SMED: How to Design Machines for High OEE

Single-Minute Exchange of Die (SMED) is a method developed by Shigeo Shingo to significantly reduce the time needed for machine and equipment changeovers in production. Shortening this time directly increases machine availability, which is a key factor in production efficiency. In this article, we discuss how to design machines in line with SMED principles.

Lean Manufacturing Principles

Lean Manufacturing Fundamentals

Lean Manufacturing is a production management philosophy aimed at maximizing customer value while minimizing waste. Lean focuses on continuous process improvement and the elimination of unnecessary activities, leading to higher efficiency and lower production costs.

Key Lean Tools

Lean Manufacturing uses many tools to help achieve these goals. They include:

• Kaizen: a continuous improvement method that involves all employees in improving the company’s operations.
• 5S: a workplace organization system based on sorting, systematizing, cleaning, standardization, and self-discipline.
• Just-In-Time (JIT): a production system in which materials and components are delivered exactly when needed, minimizing inventory.
• SMED: a key Lean element focused on rapid machine changeovers, enabling a flexible response to changing production needs.

SMED – Single-Minute Exchange of Die

Definition and Principles of SMED

Single-Minute Exchange of Die (SMED) is a method introduced by Shigeo Shingo to drastically reduce the time required for machine and production line changeovers. The main goal of SMED is to reduce changeover time to a single-digit number of minutes (under 10 minutes). There are several key SMED principles:

1. Separating internal and external activities:
   • Internal activities are those that can only be performed when the machine is stopped.
   • External activities are those that can be performed while the machine is running.
   • The first step in SMED is to identify and convert as many internal activities as possible into external ones.
2. Standardizing and simplifying internal activities:
   • Standardizing tools and working methods so that all operations are carried out in the same way.
   • Simplifying and speeding up activities that must be performed while the machine is stopped.
3. Implementing quick-clamping systems:
   • Using systems that allow tools and machine components to be mounted and removed quickly.
   • Using quick-release elements that minimize the need for adjustment and calibration.
4. Training and involving employees:
   • Training machine operators and production teams in new SMED procedures and techniques.
   • Involving employees in the improvement process and in identifying further opportunities to reduce changeover times.

SMED Implementation Process

SMED implementation can be divided into several key stages:

1. Analyzing the current changeover process:
   • Carefully monitoring and documenting all activities related to changeovers.
   • Identifying internal and external activities and their duration.
2. Converting internal activities into external ones:
   • Assessing whether internal activities can be shifted to external ones.
   • Implementing new procedures that allow more activities to be carried out while the machine is running.
3. Optimizing internal activities:
   • Standardizing and simplifying internal procedures.
   • Introducing quick-clamping systems and tools.
4. Training and employee involvement:
   • Providing training for operators and production teams.
   • Encouraging active participation in the improvement process.
5. Monitoring and continuous improvement:
   • Regularly monitoring results and changeover times.
   • Implementing employee suggestions and looking for further improvements.

Examples of Successful SMED Implementation Across Industries

Implementing SMED has delivered significant benefits in many manufacturing sectors:

• Automotive industry:
  • In car manufacturing plants such as Toyota, the use of SMED has significantly reduced changeover times, contributing to greater production flexibility, faster introduction of new models to the market, and improved production efficiency.
• Food industry:
  • In food manufacturing companies such as Nestlé, SMED has enabled rapid changeovers between different products on production lines, reducing downtime and increasing production efficiency.
• Electronics industry:
  • In plants manufacturing electronic equipment, SMED has made it possible to adapt production lines more quickly to different product batches, helping companies stay competitive in a fast-moving market.

Production automation and SMED

The role of automation in SMED

Automation plays a key role in reducing changeover times, which is the core objective of SMED. Modern technologies and automation solutions make it possible to speed up many processes that were previously performed manually and required significant labor and time. Automation can support SMED in several key areas:

1. Fast tool clamping and release:
   • Automatic tool clamping systems can significantly reduce the time needed for tool changes. These systems eliminate the need for manual tightening and adjustment, which not only shortens changeover times but also reduces the risk of errors.
2. Automatic machine parameter setting:
   • Implementing systems that automatically set machine parameters in line with production requirements allows machines to be adjusted quickly and accurately for new tasks. This avoids manual programming and minimizes setup errors.
3. Robotics and automation of auxiliary processes:
   • Using robots for repetitive and time-consuming tasks, such as feeding and unloading materials, can significantly speed up the entire changeover process.
4. Real-time monitoring and data analysis:
   • SCADA (Supervisory Control and Data Acquisition) systems enable ongoing monitoring and analysis of production processes. This makes it possible to quickly identify and eliminate bottlenecks and optimize changeover processes.

SCADA systems and their impact on SMED

SCADA systems play an important role in monitoring and optimizing changeover processes within SMED.

SCADA enables real-time collection and analysis of data from machines and production processes, which is critical for fast and effective changeovers.

1. Monitoring changeover times:
   • SCADA makes it possible to track changeover times accurately, helping identify areas that require optimization. With precise data, improvement decisions can be made more effectively.
2. Downtime cause analysis:
   • SCADA systems can record and analyze the causes of downtime, allowing problems to be identified and eliminated quickly. This helps minimize downtime and increase machine availability.
3. Integration with ERP and Manufacturing Execution Systems:
   • Integrating SCADA with ERP (Enterprise Resource Planning) and Manufacturing Execution Systems enables comprehensive management of production processes. This improves changeover planning and coordination, which helps increase production efficiency.

POKA-YOKE – quality assurance

Definition of POKA-YOKE

POKA-YOKE is a Japanese error-proofing technique based on designing production processes so that mistakes are either impossible to make or easy to detect and correct. This technique is used to eliminate defects and improve product quality.

Purpose and principles of POKA-YOKE

1. Error prevention:
   • The main goal of POKA-YOKE is to eliminate errors already at the production process design stage. This helps avoid costly rework and downtime.
2. Error detection and correction:
   • Where errors cannot be eliminated completely, POKA-YOKE ensures they are detected and corrected quickly before they affect the final product.
3. Simplicity and effectiveness:
   • POKA-YOKE solutions should be simple and easy to implement so they can be used effectively by production line operators.

Examples of POKA-YOKE applications in manufacturing

• Automotive industry:
  • In car manufacturing, various POKA-YOKE solutions are used, such as sensors and indicators that prevent parts from being assembled in the wrong sequence or with the wrong force.
• Electronics industry:
  • In the production of electronic components, POKA-YOKE may include special connectors and fixtures that ensure correct connections and eliminate the risk of assembly errors.
• Food industry:
  • In food manufacturing plants, POKA-YOKE may include sensors that detect foreign bodies in products, ensuring compliance with quality and safety standards.

The impact of POKA-YOKE on SMED

1. Reduction of production defects:
   • With POKA-YOKE, changeover processes can be designed to minimize the risk of errors, resulting in higher product quality and a lower risk of downtime.
2. Improved process reliability:
   • Using POKA-YOKE in changeover processes increases the reliability and repeatability of these operations, which is crucial for effective SMED implementation.

TPM (Total Productive Maintenance) and SMED

What is TPM?

Total Productive Maintenance (TPM) is a comprehensive maintenance approach that engages all employees to maximize equipment effectiveness.

TPM includes various activities such as preventive maintenance, autonomous maintenance by operators, and continuous process improvement.

Pillars of TPM

1. Autonomous maintenance:
   • Operators are responsible for the daily upkeep of machines, including cleaning, lubrication, and minor repairs. As a result, machines remain in better condition and break down less often.
2. Preventive maintenance:
   • Regular inspections and servicing prevent unexpected failures and extend machine life.
3. Continuous improvement:
   • Ongoing efforts to improve equipment efficiency and reliability through data analysis and the implementation of innovative solutions.

How TPM affects machine availability

TPM significantly improves machine availability, which is one of the key OEE metrics. Regular maintenance and operator involvement in servicing activities minimize downtime and failures, enabling smooth, uninterrupted production and improving production efficiency.

SMED as part of TPM

Single-Minute Exchange of Die (SMED) is a method introduced by Shigeo Shingo to drastically reduce the time required for machine and production line changeovers. The main goal of SMED is to reduce changeover time to a single-digit number of minutes (under 10 minutes). There are several key SMED principles:

1. Reduction of changeover times:
   • With SMED, the time needed for changeovers is significantly reduced, increasing machine availability and allowing more flexible production planning.
2. Greater operator involvement:
   • Operators responsible for autonomous maintenance are also involved in changeover processes, which leads to a better understanding of the machines and better procedure optimization.

Key performance indicators (KPI) and SMED

Introduction to KPI

Key Performance Indicators (KPI) are tools used to measure and monitor the effectiveness of production processes. In the context of SMED, the most important KPIs are:

1. Changeover time:
   • The time required to complete a machine changeover, which directly affects production availability and flexibility.
2. MTBF (Mean Time Between Failures):
   • The average time between failures, indicating machine reliability and the effectiveness of maintenance activities.
3. MTTR (Mean Time To Repair):
   • The average time needed to repair a machine, which affects downtime duration and machine availability.

Monitoring KPI in the context of SMED

Effective monitoring of KPIs related to changeover times is essential for optimizing SMED processes. This includes:

1. Regular data collection:
   • Data on changeover times, failures, and repairs should be collected and analyzed regularly to identify areas that require improvement.
2. Analysis and reporting:
   • Data analysis makes it possible to identify trends and patterns that may indicate potential problems or opportunities for optimisation. Regular KPI reporting supports informed decisions on improvements.
3. Use of IT systems:
   • IT systems such as ERP and manufacturing execution systems can support KPI monitoring and analysis by providing accurate, up-to-date data on production process performance.

Use of IT systems in KPI monitoring

• ERP systems:
  • ERP systems enable centralised management of production data, allowing better planning and control of changeover processes.
• Manufacturing execution systems:
  • Manufacturing execution systems enable ongoing monitoring of production processes and an immediate response to any issues. This makes it possible to quickly identify and eliminate the causes of downtime.

FAT and SAT testing in relation to SMED

Definition of FAT and SAT

Factory Acceptance Test (FAT) and Site Acceptance Test (SAT) are key tests carried out before new machines or production lines are implemented.

1. FAT (Factory Acceptance Test):
   • A test performed at the manufacturer’s facility to confirm that the machine meets all specifications and requirements before it is shipped to the customer.
2. SAT (Site Acceptance Test):
   • A test performed at the customer’s site after machine installation to confirm that the machine operates correctly under actual production conditions.

The importance of FAT and SAT testing in the context of SMED

1. Verification of functionality:
   • FAT and SAT tests make it possible to verify whether the machine meets all requirements and is capable of carrying out changeovers in line with SMED principles.
2. Optimisation of settings:
   • During testing, the necessary calibration and adjustments can be made to achieve optimal changeover times.
3. Operator training:
   • FAT and SAT tests also provide an opportunity to train operators in the use of new machines and SMED procedures, ensuring smooth implementation of new production processes.

Summary of the article’s key points

Machine design that takes SMED principles into account is essential for achieving high production efficiency and minimising changeover times. In this article, we discussed how SMED fits within Lean Manufacturing principles, how production process automation and SCADA systems support SMED, and how POKA-YOKE, TPM and KPIs can contribute to successful SMED implementation. FAT and SAT tests also play an important role in verifying and optimising changeover processes.

The future and development of technology in the context of SMED

New technologies such as advanced automation systems, artificial intelligence and the Internet of Things (IoT) will play an increasingly important role in the further optimisation of SMED processes. Companies seeking a competitive advantage should invest in these technologies and continuously improve their production processes in line with SMED principles.