Tag Archives: Pull

Pull is control based on actual need in the near future. A pull system sets limits on the amount of work, which is a push system does not.

What is Lean?

What is lean? I would like to answer that question with an explanation based on the description given by the inventor of lean, Taiichi Ohno.

Pull and push

Hopp and Spearman define pull in their work Factory Physics based on Little’s law. It’s a good definition that states that pull sets limits on any current workload while push doesn’t. However, there’s more to lean than pull.

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Visual Management

Visuell styrning sänker osäkerheten.A lot of people who have worked with projects have experienced the same thing: downtime. You have to wait for people to get back to you, wait for results and wait for decisions to be made. On top of that other actors are waiting for you to finish your task that you can’t finish because you’re waiting for something or someone.

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Leveling Workflow

Leveling workflow means that a limit is set for the number of tasks being done concurrently and that everyone helps each other out.

It’s common knowledge that traffic jams and congestion appear when there are more cars on a road than it’s been built for. In the same vein, having more work without the capacity to handle it leads to a kind of traffic jam within an operation. Overloading causes long lead times and a low throughput. It also causes disruptions that hinder cooperation, causes stress, puts quality at risk and generates waste. To avoid overloading a system it’s necessary to consider the current inflow and adjust it to the capacity and equalize the workflow over time and between individuals to avoid local overload. Equalizing the workflow is not trivial when there is a mix of different kinds of work to take care of. Even if measures are taken to balance the inflow there will still be tasks that are more time-consuming and may stop workflow in different areas.

Leveling Workflow – Helping Each Other Out

In the clip below an example of leveling  the workflow is demonstrated using a simulated product assembly that has been divided up into different steps. The clip features students from the  Technological University of Pereira, Colombia.

How did the equalization take place? The assemblers moved up along the assembly line every time they were a bit ahead. By doing this they could help assemblers’ upstreams and take over earlier stages when the product became more advanced and demanded more time. This way of working assumes that the workers know several stages of the production. They can enter the flow earlier and help out.

What relation does this have to projects? Projects usually involve collaboration between people from different professions. In product development there are designers, testers, purchasers, product technicians, people in logistics and marketers. In order to reach the goals of the project they need to collaborate. In practice some of the participants are always overloaded. Who they are varies over the project’s life cycle, which makes the total available resources in theory correct. The problem is that the resources aren’t used optimally when a large part of the project group is waiting for one member to finish their tasks. For the staff with extra time it’s often natural to start with the next stage of the project. The consequence of this is that interaction within the group is reduced which leads to an increase in waste.

Working Together Within a Project

So what should be done to equalize the workflow within a project? Firstly, don’t jump ahead and start working on stages later in the flow. Instead, make sure to finish the current stages. This means helping each other out. For example, if the designer is stuck on a design problem then other engineers and technicians in the project group should help out. This type of collaboration within a project assumes that a person is able to and ready to learn several stages/parts of the project. People need to let go of the idea of specialization and defined roles since it inhibits collaboration, learning and efficient use of resources.