They offered three key formulas to help understand and increase packaging line productivity:
1. Machine efficiency is the ratio of the actual operating time divided by the total available production time. For example, if the actual operating time of a packaging machine was 301 minutes and the total available production time was 430 minutes, 301 divided by 430 would equal 0.7. Multiply by 100 to get a machine efficiency of 70%.
2. Line throughput is the total amount of products packaged in a shift divided by the amounts of minutes in a shift. So if a 240 bpm line ran for 301 minutes, it would produce 72곐 bottles. If the total shift was 430 minutes, line throughput would be 168 bpm.
3. Dynamic speed control is described as the equipment capability to change its operating speed given by the backup level experienced at the infeed end of the equipment.
Tips: The impact of dynamic speed control on line efficiency is that it enables a machine to lower its speed when an external stoppage occurs, running for a longer period of time before it stops. Dynamic speed control also increases line production throughput. When coupled with a buffer system (equipment that balances production output between work centers), dynamic speed control will be able to divide the line in two, creating a cushion between equipment. That helps the equipment run longer, with fewer stoppages.
Recommendations: The two speakers described a buffer case study in which the line’s initial conditions included a running speed of 240 bpm, with throughput at 168 bpm. Downtime was unknown. After observing the line, the study recommended adding buffer equipment that could accommodate 1ꯠ bottles before a labeler and operate at a speed of 210 bpm. The study projected an increase of line throughput to 200 bpm, with a 20% increase in efficiency. The implementation cost of $100ꯠ was projected to deliver a six-month payback.
For a more detailed look at this presentation, visit www.pmmi.org/ms/peconf/m14.pdf. —Jim Butschli
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