In my last post, I started to look at factors that affect the efficiency of your line, in particular the percentage of value-added time by the operators. For this I have a good data set with fifty-three different observations. One major factor was the speed of the line. Faster lines are not only easier to optimize, but they also yield more benefit for the optimization. In this post I will look at group size, as well as comparing Japan and Germany, final assemblies with subassemblies, and passenger cars with commercial vehicles.
Efficiency
Effects on Efficiency—Takt Time
Whenever I visit a factory where manual work is done, I try to estimate the percentage of value-adding time. This brings up an interesting question: What factors do affect the percentage of value-adding time? Let’s dig through my data to see what matters.
Variable Takt at Fendt in Marktoberdorf—Part 3
This is the third post in my series on how Fendt handles its rather large variability. As mentioned before, all of their tractors—eleven different models with countless variants—come from the same assembly line in Marktoberdorf. This includes small tractors that are just barely one meter wide and huge ones as you see here on the left. Imagine assembling motor bikes, cars, and trucks on the same assembly line, and you are getting close to the variability that Fendt has to deal with. Overall, this makes Fendt in my view one of the leading plants in the world in handling variability.
Luxury Car Assembly at Audi and Daimler
Recently I had the chance to visit the high-end luxury car assembly lines of two German car makers, Audi and Mercedes, making the Audi A8 and the Maybach respectively. The feel of these plants is more about craftsmanship than mass production, quite different from “normal” cars.
How to Pace Your Assembly Line
An assembly line is a manufacturing process in which a product is built in a step-by-step sequence. One of many decisions when installing an assembly line has to do with its pacing. When should you use a pulsed line? When a continuously moving line? And when is an unstructured timing best? This post will look at the pros and cons of these options.
Keep Calm and Stop the Line—Part 2
In manufacturing, a common sentiment is that the line (or generally the process) must run. There is some truth to that, but—counterintuitively—for a system to run well you need to know when to stop it too. This is my second post in a series giving you an overview on when it may be better to stop the line rather than keeping it running (and making everything worse). Keep on reading!
Keep Calm and Stop the Line—Part 1
In industry, I often find the view that machines must run. The reasons given for this are that the machines were expensive investments, labor cost will accumulate, and the customer is waiting for products, hence the line must run. There is definitely some truth in this. However, the conclusion that the line must not stop is completely wrong. On the contrary, for the line (or the process in general) to run well, you MUST stop the line in certain circumstances. In this and the next post I would like to look in more detail at when you, rather than pressing forward with production (or rather, your operators), should stop the line. Let me explain.
Ramp-Up and Ramp-Down of Production
In my last post I looked at the preparations for a proper ramp-up or start of a machine or process. This post is the second part where you actually press the button and start the machine. I will also discuss the ramp-down procedures, as well as a SMED-like approach to improve the ramp down and up again process.