5 Indispensable Continuous Improvement Tools for Your Factory

Continuous improvement (CI) is an essential component of lean manufacturing. It is an ongoing effort that aims to detect and resolve problems, thereby optimizing uptime and efficiency. Although implementing CI in your factory is undoubtedly beneficial, going about it in an unsystematic way can be inefficient, as you might not be targeting your biggest losses.  

Continuous improvement tools assist in making the CI process structured, fast, and effective.There are myriad techniques to pick from. Choosing the right ones can therefore be difficult, as it is easy to get lost in details, and not see the forest for the trees.

Let’s explore five excellent continuous improvement tools that are of great help in a factory environment:

1. Kaizen

A Kaizen event is a brainstorming session where operators can share their perspective on improving a process. The great thing about Kaizen, is that its success depends on the involvement of a wide variety of people, ranging from upper management to maintenance and machine operators. A problem is thereby encapsulated in its fulness, making it clear what steps should be undertaken toward an improvement.

Continuous Improvement Tools - Kaizen Methodology

The technique that is used at Kaizen events is called the PDCA cycle (also known as the Shewhart or Deming cycle), which consists of four steps:

  • Plan: define the goal and the action to be taken toward its achievement
  • Do: perform the measures from the previous step
  • Check: evaluate the results
  • Act/adjust: implement a solution

Gradually, the composition of the operator involved in Kaizen sessions will change. It might turn out that a problem has to do with a machine, making the involvement of operators from Planning redundant, and necessitating the expertise of a technical specialist.

Kaizen Pros:

  • Very structured method for technical fields
  • Involves a diverse set of people
  • Works well for small to medium-sized problems
  • Results can be standardized and shared across plants

Kaizen Cons:

  • Can’t be used when doing investigative research
  • Doesn’t work well for larger problems

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2. The 4Ms

The 4Ms method is used to prevent tackling a problem in a haphazard way. There are different kinds of losses in a factory, and it is not always apparent what cause underlies them. There might be an issue with the packaging material, but the cause could just as well have to do with the machinery.

Continuous Improvement - The 4Ms

This continuous improvement tool gathers information about an issue by dividing it into four categories: manpower, machinery, materials, and method. A brainstorming session can then be organized in which operators pitch ideas about possible causes. These ideas are entered under their respective categories, creating a concrete visual representation of the problem at hand.

The 4Ms Pros:

  • Facilitates brainstorming about complex problems
  • Categorical way of thinking about possible causes

The 4Ms Cons:

  • Can only be used in factories
  • Not an entire solution, but part of a larger process

3. Spaghetti Diagram

The Spaghetti Diagram helps improve processes on the factory floor by tracking the movement of operators. You can easily make a Spaghetti Diagram using a pen and paper, although a tablet device can also be used. This method consists of observing an operator while they work, and then drawing their movements on a map.

CI Tools Spaghetti Diagram

You can now see how many times a worker is at a machine, which path they took to that machine, and so on. Managers now use the Spaghetti Diagram to think about streamlining the way in which work is done on the factory floor. The great thing about this method is that you can reuse it to view the effected improvements.

Spaghetti Diagram Pros:

  • Easy-to-use
  • Creates a visual overview of possible issues

Spaghetti Diagram Cons:

  • Can only be used to track physical movement

4. SMED

SMED (Single-minute exchange of dies) is a continuous improvement tool that helps reduce the amount of downtime during a changeover. By surveying all the activities during and outside of downtime (so-called internal and external activities), a path is opened by which you can apply improvements. Certain internal activities can possibly be changed into external activities, resulting in less downtime.

CI Tools Smed

A SMED can be performed by following these steps:

  1. Identify all activities within a certain area
  2. Divide internal from external elements
  3. Convert internal activities into external activities
  4. Streamline the remaining external activities

Before applying this method, you need to make sure that a changeover is causing a significant amount of losses. One way to figure this out is by using a Root Cause Analysis tool like the Pareto Chart. If changeovers aren’t causing losses, it is better to not apply this method.


SMED Pros:

  • Reduction of downtime, changeover time, and money-loss

SMED Cons:

  • Using this method can be time-consuming, as there are lots of sub-activities to improve
  • Only applicable if changeovers cause significant losses

5. Gemba Walks

Gemba walks are an integral part of lean management. This continuous improvement tool comprises of a manager or director walking around the factory to ask workers about the problems relating to their work. Gemba walks are performed using a checklist, but can be intuitively done as one becomes experienced doing them.

Visual Gemba Walks

Operators might be wasting time by working in a certain way, or, on the contrary, be more efficient by diverting from instructions. Managers can take this information into account, and take steps toward implementing an improvement. It is important that operators not be approached in a confrontational, but in a cooperative manner. This way, workers feel heard by management, and the connection between the two is strengthened.

Gemba Walks Pros:

  • Improves communication between operators and upper management
  • Keeps upper management in touch with what’s happening on the factory floor

Gemba Walks Cons:

  • Can be easily forgotten to do

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