The faster I go, the behinder I get
Packaging lines bring out the speed drivers in all of us. Eons ago, back when I was a project engineer at Kraft Foods (as it was known then), our objective for every packaging line was to increase output. And the obvious way to do that was to run the line faster. Unfortunately, at some point, as you increase operating speed, production actually decreases, because you lose more product to problems than you gain from the increased speed.
I had a project to install 10-lane vertical form/fill/seal machines to produce small pouches of condiments. Complicating the operation, we ran up to eight different items. Each of these required dedicated machines settings, and there were no sophisticated HMIs with onboard memory. Each change required that all of the setting be changed manually. It took months to get the machines running at their rated speeds.
Inevitably, as sales increased, management decided that the least expensive way to meet requirements was to run the machines faster. After a lot of anguish and some machine modifications, we were able to increase production to some extent. And, when everything was perfect on all 10 lanes—packaging material, sealing temperatures, sealing times, web tension and alignment and much more—we could run the machines maybe 20 percent faster On some days, we could even maintain this speed for an entire eight-hour shift. Unfortunately, weekly output at this higher speed was almost always lower than the output at the slower sustainable speed.
A similar problem arises when you buy a new component for an existing line. It is only human nature to buy a faster machine than the one you had before. It’s the first step in upgrading the entire line. Unfortunately, the natural inclination is to run the line at the speed of the new machine. However, if the new filler you bought can run 300 bottles/min, but the labeler can only consistently run 280, you will encounter problems.
A number of years ago, I sat through a presentation that talked about packaging line optimization. The presenters defined this as maximizing the output of a packaging line given the constraints placed upon it, and presented a procedure to determine the optimum packaging line speed. Note that this was specifically aimed at a situation where you think you have increased the speed of your line beyond its capability, and does not apply to machine malfunctions or other mechanical problems.
This was before all of the sophisticated control and analysis systems that we have now, but I think it is still an interesting concept. For what it’s worth, here it is:
• Slow the line incrementally until your long-term (daily? weekly?) throughput peaks and begins to decrease.
• Continue to slow the line for a short period to make sure that you have really maximized throughput and that the throughput is stabilized across all shifts.
• Slowly increase speed until output starts to fall off. Then, go back to the sustainable speed.
Will Salley commented:
Balanced, that is what we aim for!
Dayanara commented:
Hey, that's a cevler way of thinking about it.
Dan F commented:
Jack I believe that was a presentation I made many years ago to a group of key Kraft engineers and managers and I also made a similar presentation at one of the Pack Expos. I believe the engineers on the line nodded their head in agreement with the process but the look on management's face was puzzling to say the least!! You know just turn the dial now to get the results now!!
Spud commented:
God, I feel like I sohuld be takin notes! Great work
Jim C. commented:
Interesting. Unfortunately, increasing the speed typically only requires setting a higher number at the control screen, or something similar. Then the offending culprit claims victory, walks away, and, later, beats everyone up for not achieving higher throughput. (Don't laugh, it happened at my last job.) Shortcuts seldom produce repeatable results.
If you study the line, test a higher speed, fix the issues that prevent it, test again, fix the issues, and so on, eventually you'll achieve higher THROUGHPUT. This is actually the desired result. But it takes more effort. (This was also accomplished at my last job, but after the offending culprit left the company.) In the end we increased throughput dramatically and still looked forward to additional future enhancements. And most "fixes" were very low cost.
Swanand Kullarwar commented:
what are the important sectors in which a packaging engineer can work apart from design and production?
Leon commented:
Stabalizing throughput on a line is certainly attainable. Statistics, documentation and excellent communication being important factors.
Team member/Operator buy-in to all of these changes is just as big of challenge! Yes/No?
Kayla Holman commented:
Hi Jack,
Working for a packaging distributor, I'm not exposed to the intricacies of manufacturing and filling processes very often. Thanks for expanding my point of view through sharing your story and insights.
