One of the most important concepts in process improvement, cellular manufacturing involves fine-tuning an operation so that work on sub-projects within a larger project are done in close proximity.
As with many things in process improvement and Six Sigma, cellular manufacturing seems like common sense once it is understood. But many do not put the strategy into practice, leading to inefficiency and waste in a process.
An easy way to think of cellular manufacturing is that it reflects the concept of a surgical team in a hospital. The team goes into surgery with all the people and necessary equipment in one place. If a doctor needs a retractor, they don’t wait 10 minutes for it to arrive from the other side of the hospital. And if they need a surgical assistant, he or she is right there.
The impact of cellular manufacturing can prove significant, according to Patrick Davidson, MA, CSSBB.
“Designing intelligent cells reduces WIP (work in progress) by over 50%, reduces floor space utilization by over 25%, increases velocity through the value-added steps (the amount varies by organization), and increases productivity (measured in parts / person / hour) – in many cases by over 100%!,” Davidson said.
How Cellular Manufacturing Works
To accomplish cellular manufacturing, those who work on a component or sub-project within a process are grouped together in “cells” that are in close proximity. This facilitates continuous work production and allows for fast feedback between workers in each cell when problems arise.
In some cases, workstations in each cell are laid out in a U-shape. Any machinery used within a sub-project also are grouped together, as well as parts and supplies needed.
Workers within each cell are cross-trained to develop the skills needed to handle multiple tasks within their cell.
All of this creates a situation where the material flow on a component or sub-project is improved. Cellular manufacturing supports communication between workers in each cell and reduces the distance traveled by materials and inventory.
While cell layout can vary, each one is designed to address the following wastes, known as the acronym TIM WOODS:
- T – minimize the transportation distances
- I – minimize the work in process
- M – proper motions for workers
- W – minimize waiting
- O – eliminate over-production
- O – design out over-processing
- D – defects are identified quickly
- S – underutilization of skills
“By moving pieces of equipment and workstations closer together, putting them in order and in a U-shaped cell with counter-clockwise movement through the cell (beginning and ending on the aisle), we also reduce scrap and rework because any issues found at the “next operation” are right next to the supplying operation – so feedback is nearly instant,” said Davidson.
Cellular manufacturing represents a subsection strategy within Lean manufacturing or what is known as Just in Time (JIT) manufacturing. To understand the concept of JIT, it’s important to know about a trip made to Piggly Wiggly by Toyota engineer Taiichi Ohno.
When Ohno visited the grocery store in the late 1950s, he saw something that ignited a new concept for manufacturing. Customers entered the store, pulled an item from the shelf – let’s say a jar of peanut butter – and put it in their basket. The empty space on the shelf was almost immediately filled with a replacement jar of peanut butter to meet the demand of the next shopper.
And if that next shopper wanted 10 jars of peanut butter, they were there. And then the shelf would immediately be replaced with 10 more jars of peanut butter.
Ohno knew this wasn’t the case in manufacturing at the time. The separation between individual workers on a manufacturing line meant customers had to wait through a complete manufacturing cycle to get what they wanted.
Ohno decided he wanted to reduce the response time between product manufacturers and product customers. That was the seed that led to the Toyota Production System, Lean Manufacturing and JIT production.
Flexibility and Versatility
Ohno’s breakthrough required grouping people and the machines they used in one area. It also involved better communication between workers. This arrangement led to more flexibility in the manufacturing process and an improved ability to quickly create products to meet customer demand.
In short, that’s one reason why you don’t have to wait two months to get a new Toyota vehicle. It’s right there on the lot, in a variety of models and colors, ready for you to drive away.
While it has its roots in the automobile industry, cellular manufacturing can work on any type of project in any business.
Customers see an example every time they go to the grocery store. In most stores, there now are three different “cells” for customers to choose from: self-checkout, the 10 items or less line, and full service.
Insurance companies use it to group together workers in various departments such as claims, underwriting and credit. Medical facilities, such as Akron Children’s Hospital in Ohio and Vanderbilt University Trauma Center, have put the cellular strategy into use to improve patient outcomes, create better communication and make information flow smoothly.
Closer to home, a kitchen offers a classic example of how a cellular layout improves efficiency. By grouping items together needed for specific cooking tasks, making dinner gets a lot easier.
It may have started with a trip to a grocery store 70 years ago, but cellular manufacturing still proves significant today.