Top Quality Closures:
Insight Control Offers a Vision for Reducing Defects

Bill Flowers, Insight Control Systems Inc.

Lids. Caps. Tops. Whatever you call them, they're everywhere - a part of daily life that you take for granted, and barely notice. Until a jar of pickles explodes all over your grocery cart, or you open a new bottle of medicine, only to find the safety seal broken.

It's not hard to see why these so-called 'closures' are one of the fastest growing markets in the packaging industry. Making them fault-proof is the goal of Insight Control Systems, which has been designing closure-inspection systems since 1993. Our QNX 4-based Insight 100 combines high-speed mechanical handling technology and patented illumination systems to single out defective closures for everything from motor oil to peanut butter.

The Insight 100 singles out defective closures for everything from motor oil to peanut butter.

Quality not quantity While it doesn't necessarily make inspections any faster, the Insight 100 improves a plant's bottom line by increasing the efficiency of the production cycle. To be cost-effective, inspection systems need to look at some 2,000 closures every minute. At that rate, it's virtually impossible for the human eye to thoroughly check anything. Mistakes easily slip through and end up being shipped to the customer, who may choose to send the load back if there are too many bad closures. This 'scrap rate' translates into lost revenue and credibility for the manufacturer. And, though faulty closures rarely make it into the hands of consumers, if they do, the result may be as minor as a scratched lid or as serious as a defective childproof band that could pose serious health risks.

With the Insight 100, final throughput remains relatively unchanged, but the scrap rate is significantly reduced. The manufacturer chooses the number of variables the system needs to check - such as color uniformity, stripped threads, and contaminated seals - in a given time span. At 2,400 closures a minute, the system can check for eight or nine variables. At slower speeds, it can handle as many as 20 inspections.

On the line

In a typical production scenario, closures are inspected single file, on either a conveyer or starwheel line. One computer tracks each part throughout its time on the inspection line. It first tracks the closure for several inches until it reaches the camera, then messages the second computer that the closure is ready to be photographed. Another computer fires the camera and sends a digital picture to the third computer, which analyzes the resulting data. Using the camera to inspect light variances reflected from each closure, the Insight 100 compares changes in light variance from pixel to pixel. The system digitally converts light into gray-scale patterns and can determine contrast down to 1/256 of a light-level change.

Lids. Caps. Tops. Whatever you call them, they're everywhere - a part of daily life that you take for granted, and barely notice. Until a jar of pickles explodes all over your grocery cart, or you open a new bottle of medicine, only to find the safety seal broken.

It's not hard to see why these so-called 'closures' are one of the fastest growing markets in the packaging industry. Making them fault-proof is the goal of Insight Control Systems, which has been designing closure-inspection systems since 1993. Our QNX 4-based Insight 100 combines high-speed mechanical handling technology and patented illumination systems to single out defective closures for everything from motor oil to peanut butter.

Closure manufacturers choose the number of variables the system needs to check - color uniformity, stripped threads, contaminated seals, and so on - in a given time span.

The Insight 100 singles out defective closures for everything from motor oil to peanut butter.

Quality not quantity

While it doesn't necessarily make inspections any faster, the Insight 100 improves a plant's bottom line by increasing the efficiency of the production cycle. To be cost-effective, inspection systems need to look at some 2,000 closures every minute. At that rate, it's virtually impossible for the human eye to thoroughly check anything. Mistakes easily slip through and end up being shipped to the customer, who may choose to send the load back if there are too many bad closures. This 'scrap rate' translates into lost revenue and credibility for the manufacturer. And, though faulty closures rarely make it into the hands of consumers, if they do, the result may be as minor as a scratched lid or as serious as a defective childproof band that could pose serious health risks.

With the Insight 100, final throughput remains relatively unchanged, but the scrap rate is significantly reduced. The manufacturer chooses the number of variables the system needs to check - such as color uniformity, stripped threads, and contaminated seals - in a given time span. At 2,400 closures a minute, the system can check for eight or nine variables. At slower speeds, it can handle as many as 20 inspections.

The Insight 100 must inspect over 2000 closures per minute - something that's virtually impossible for human inspectors to do thoroughly.

On the line

In a typical production scenario, closures are inspected single file, on either a conveyer or starwheel line. One computer tracks each part throughout its time on the inspection line. It first tracks the closure for several inches until it reaches the camera, then messages the second computer that the closure is ready to be photographed. Another computer fires the camera and sends a digital picture to the third computer, which analyzes the resulting data. Using the camera to inspect light variances reflected from each closure, the Insight 100 compares changes in light variance from pixel to pixel. The system digitally converts light into gray-scale patterns and can determine contrast down to 1/256 of a light-level change.

By the time the closure reaches the end of the line, the first computer informs the third computer whether the part passes or fails the inspection, and tracks the 'fail' to a rejecter, which throws it off the line. If the Insight 100 doesn't have enough time to adequately check a closure, it's automatically rejected.

The Insight 100 is also able to monitor the individual performance of each tool in the assembly line. Caps, for instance, are made in an injection molding device and sent to a machine that squirts the liner into it as a hot drop of plastic, then stamps it into the desired shape. The Insight 100 inspects both the liner and the cap, tracking which tool - out of a possible 32 - formed which liner. If a tool is making a significant number of rejects, a customer can choose to shut down the lining machine and fix the tool, or continue using the machine and throw away all the caps from the defective tool.

Using the complete OS in each Insight 100 makes our system fast and robust, and easily changeable and configurable.

Making the connection

Since each inspection cycle must take no more than 25 milliseconds, it's an environment that demands hard realtime performance. Connectivity is also key in facilitating communication between the back office and the factory floor. QNX provides both and the ability to use the system as a powerful device for process control.

One of the things that makes the Insight 100 competitive is that it's actually made up of two dozen cooperating tasks communicating with message passing. We take full advantage of everything QNX has to offer and use the complete OS in every Insight 100. This not only makes our system fast and robust, it makes it easily changeable and configurable.

In the five years the Insight 100 has been available, over 100 have been installed in more than 15 countries around the world, and a new version is about to be released. Beyond that, we're looking at the Photon microGUI for our next-generation product, expected out later this year. Planned enhancements will focus on speed and the use of micronetworks of cells working together to perform even more thorough inspections.

Crowning glory

As for the closure market, we are hoping to expand our boundaries by targeting anything that can be considered a closure - beer bottle crowns, plastic caps, metal caps, can ends, and even cans and bottles themselves.