Baka-Yoke
In Japanese, the word "Baka" literally means crazy or stupid. I learned this term while riding on subway trains to work in Japan and older people would always mutter "Baka-mitai" at a situation or me. "Yoke" is like "preventing".
So, Baka-Yoke means "preventing stupid". This concept was developed by Dr. Shigeo Shingo and helped bring lean manufacturing to a reality. Some examples of Baka-Yoke would be not allowing a car to shift out of park without the key in the ignition or circuit breakers that pop to prevent an over-current condition that may lead to a fire because someone put too many fixtures in one circuit.
Now think about how God uses this tool in everyday life. When you are about to do something "stupid" your conscience comes into play saying, "don’t do that." Or, you just watched T.V. all day and your conscience comes and tells you "you are a lazy bum, don’t you feel horrible about yourself?"
This reminds me of a cute story on why Baka-Yoke was changed to Poke-Yoke:
One day Dr. Shingo was explaining Baka-yoke on the factory floor. A young woman started to cry. "Why are you crying?" He asked. "Because I am not a fool," she answered. "I am truly sorry." And at that exact moment, he changed the name from Baka-yoke to Poka-yoke, mistake-proofing devices.
In manufacturing, Poke Yoke is used with every machine and process of a lean factory. An example in manufacturing is through sensors, a machine will show a red light if a worker does not tighten a bolt correctly and if not corrected in a predetermined amount of time, the line will stop. Jidoka is the cousin to Poke Yoke, and helps with quality in a manufacturing line by not allowing a mistake to continue downstream until its remedied. In the Toyota Production Line, Jidoka is performed by having workers pull a stop assembly line cord that stops production until the defect is fixed.
One Piece Flow
One Piece Flow is the goal of every industrial/manufacturing engineer when designing a lean manufacturing facility. It is a method to reduce inventory and instead of producing to a forecast, you produce to actual orders. Now, one-piece flow is extremely advanced and does not happen overnight. It is the culmination of many other lean processes but is not difficult to achieve if planned for correctly.
How it works - There is one manufacturing line that has many cells, which have parts in bins (Kanbans) waiting to be manufactured into a working component. There is normally a small finished good inventory waiting to be shipped for orders. When an order comes and a component leaves its position, it triggers the manufacturing process to fill that empty position. So, the last step takes the material and component from the next to last step and manufactures a finished product to be placed in the empty spot. This process goes all the way upstream until all the empty slots are filled. The production line only makes enough to fill the next spots opening.
The part that can help make this happen is balancing a line so the longest cycle time phases finish at the same time as the short cycle time phases by creating more machines or adding more workers. Basically, if cycle time for every operation in a complete process can be reduced to equal takt time, products can be made in single-piece flow
A true One Peirce Flow is rare because there will always be some type of hybrid that allows for Economic Order Quantity in it because having a small safety stock is needed due to machine failure or other unforeseen things that may happen to the line. Sometimes one-piece flow is better accomplished through the CONWIP method (I will explain that in a future blog if I get enough interest)
There are many calculations (measures) that I will be more than happy to go over with you to make sure your line is moving efficiently and achieving One Piece Flow goals.
One very important area that will help achieve one-piece flow is Total Production Maintenance (TPM) and setting up Key Performance Indicators (KPI). This is something I will go over in my next blog!
Remember if you have any questions you can write in the comment box below or you can e-mail me and I will be sure to get back to you. Now it is time to explore Mid-town!
Next Blog: Total Production Maintenance, Ja Mata Ne!
