What is SMED?

Introduction

The SMED (Single-Minute Exchange of Dies) method is an approach designed to reduce the changeover time in industrial processes. By optimizing transitions, it directly contributes to improving the OEE (Overall Equipment Effectiveness) . This article explains this method in detail, its key steps and its benefits for manufacturers.

What is SMED?

SMED (Single-Minute Exchange of Dies) is a Lean method designed to minimize downtime during tool or production changes . It is based on a structured approach to separate and optimize internal tasks (performed while the machine is stopped) and external tasks (performed while the machine is running). Developed by Shigeo Shingo in the 1950s, this method has revolutionized industrial processes by allowing companies to gain speed , efficiency and flexibility in an increasingly demanding context.

The key stages of SMED

The implementation of the SMED method is based on four stages:

1. Analysis of the current process

The first step is to observe and measure change times as they are currently being performed. This involves detailing each task performed during the change process, distinguishing between necessary tasks, unnecessary tasks, and tasks that can be improved. The goal is to understand where inefficiencies lie and prioritize optimizations.

2. Separation of internal and external tasks

It is essential in the analysis to distinguish internal tasks (those that require stopping the machine) from external tasks (those that can be performed while the machine is running). For example, preparing tools before stopping the machine is an external task.

3. Converting internal tasks to external tasks

This step involves transforming as many internal tasks as possible into external tasks. This may include preheating tools or preparing raw materials upstream.

4. Improvement and simplification of tasks

Finally, the remaining internal tasks are analyzed to be optimized and standardized. This may include the use of specific tools or approaches such as 5S , Kaizen , PDCA , the reduction of travel or the implementation of more efficient procedures.

Concrete examples of SMED application

Applying the SMED method can transform a plant’s performance. Take a plastics company for example: before implementing SMED, mold changeovers took an average of 1 hour. By analyzing processes and converting internal tasks into external tasks, changeover times were reduced to 12 minutes, improving machine OEE and reducing inventory.

Common mistakes to avoid with SMED

Although SMED is an effective method, its application can be hampered by some common errors:

Lack of follow-up of results

Implementing SMED without measuring the gains achieved can limit its impact. It is important to continuously monitor performance indicators, such as tool changeover time or TRS/OEE , to assess progress.

Lack of team involvement

SMED requires the involvement of operators in this process, as they are the ones who make the tool changes. A lack of training or communication can lead to resistance to change.

Neglecting initial process analysis

Unconstructive analysis can lead to ineffective improvements. It is important to carefully observe each step of the process and measure task duration to identify optimization opportunities.

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