There are thousands of things to see during a plant tour. However, if you really want to know how good the plant is, there are a couple of tricks on what to watch during the tour. This post will give you a few quick but reliable metrics to estimate the performance of the plant.
Update: Due to popular demand i have added a Lean Shop Floor Visit Checklist.
Surely you’ve visited a manufacturing plant before. As for me, even though I’ve been in hundreds of plants, I always find the experience overwhelming. There is a mass of machines, workers, parts, and tools. Additionally, a guide tries to give you an overview of the plant, usually ripe with technical terms, abbreviations, and local plant lingo that you can barely hear over the noise of the work. In short, the deluge of information easily overwhelms you, and after the tour you only remember that the machines were green (in older plants) or grey (in more modern plants). As for what you could have learned about the plant, it may have been a waste of time.
This offers suggestions to help you get the most out of your plant tour. The key of the tour is FOCUS! Don’t try to take in everything. Rather, focus on different areas of interest. Decide what you’re most interested in before you visit, and then focus on that topic. Another of my posts talks about how visitors are manipulated during a plant tour in order to keep them in the dark.
One area many visitors are interested in is efficiency—how well does the plant run? This is very important if you’re a high-ranking manager visiting one of your plants, if you want to evaluate a purchase of the plant, or if you’re interested in a joint venture. In these cases you want to know how well the plant is run.
One element to focus on are the workers. How many of them are working productively, and how many are not? This is actually rather easy to do. Just check how many workers you can see, and how many of them are working productively in the moment you look at them. And, by working productively, I mean actually working on a product and creating added value for the customer. Here are a few things that don’t count:
- Walking around
Only true “hand-on-the-metal” work counts as productive. The number of productive workers compared to all workers is a very good measure to quickly get the gist of a plant’s productivity. And these numbers may surprise you. Among the best I have seen is within Toyota plants, where between seven to nine out of ten workers are actually working. This is best of bench(mark).
In an average Western plant, these numbers don’t come anywhere close to Toyota’s performance . In my experience, only around five out of ten workers are actually productive, while the rest may still be busy but not productive. I’ve even seen plants where only three out of ten workers added value to the customer. Imagine the waste if more than half of your workers do not create value for the customer!
In any case, the percentage of workers adding value is a quick and dirty but reliable check of a plant’s productivity. It certainly beats any official numbers you get from plant management staff who mainly want to look good. Hence, official numbers are usually highly unreliable if not outright fudged.
You can repeat the same exercise for machines. How many machines are actually working when you look at them? An average Western plant may have around three to five out of ten machines actually working. Again, being under repair or set up for the next job does not count as work.
While at first glance these numbers are even lower than for worker productivity, this is actually the way it’s supposed to be. Machines are usually highly specialized, whereas human workers are much more flexible. Or, as NASA put it:Man is the lowest-cost, 150-pound, nonlinear, all-purpose  system which can be mass-produced by unskilled labor.
Hence, it is better if your machines wait and your workers are busy than the other way around. Overall, counting workers tells you more about the plant than counting machines, but counting machines may be useful for highly automated lines (for example, robotic car body welding lines).
Yet another area of interest for many visitors is inventory. In a Western view, lean manufacturing is often associated with low inventories. While this is an oversimplification, high inventory is an indication of a poorly run plant. It’s a bit more difficult to understand the inventory situation from a plant tour, but it is possible. First of all, check for some obvious signs of dead inventory:
- Look for dates on material sheets or inventory stickers. While the vast majority is naturally pretty recent, try to find the oldest ones. I frequently find lots of boxes in excess of five years of age.
- Look for dust. The thicker the layer of dust, the older the part. Naturally, you have to adjust this for the environment (for example, two days in a foundry will create a thicker layer of dust than twenty years in a semiconductor fabrication).
- Are there any blocked stocks or stocks that are not to be used for quality or other reasons? A key telltale sign is red stickers warning against the use of the material, often giving the reason. Very interesting information!
Of course, the question of what’s good and what isn’t depends on the details of the business. A plant for spare parts or low-volume, high-variety production may necessarily have much older stock than a high-volume mass-production plant. The value of the product is also of interest. Where lack of hard data exists, size or weight give a rough estimate of value. Hence, a two-year-old pallet with tons of material may be worse than a two-year-old box of screws.
It’s sometimes also possible to estimate the reach of inventory. Look at how often the inventory is moved (for example, how often someone takes out a box or a pallet). Relate this to the total inventory on hand. So, if three pallets were taken out in ten minutes’ time, but the storage holds around one thousand pallets, then there are enough parts for 333 times ten minutes or around seven shifts’ worth of work.
Again, doing this exercise at the incoming goods area at a Toyota plant gives around two hours’ worth of material, whereas in the Western world it may be closer to two weeks’ worth of material. Again, different businesses need different inventory levels.
However, be aware that your observations apply only to the material you see. It doesn’t apply to the material on the road or the material stored elsewhere. Many Western plants pride themselves on their low-inventory reach but conveniently forget to mention the outsourced but still-paid-for warehouse across the street with another two weeks of inventory. And, for the record, carrying your stuff across the street within two days does not count as Just in Time delivery.
Order & Cleanliness
Finally, you can look at order and cleanliness. If you have ever heard of 5S, that’s what applies here. While not a numerical measurement, try to pay attention to the following:
- Does it look orderly?
- Are the machines, parts, and tools clean?
- Are positions of parts, tools, and movable machines marked?
- What kind of signs and markers can you see?
- Are there standard operating procedures on the machines? All of them?
Looking for these kinds of things gives you an impression of the order in the plant. However, since it is not a numerical measure, you would have to compare it with your experience from previous plant visits. Again, for a best of bench(mark) comparison, take a tour of a Toyota group plant.
If you’re interested in product quality, there are also a few things you can pay attention to:
- With regard to inventory, are there any blocked stocks or stocks that are not to be used for quality or other reasons? Again, look for the red stickers! Similarly, look for the reject bins. How full are they? How often are parts discarded?
- How are the products treated? Are delicate parts banged around on a forklift?
- Cleanliness on the product itself: Does it look clean? Are there, for example, metal chips on a part that may later damage an internal valve? Are there oil stains where there shouldn’t be stains?
- Do the machines look clean and operate smoothly? Toyota legend Taiichi Ohno tells a story of visiting a potential precision tool supplier only to find that the supplier was located under a train overpass, with everything vibrating whenever a train passed over. Or, in a modern sense, is there a two-hundred-ton press next to the precision milling machine?
You can also look at documentation. Try to find the quality metrics. Most plants have them, usually at the most important stations. How good are they? Of course, keep in mind that you’re looking at a measurement made by someone else and that the definition of what constitutes a problem versus what is “normal” may surprise you. If you’re not sure, assume the worst.
You can also check the manufacturing standards:
- As above, are there standard operating procedures on the machines? All of them?
- What is the date on the standard? Anything beyond six months is questionable, anything beyond one year is next to worthless.
- Do operators follow these standards?
- Look into a standard. Do you understand it? Does it seem easy to follow, clear, concise, and complete?
To judge the teamwork, have a closer look at the team meeting corner:
- Is there a team meeting corner?
- What documentation is there?
- Are there KPIs measured? What KPIs? Are these done by hand or printed out (a sure sign that workers are not involved and don’t care about the measurement)?
- Are there problem-solving sheets?
Overall, there a lot of things you can pay attention to. Just make sure you don’t overdo it. Like the young tiger hunting for ducks, if you try to catch them all, you’ll get none. Clearly decide on your focus area and then stick with it. Alternatively, if you’re part of a bigger group, spread the responsibility. Have one person look at workers, another one at machines, and so on.
And finally, read my next post on how visitors on a plant tour are manipulated, and what you can do to see through the ruse.