A Closer Look at Inspection Tools

Quality monitoring begins at the production line but doesn’t end there. Flagging issues with packages and even utilities in real time also is important.

By Kevin T. Higgins, Managing Editor

Manufacturing need and scientific development have a horse-and-carriage relationship: without the former, the latter isn’t going anywhere. In-line and at-line instrumentation illustrates the point.

Mass spectrometry has gone from exotic to affordable in the past decade, but interpreting what absorbed light is saying about material composition requires R&D that isn’t funded unless there is market demand. “Change is driven with the marketplace in mind,” reflects Ray Shead, marketing manager in the Irwindale, Calif., offices of NDC Technologies.

If a food company’s customers — be they retailers, foodservice operators or other food manufacturers — are willing to pay a premium for greater consistency and less variability, the manufacturer will invest in the tools that help deliver it. That demand, in turn, will drive suppliers to develop superior instruments to support process control.

A case in point is NDC’s MM71e near-infrared (NIR) gauge. The fact that the gauge can provide real-time feedback on six product variables is nothing new; the firm has made instruments that can measure moisture, collagen, protein, degree of brownness, fat and other variables for 10 years. But acrylamide formation in fried foods such as potato chips is a major concern in Europe, and the improved precision of the new gauge is a direct outgrowth of the demand for instruments that can monitor variables that result in acrylamide.

Product consistency is not manufacturers’ only concern. Five plant utilities — water, (compressed) air, gas, electric and steam, known by the acronym WAGES — traditionally were viewed as fixed costs, but there is increasing recognition that they are variable costs that directly impact the bottom line. Interest ebbs and flows in parallel with energy costs, but driving down WAGES is becoming a manufacturing priority, and suppliers are responding.

Operating a steam system is a significant cost, and manufacturers can draw from an array of controls instrumentation to operate those systems. Monitoring quality dimensions is more problematic, which is why Ola Wesstrom, senior industry manager-food and beverage at Greenwood, Ind.-based Endress+Hauser USA, calls the firm’s new vortex meter “truly a game changer for steam monitoring.”

Measuring the amount of steam generated by boilers and distributed through the plant can be accomplished with simple devices, but the quality of the steam requires the sophistication of the vortex meter, Wesstrom explains. “The energy in wet steam is significantly less than the energy in dry steam,” he says. The on-board microcomputer in the vortex meter is able to calculate steam moisture levels and help technicians pinpoint problem areas.

Multi-task inspection

Process control isn’t useful once the process is complete. As a result, in-line inspection of packaged goods draws on some of the most advanced technologies used in food and beverage, particularly in high-speed bottling operations.

Gamma and X-ray inspection units have been used for decades in bottling halls. While those machines will continue to be used to check fill levels, the use of radioactive elements, even in small quantities, gives processors headaches when machines reach the end of their useful lives. Of even greater concern is their inability to perform the types of quality monitoring that newer packaging materials present. PET bottles are an example, with the lightweighting of containers magnifying the consequences of bottle variances that weren’t a big deal in years past.

A superior solution is the smart camera, according to Vince Barbarie, senior product engineer at Filtec Ltd., Torrance, Calif. Instead of relaying image data to a complex and slow central processor, the smart camera has built-in processing capabilities that allow it to make the good/bad call by itself. Filtec’s first commercial application is PETtec, a full-container vision system that grew out of a project with Coca-Cola.

PETtec’s three black-and-white cameras, plus an optional color camera, perform multiple inspections at speeds of 1,400 bottles per minute, or 1,000 per minute “with all the bells and whistles turned on,” says Barbarie. Missing codes, over-torqued caps, excess fill levels, damaged tamper bands and other defects are detected, but perhaps the biggest benefit is the feedback it provides on upstream performance.

The system’s computational power goes beyond monitoring the performance of individual fillers. “At one of the first installations, thanks to the heuristics in the machine, they were able to trace the source of filling issues to the way the bowl filled between batches,” Barbarie reports.

Faster processing speed, higher-resolution images and other technical advances make machines like PETtec possible, but software development that takes the raw data and “turn it into meaningful information for the customer” wouldn’t occur if there wasn’t a market for it, he reflects.

The shift from glass to PET bottles is creating a need for more comprehensive inspection, and the emergence of premium beverages increases the importance of fill-level precision. “The makers of high-end juices don’t want to overfill even a fraction of an ounce,” Barbarie points out. For narrow-neck bottles, the new machine can reduce product giveaway to less than 2ml. That was enough to give one bottler an ROI in six months.

In-line measurement draws from many technology sources, but developing the core technology behind it requires an application that manufacturers are willing to pay for. When the need and the capabilities mesh, inspection tools that help food companies enhance quality and reduce costs are born.

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