Standing Vs Seated Workstations in Lean Cells?

During the summer, I am consulting a company in lean manufacturing aspects. Currently I am working on creating “flow” in one of the assembly lines of the company. Yesterday, while finalizing the details of workstations in the assembly line, I was asked this question. Here are my two cents on this issue.

One of the most debated aspects of lean approach to assembly cell design is the requirement they be chair-free—that the assemblers stand rather than sit. In lean manufacturing the concept of standing workstation is popular. Given the choice between standing and sitting most people would prefer to sit.

There are numerous applications where standing is the preferred working posture, as opposed to sitting.

• Standing is preferred when the work area is too large. The maximum reach envelope when standing is significantly larger than the corresponding reach envelope when sitting. Have you ever seen a sitting workstation for checkout cashiers in stores like Wal-Mart? Do you ever cook on a sitting chair? Large work areas frequently are found in assembly environments, including auto assembly, packaging, welding, sheet metal, and paint lines. This also applies when the person works in more than one workspace to perform his/her job duties. In lean cells you want people to move frequently so that you can achieve “self-balancing” of the cell.


• Standing is preferred when the work surface obstruction does not allow the person to comfortably position his/her legs under the surface. This is often the case when working on a conveyor, using a workstation with a drawer located underneath the work surface or a wide front beam, or using specialized equipment.


• Ergonomics research shows that standing is recommended to maximize grip forces, and improve static or dynamic lifts. In general, more strength can be exerted while standing.

There is also an extensive lists of jobs that are most appropriately done standing, including construction workers, highway flaggers, medical personnel, painters, electricians, plumbers, loggers, firefighters, plant inspectors, and maintenance personnel.

Applications where seated workstation is preferred.

• Work that is highly dependent of fine motor functions—manual electronic assembly like soldering, writing, and sewing etc should be done at a seated workplace equipped with armrests.


• Work that require precise foot control movements.

Remember assembly and manufacturing line working requirements are different from the work requirements of office desks. The short term comfort of sitting does not translate to long-term well-being but instead leads to weight and back problems. In most of the manufacturing and assembly line scenario it is often un-ergonomic to perform your job while seated. From a strictly ergonomic standpoint sitting all the time is in fact no better than standing all the time.

So the rule of thumb…Use seated workstation only when fine motor skills are essential.

What is Lean Thinking?

John Krafcik, an MIT MBA student coined the term “Lean Manufacturing” to identify the Toyota methods, because the production system achieved more results with less resources. TPS, or lean production, was an after-effect of the competition in the Japanese automobile industry after World War II. The mass production techniques pioneered by Henry Ford were unsuitable for low volume production, so Toyota found it necessary to develop its own production system to build cars more cheaply with inbuilt quality. In essence, Lean production is the elimination of waste to produce more flexible and adaptable manufacturing processes. Lean Thinking extends lean production to go beyond manufacturing and to include the entire enterprise. Lean thinking extended the elimination of waste to include the creation of value at enterprise level.

This business philosophy goes by different names. Agile Philosphy, Just-In-Time (JIT), Synchronous Manufacturing and Continuous Flow are all terms that are used in parallel with lean thinking.The basic components and tools of the Toyota Production System (TPS) and lean production existed in literature much before publication of The Machine That Changed The World (Womack, et al., 1990). However advent of this book popularized the Lean concept and brought the ideas to masses. The key idea in the book (and one that is absent in earlier literature) is that of “Value.” Specifying value from customer's perspective (whether internal or external) is an important step in lean thinking. Lean thinking focuses on abolishing or reducing waste (or “muda”, the Japanese word for waste) on maximizing or fully utilizing activities that add value from customer’s perspective.

Value-Added: An activity that changes the size, shape, fit, form, of function of material or information to meet the customer requirement. The customer is willing to pay for it.

Non-Value-Added: Activities that take time and resources but do not add to customer requirements.

The value stream represents the end to end processes through the entire enterprise. The lean thinking focuses on every facet of the value stream by eliminating waste in order to reduce cost, generate capital, bring in more sales, and remain competitive in growing global market.