SMED (Single-Minute Exchange of Dies)

WHAT IS SMED?

SMED (Single-Minute Exchange of Dies) is a system for dramatically reducing the time it takes to complete equipment changeovers. The essence of the SMED system is to convert as many changeover steps as possible to “external” (performed while the equipment is running), and to simplify and streamline the remaining steps. The name Single-Minute Exchange of Dies comes from the goal of reducing changeover times to the “single” digits (i.e. less than 10 minutes).

BASICS OF SMED

SMED was developed by Shigeo Shingo, a Japanese industrial engineer who was extraordinarily successful in helping companies dramatically reduce their changeover times. His pioneering work led to documented reductions in changeover times averaging 94% (e.g. from 90 minutes to less than 5 minutes) across a wide range of companies.

In SMED, changeovers are made up of steps that are termed “elements”. There are two types of elements:

·         Internal Elements (elements that must be completed while the equipment is stopped)

·         External Elements (elements that can be completed while the equipment is running)

The SMED process focuses on making as many elements as possible external, and simplifying and streamlining all elements.

The SMED system has three major phases as shown above. These phases are performed in sequence and the entire sequence can be iterated (repeated). 

SMED is typically broken down into three stages. Each stage has specific tasks and objectives and all are inter-related and work together. Those stages are outlined below.

Stage 1 – Separate internal and external setup

Certain tasks can clearly be done before machines are stopped for changeover. These include lining up the right people, preparing parts and tools, making repairs, and bringing the parts and tools closer to the equipment. There are three practical techniques to doing this:

·    Develop and implement changeover checklists.

·    Perform function checks on parts and tools.

·    Reduce transportation or tools, parts, and materials.

By separating these tasks and performing them as external setup can cut changeover time by as much as 30% to 50%.

Stage 2 – Convert internal setup to external setup

·    Look at the true functions and purposes of each operation in your current internal setup

·    Find ways to convert these internal setups to external setup.

The key to successful implementation of Stage 2 is to look at the function as if you are new to it. Three practical techniques help shift internal setup tasks to external setup. Those techniques are:

·    Prepare operating conditions in advance

·    Standardize functions

·    Use intermediary jigs

Stage 3 – Streamline internal and external elements

In this third and final stage, all of the remaining internal and external setup operations are improved. This can be done by looking closely at each operations function and purpose one more time. More specifically, Stage 3 improvements can be divided into external and internal setup improvements. Four basic approaches to accomplishing this are through:

External Setup

·    Maintain a visual organized workplace

Internal Setup

·    Implement parallel operations

·    Eliminate the need for adjustments

·    Use functional clamps

·    Mechanize functions

SMED provides many benefits for companies and those working within the company. More specifically, the advantages of SMED along with quicker and more efficient setup times are improved flexibility, quicker delivery, better quality and higher productivity. Through these benefits you will also see simpler setups and safer changeovers, less inventory and more standardized processes.

SMED advantages

• Reduction of the number of required tools
• Reducing the required inventory
• Reducing lead times
• Improved ability to produce small batches
• Quicker response time to customer wishes
• Increase capacity
• Increase quality
• Increase flexibility
• Reduce costs and grow profits