different types of lighting. The color of each cap can uniquely identify the product (such as in Dairy) and may also have an identification code for the product. Performing these inspections on a dynamic product line at a fast rate is no longer in the realm of human operators and is quickly outpacing what a simple sensor can perform.

2)   Tray Inspection Systems accurately count reflective products
While Information technology is exploding in growth for production lines throughout the world, counting products accurately has become much more important. This information can be fed back to a central database to monitor plant efficiency and find or prevent problems. Traditionally, counting has been done with simple sensors (such as photoeyes) fed back into a machine controller (such as a PLC). This was done to keep complexity and cost down, and for a time it was very successful. Now, as product lines have to hold more and varied products, the types of sensors capable of counting these caps have disappeared. New machine vision technology, such as embedded cameras and inline vision systems, has stepped up to count caps as they come down a conveyor, while other more complex vision systems may be needed to handle highly reflective caps in a batch or tray. In the Pharma industry, highly reflecting vial caps and closures on ampules can be very difficult for a machine vision application to effectively count in one snapshot. Therefore, Acquire Automation has created a Tray Inspection System that utilizes machine learning algorithms to negate stray reflections off of individual units that may alter a unit count.

3)   Area scan can help determine the position and angle of a cap which can predict leaks and seal issues
The position and orientation of a cap with respects to the neck and opening of a bottle or container can tell a lot about whether the product is effectively sealed.  A seal provides both a means to prevent leaks (liquids getting out) as well as a barrier to spoilage (air and bacteria getting in). Vision Inspection Systems can monitor these factors either through measurements to a feature on the product or by matching to a master template. For Screw type caps, the measurement would begin with identifying the top of the cap with respects to a ridge on the neck of the bottle. With flip top caps, the inspection may identify if the cap is flipped up and at an angle. These proportions can then be compared to parameters that can estimate whether contamination or a leak can occur. Another use for a cap is to hold a foil seal as well as an insulation barrier. In these instances, a cap holds the foil to the top surface of the container during the induction sealing process. If the cap is out of position then the foil seal may be incorrectly seated and will not accurately adhere to the product. In this case, a vision system can be used to determine how far out of position the cap is and check whether the induction seal process was successful.

Acquire Automation makes cost effective vision systems to perform cap inspections that will guarantee zero downtime along with zero false failures. These machines can keep up with ever changing quality requirements and manufacturer designs. To learn more, contact us today.