What is One-Piece Flow?
Written by Jason Haines
“I hate wasting time or money and that happens all the time for no good reason, and then people save money by skimping on the important things,” -Rick Baker
The ultimate goal of installing Lean Manufacturing into any facility is to have no inventory and create a One-Piece Flow system that will ultimately show the respect for all people in an organization. You may never reach no inventory and full One-Piece Flow, but companies will bring a culture of respect for people in the journey to these Lean goals.
What is the opposite of One-Piece Flow? That would be batch processing. Batch processing is the process of making more than is needed or making items to early. Also known as overproduction, or the mother of all waste. In my mind batch processing is drudgery and mundane. It kills a person’s spirit and allows for no improvement. At the end of the day it causes stress because you go back to fix issues that you had no time to fix before due to being too busy being busy.
How did batch processing come about? Largely, it came about because of new machinery that wasn’t very flexible to the process of the business. The machines did what was needed, producing one part as fast as possible.
However, when needed to change over to a new part the change took hours. This is how batch processing and economic order quantity got started and the change overs were tedious and long. Both were brought about to reduce the pain of changeovers. Employees believed they couldn’t improve these changeovers, so they never challenged the process and continued to do the tedious jobs they were doing.
Then, the invention of the Lean Manufacturing philosophy disrupts this ideology. Started in Japan after WWII, Lean was designed to help revitalize their economy and make them stronger in the world with their products. Before and during WWII, Japanese products were known for low quality products that were not desired throughout the world. The Japanese accepted the help of the United States and brought what we called TWI to their country. The goal of TWI was to help companies only produce what was needed at the time and learn how to make better quality products. This is where the Toyota Production System, also known as TPS, came to fruition and fathered what we in the United States like to call Lean Manufacturing.
Some of the tools that were brought into Lean are the Single Minute Exchange of Dies, or SMED, and the creation of One-Piece Flow. In order to get closer to One-Piece Flow the Japanese realized they needed to find a way to make changeovers on machines easier, quicker, and more frequent. They accomplished this by studying all parts of a changeover and determining what types of changes they could make to the process. They worked on the process, rather than putting checks and balances on the people. While working on the process the managers decided what parts of the changeovers could be externalized and done between changeovers. They also redesigned parts for easier access and removal on the machine. These changes reduced change over times down from hours into minutes.
After the SMED changes are implemented companies can start their One-Piece Flow philosophy. One-Piece Flow is the process of having items go through the process one piece at a time. Now, this does not mean you are only making one item through the whole process, but each individual person or machine will be completing one part of the process at a time. This reduces the area that is needed within a facility, the inventory needed in a facility, and the amount of time needed to produce parts in a facility. Just in the quantity of time, a facility can save 96% of their time by implementing this process.
How can a company begin their journey with space savings, inventory reduction, and overall better flow of products? Once you have implemented One-Piece Flow you can continue your journey of continuous improvement. By making the changes to machines for quicker changeovers and seeing where you need Kanbans set up, you can keep the right amount of inventory in areas that are causing bottlenecks. These bottlenecks are the factors that you can study and determine the best way to improve the area. This will be a continual journey that challenges employees to new and better ways to do things while improving the process as a whole.
Another key to having One-Piece Flow is to know your Takt times for all your products. Takt time equals the amount of time available to produce parts divided by the demand. This time will help you know how many parts are needed to be produced in order to reach your customer demand numbers. Once an organization finds the Takt time of their products they can balance the schedule to fit the facility. This scheduling will produce product as needed to help reduce inventory, reduce lead times and reduce the amount of space needed in a facility.
Many times, leaders and managers don’t understand the benefits of Lean Management and One-Piece Flow. They believe that employees standing around are costing the company money. This is the mindset change that Lean Management is trying to help with. Showing respect for people by allowing them to utilize their minds to make improvements to their jobs. When all employees feel they have a voice, they have more of an ownership in what the company’s vision is.
Lean challenged the command and control style of leadership; believing to churn and burn to hit their numbers. This style of thinking in our leadership has caused more stress than it has been helpful. When we try to have a command and control style people’s morale becomes lower, call outs happen, and turnover is extremely high. Employees don’t address problems, working the drudgery of the issues they deal with daily, and the final product suffers. Without input from the employees there is no growth of the company.
Lean Management has a different mindset. It sets a visions and standards in an organization so people know the baseline and what is expected of them. It provides tools to guide frontline workers and leaders within the organization. These tools, like SMED and One-Piece Flow, help everyone know their responsibilities and at what time to do them. Lean takes the chaos from your facility and makes everyone’s jobs efficient and more enjoyable. It helps people build relationships with each other by opening communication and eliminating bureaucracy. It brings respect for people to the organization which benefits the frontline employees, leaders, stakeholders, and the customers. Happy employees will in turn provide happy customers.
Helping you grow your business through process improvement!!