Today, our lives are becoming much easier because the user interface to technologies is improving rapidly. But what about the user interface inside factories and operations?
What are some of the fundamental philosophies to think about?
1️⃣ Accomplishing Jidou-ka, separating man & machine’s work
2️⃣ Eliminating waste on human & machine
3️⃣ Flow-friendly design
There are several points to think about.
1️⃣ Material loading & unloading points
These are locations inside the machine where you load and unload the material. When these two points are the same, an operator must unload and load the material, causing a zig-zag motion. This will become a wasted motion.
Separating these two points allows an operator to work in one smooth loading flow. This should be accomplished without additional technology, such as a robot, but by using the machine's motion or gravity.
2️⃣ Switch
Most switches are fixed without considering the work. Also, many require multiple touches to operate. Consider implementing a whisker switch with a flexible position, with its location adjusted to an operator's standardized work.
The above points should be carefully designed along with the worker's movement and flow.
🧍🏻 Human movement
Machine interfaces should respect the motion of human work. For example, a vertical safety curtain forces the operator to move around, while a horizontal safety curtain allows the operator to move to the following process. Such differences have a significant impact on the motion.
→ Flow
Different technologies should be connected to create flow. However, various technologies have different interfaces, making it challenging to create flow. For example, one eject part is from the right, and the other is from the left. Standardizing such design helps create flow.
Perhaps the most important thing to consider is separating man's and machine's work. The worker should not need to stare while the machine works. One idea is to keep the automatic machines away from operators' movement. Collect and connect all human work with a U-shape conveyor, isolating the automatic machines.
Another important topic to consider is incidental work. A project to improve standardized work in a traditional job shop implemented “fully” automated machines, but an operator could not handle more than two machines. We discovered the following incidental works an operator needs to perform on each machine.
[Tool change]
Tool 1 = every 50 pieces
Tool 2 = every 75 pieces
Tool 3 = every 80 pieces
Tool 4 = every 115 pieces
Tool 5 = every 130 pieces
[Material change]
Every 77 or 113, depending on the product
[Defect]
☑️ Remove one piece
Due to such random frequencies of incidental work, operators could not handle more than two machines. Costly “fully” automated technologies were used, but the results were not necessarily productive since there were no philosophies on designing incidental work.
These rules on design philosophies are what make TPS highly productive. For example, the shift break and maintenance are carefully designed for both activities. Shift breaks are designed every two hours, so engineers must create a machine that can run stably for those hours. On the other hand, they don’t challenge a machine to run one week without any maintenance and expect it to be stable.
When it comes to machines, we respect the engineering or science behind them. Yet, just like any technology in the real world has some rules, machines inside plants must also have one to provide high performance. Many TPS principles, such as build-in quality and one-by-one continuous flow, are guiding rules. When we apply these rules, we usually discover new science.
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