SPEED!

Part 1 of 2

In the first Mad Max movie there is a scene that takes place in a garage. In the background is a sign “Speed is only a question of money. How fast do you want to go?” The phrase sticks in my mind to this day.

Speed and money are also related in packaging machinery. In packaging, though, before answering the question of how fast we want to go we need to define “speed”.

I’ve spent the past 35 years working in hundreds, perhaps a thousand packaging plants. Invariably someone will refer to a machine or line as “high”, “medium”, or “low” speed. I have learned the hard way to use caution whenever anyone uses these terms. They are often more likely to confuse than to clarify, even among people in the same plant.

Production speeds vary dramatically by industry and product. An electronic product packaging line that runs 1-2 ppm (products per minute) might be considered high speed. A canning line running 1,000 ppm might be considered low speed.

My preference is to avoid use of the general terms high, medium or low speeds. Speed should be always be discussed in specific terms such as ppm. I am as guilty as anyone else of breaking this guideline but we should all try.

Another potential issue is defining the “product” in ppm. A canning line may run 600 ppm, and then pack those 24 per case. I have been in plants that would consider this a 600 ppm line. I have been in others which measure the case output and call it a 24 ppm line. Both are correct but unless one knows what is being measured both numbers are meaningless.

“Cycle speed” may also be used to discuss speed on some types of machines. Cycle speed on a thermoformer may be relatively fixed. However, the same machine might be able to run 2, 4 or 6 packages per cycle. A 50 cycle per minute speed 2 up will give 100ppm. Run that same cycle 6 up and speed will be 300 ppm.

Product sizes will add more confusion. Some machines will run at the same speed regardless of size. A capper, for example, probably doesn’t care how big the bottle is. The filler is another question and likely to run more slowly on a larger bottle. It may also run more slowly on a more viscous product. So in discussing the filler speed, does one use the speed of the fastest bottle/product combo? The slowest combo? The most frequently run? Something else?

A similar question applies to overall line speed. Overall line speed will be the speed of the slowest machine. But on which product/package combination.

The next issue is how to measure machine speed. The easiest way is to use a stopwatch, count a couple minutes worth of throughput, divide by the exact time of the counting and express the result in products per minute. Eg; in a period of 3 minutes, 12 seconds, 392 products pass. 392 products/192 seconds = 122 ppm.

Intermittent motion machines, such as inline filler, should usually be timed over a longer interval, 2-3 minutes, to assure accurate measurement.

The count must be over continuous operation in both cases. If there is a stoppage, restart the count when the machine restarts.

This is called the instantaneous speed. Some machines will have rate meters to indicate how fast they are running. (If they don’t, start installing them today. They are critical to smooth operation.)

I am not out of words but I am out of space. Think about the above and read Part II of this discussion next month.