Waiting – a Lean waste to eliminate

Lean Manufacturing is a system that aims to eliminate waste. Each production process consists of activities that add value to the product. These are known as VA (Value Added) and activities that do not add value – NVA (No Value Added). Customers do not want to pay for activities that do not add value to the product, so every company should focus on eliminating them.

Identification of waiting Lean waste

Waiting – that is, wasting time

We define all wastes that occur in production, logistics or service processes as time waste. We can categorize waiting Lean wastes into three basic categories:

1. The first category of waiting – when a person waits for a machine.
2. The second category is when a person waits for another person.
3. The third category – when a person waits for material.

A person waits for a machine

The first category of waste is when a person waits for a machine, will be encountered in processes where a machine is operated by an employee. In this case, the operator is dependent on the machine’s cycle time. The role of the person optimizing such a workplace is to analyze whether, during the machine cycle time, the operator can perform another activity foreseen in the process.

An example might be to pick up components for assembly or perform a visual inspection of a completed operation, as provided in the process. In such a case, the time of all activities performed by an employee should be measured and the operator’s work standard should be developed using the Yamazumi chart. It may also happen that the waiting Lean waste is replaced by walking, for example. If the Takt Time required on the line allows this, the operator will operate two machines between which he will have to walk.

A person waits for another person

The second category – when a person waits for another person – this type of waiting will be encountered in processes when the line is poorly balanced. That is, when there is a difference in cycle times at individual workstations. With a poorly balanced line, we will see operators working at stations with short cycle times waiting for material from stations where the cycle time is longer. A person who wants to optimize such a process needs to measure the times of the operations performed at each workstation, and record the results. Then a Yamazumi chart should be made, where one can see which operations in the process are too long and which have short cycle times in relation to the required Takt Time (TT). If possible, these operations should be balanced improving the balance on the line.

A similar example to the one described above will be the case when a person who has not worked on the line before comes to the line. Lack of familiarity with the process will cause that person to slow down the process until he becomes proficient and confident. In that case, the next operator, working at the next station, will be waiting for the material to come in so he can do his job.

A person waits for material

The third category is a situation in which a person waits for material. These are moments during which internal logistics will not deliver components on time. Then, due to the lack of material, the production line is stopped and the waste called waiting will occur in the process until the material is not delivered to the line.

Reduction of waiting

What can we do to reduce waiting? Several lean tools come to rescue.

A huge role in reducing waiting is played by the 5S system in an organization. By implementing this system consisting of 5 steps – selection, systematics, cleaning, standardization and self-discipline – you can reduce the amount of time wasted searching for the tools, documents or instructions needed for work. A well-organized workstation according to the requirements of the 5S methodology allows operators to work safely with ergonomic principles.

Another tool, the use of which allows to reduce waiting time, is SMED. SMED is a tool the application of which makes it possible to reduce changeover times. A well-conducted SMED workshop and the implementation of this methodology makes it possible to reduce changeover times even to single digits. This ultimately affects the reduction of waiting for a new product to be launched on the production line.

Well-planned production, good information flow, quick solution of quality problems, well-trained staff, well-thought-out layout are other factors that reduce waiting in manufacturing, logistics and service processes.

Well-planned production, good information flow, quick solution of quality problems, well-trained staff, well-thought-out layout are other factors that reduce waiting in manufacturing, logistics and service processes.