Other Voices: Increasing production uptime and throughput in packaging applications

Editor’s Note: The following column by Chris Graff, vice president of sales and marketing at Butler Automatic, is part of Modern’s Other Voices column. The series features ideas, opinions and insights from end-users, analysts, systems integrators and OEMs. Click here to learn about submitting a column for consideration.

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Downtime, both planned and unplanned, can have pronounced impact on packing line efficiency and throughput. This downtime, caused by film roll changes, registration errors, catastrophic film failures, bottlenecks, and more, is costly, and may seem impossible to avoid. Taking appropriate steps to streamline processes wherever possible can help to mitigate the repercussions of downtime, improving your overall line efficiency and therefore profitability.

According to line efficiency studies, the single greatest cause of downtime in packaging lines is the time it takes to change over rolls of packaging film as they expire. Measured downtime runs close to an average of 3-5 minutes per roll change. If a company continuously running a single packaging line must change film rolls 10 times per day, the line loses an average of at least 30 minutes of production per day, or more than 8,000 minutes each year. Taking into account a similarly conservative estimate of 80 packages per minute and a $0.50 profit per item, the decreased throughput accounts for hundreds of thousands of dollars in potential profits lost per year.

Other causes of downtime in packaging lines also relate to film splicing. Improperly spliced film, for example, can lead to weak splices and splice failure during production. When the splice separates, or a weak spot in the film itself causes it to fail, the line must be shut down until the web path is rethreaded. This can take anywhere from 20 minutes to an hour in most applications, or two hours or more in aseptic applications where operators must re-sterilize machinery before restarting the line. Most packaging lines experience these kinds of critical failures about once every week.

Poor splices can also lead to registration errors in the film, where the film is improperly aligned and defective packages result. The registration error may result in barcoding issues, faulty seals, and/or package aesthetics that are simply unacceptable for consumer goods. These errors don’t cause downtime, but they can cause a great deal of waste and rework.

Bottlenecks are the final main cause of line downtime and inefficiency, and represent a significant loss of potential throughput. If one stage of a packaging line can handle 1,000 packages per minute, but the following stage can only handle 800, packages will accumulate between the two until the maximum accumulation is reached, at which point the first stage will have to be stopped or slowed until the excess packages are processed.

For packaging line operators and managers looking to increase line efficiency and throughput by minimizing downtime, the first step is to gather accurate information about the packaging line. Measuring and tracking performance can on its own help to improve performance, especially when people on the factory floor are engaged in the process. Employees who are encouraged to benchmark and objectively analyze their performance, as well as that of the line, become energized to find ways to create efficiencies. In this way, a culture of measuring and gauging emerges, to the benefit of the entire operation.

When line efficiency is maximized, each package is able to absorb more of the plant overhead. The existing capital structure can be utilized to fulfill more customer orders at what is ultimately a lower unit cost. Relatively small but highly strategic capital investments, such as automatic splicing machines or machinery to eliminate a single bottleneck point in the line, can be returned quickly and ultimately lead to even greater line profitability.