Use Buffer Systems to Optimize Packaging Efficiency
Accumulating buffer systems ensure greater uptime along production lines, reduce product backups and enhance throughput.
By Manuel Rey, Schering-Plough, and Ignacio Muñoz-Guerra, AutoPak
The four figures that accompany this story are contained in a 4-page PDF document that may be accessed by clicking the "Download Now" button at the end of the article.
Maintaining packaging efficiency is essential to meeting the cost and productivity challenges inherent in today’s pharmaceutical manufacturing. Packaging lines must run at optimum levels and experience as little downtime, planned or otherwise, as possible. Accumulating buffer systems offer manufacturers one clear solution to address these issues.
Accumulating buffer systems are temporary storage spaces that allow product flow to continue whenever backups or downtime occur. With any such system, if the disruption on the line is cleared within a short time frame (typically within a few minutes), product is automatically metered back into the production flow.
The systems can be installed in various locations along the line, depending on which process steps tend to experience the most stoppages. A common location is before the labeler, which historically experiences more downtime than other line equipment. Most packaging lines installed in pharmaceutical plants today feature at least one buffer.
The cost of installing and implementing a buffer system is not minor, but the return on investment in most cases is quickly realized. Since buffer systems isolate individual consecutive processes, they enhance the ability of each machine to achieve maximum performance and facilitate continuous production flow. While they usually do not contribute to the packaging process like filling or capping machines, buffer systems add value to the line by helping to balance production and increase throughput. A common misconception is that buffer systems hide inefficiencies in the line, whereas in reality they enhance efficiencies.
This article discusses the myriad choices available in buffer systems and provides suggestions for firms to conduct their own buffer studies to see if such systems are practical or beneficial. In addition, we provide a case study of a successful buffer analysis at one pharmaceutical plant.An assortment to choose from
There are several types of accumulating buffer systems available, each with different geometries, requirements, capabilities, advantages and disadvantages. They are dependent upon product size, shape and orientation on the line, line speed, and accumulation requirements. Major accumulation categories include:
- in-line continuous accumulators (serpentines, alpines and extending belt systems)
- batch indexing accumulators (vertical and horizontal)
- random continuous accumulators (bi-directional, counterflow and turntables).
In addition, buffer systems can be categorized in terms of product flow:
Conducting a buffer study
- First-In First-Out (FIFO) systems ensure that the first product entering the queue is the first product to leave. Often in alpine form, FIFO systems have a small footprint and utilize a small amount of floor space when compared to other buffer configurations. Ideal for pharmaceutical manufacturers, FIFO buffer systems allow for product accountability (i.e. lot number, production time) for tracking at a later date.
- In First-In Last-Out (FILO) systems, products leave their queue in the reverse order from that in which they arrived. FILO buffer systems are available in horizontal or vertical formats.
- The most common systems operate on a First-In Random-Out (FIRO) basis. Often in turntable format, FIRO buffers are either bi-directional, or counter-flow operations. Of course, FIRO systems offer no product accountability or sequencing.
A thorough buffer study is essential in determining whether a system will lead to increased efficiency and output, whether its cost is economically justifiable, and in assessing the system’s optimal capacity, location and speed. While the study may be done in-house, many firms choose to enlist the help of third-party consultants with experience in preparing buffer studies and implementing buffer systems.
The first step in a buffer study is to identify downtime, planned and unplanned. Firms must look at scheduled downtime, to change a label roll or case-sealer tape roll, for instance, and identify the activity, duration and periodicity for each piece of equipment in the production line.
Unscheduled downtime resulting from machine jams or breakdowns is more unpredictable and thus difficult to evaluate. Buffer analysts should observe the line over several shifts and collect historical data as to the nature and frequency of stoppages. “Guaranteed minimum” efficiency information can also be used as a guideline for downtime duration and frequency. For new equipment purchased, OEMs can provide the theoretical or historical downtime of the equipment as a reference point.
Data taken from the field is then input into a prepared algorithm in order to produce accumulation simulation charts for all equipment. While the analyst will already have a good sense of how and where the line might benefit from an accumulation buffer, the charts can be used to verify these hunches. The case study below provides a more detailed look at the process of preparing and analyzing accumulation simulation charts and performing a buffer study in general.
The completed buffer study will allow the packager to decide whether the investment in a buffer system can be justified. In general, systems become justifiable when a line tends to experience minor downtimes (stoppages of 10 minutes or less) and the buffer is able to accommodate it. When a line typically faces major downtimes of 10 minutes or longer, buffer systems do not provide the necessary support to warrant the investment. Major downtime, of course, suggests that a packaging line has other issues in need of evaluation and improvement.