What is SMED?
SMED Definition:
SMED stands for Single-Minute Exchange of Die. It is a Lean manufacturing technique aimed at reducing the setup or changeover time required to switch a production line from manufacturing one product to the next. The term “single-minute” does not necessarily mean that every changeover will take exactly one minute, but rather emphasizes the goal of achieving rapid, efficient setups in the shortest possible time (refers to single digits, specifically less than 10 minutes).
SMED focuses on identifying and eliminating non-value-added activities during the changeover process, streamlining procedures, and standardizing tasks to minimize downtime and increase overall equipment effectiveness (OEE). By implementing SMED principles, companies can significantly reduce setup times, increase production flexibility, and respond more quickly to customer demands, ultimately improving operational efficiency and competitiveness.
Table of Contents
SMED History
SMED finds its roots in the Toyota Production System (TPS). It was developed by Shigeo Shingo, a renowned Japanese industrial engineer, in the 1950s. At that time, traditional changeover processes in manufacturing were lengthy, often taking hours or even days to complete. Shingo observed that a significant portion of this time was non-value-added, such as waiting for equipment to be adjusted or for materials to be set up. To address this inefficiency, Shingo introduced the concept of SMED. The focus was on reducing changeover and setup times to the shortest possible duration.
SMED Objectives
The primary objectives of SMED revolve around reducing changeover and setup times, improving flexibility, and enhancing overall operational efficiency within manufacturing environments. By achieving these objectives, organizations can streamline their production processes, respond more effectively to changing market demands, and ultimately drive sustainable business growth.
What is Changeover Time?
Changeover time is the total time taken between the last good unit of the previous product (Product A) to the first good unit of the next product (Product B) at full line efficiency.
SMED Approach
The core principles of the SMED approach involve categorizing changeover and setup activities into internal and external elements and focusing on converting internal activities to external ones and streamlining the entire changeover process.
What are Internal Activities?
Internal activities are tasks in the changeover process that can only be performed when the machine is stopped. These activities include tasks such as removing tools, mounting new tools, making adjustments, and setting up the machine. During these internal activities, productivity halts, leading to idle time and lost opportunities for the organization.
What are External Setup Activities?
External setup activities are tasks that can be performed while the machine is still running, thus not interrupting productivity. These include checking change parts for the next product, preparing materials and accessories, arranging tools, reviewing documents, and ensuring prior clearances. Conducting these tasks during machine operation improves efficiency by reducing changeover time and maintaining continuous production flow.
SMED Analysis Process
The SMED analysis process is a systematic approach used to identify and eliminate waste in changeover processes, ultimately reducing changeover time and improving efficiency. Conducting a thorough SMED analysis involves several key steps:
- Understand the Current Process: Begin by comprehensively understanding the existing changeover process, including all internal and external activities involved.
- Identify Internal and External Activities: Distinguish between internal activities (tasks that can only be performed when the machine is stopped) and external activities (tasks that can be completed while the machine is running).
- Convert Internal to External Activities: Aim to convert as many internal activities to external activities as possible. This involves finding ways to perform tasks such as preparation, inspection, and setup while the machine is still running.
- Streamline External Activities: Focus on streamlining external activities to further reduce changeover times. This may involve standardizing procedures, optimizing tooling and equipment, and improving communication between team members.
- Implement Quick Changeover Techniques: Introduce quick changeover techniques such as pre-staging tools and materials, using standardized setups, and employing visual management systems to enhance efficiency.
- Test and Refine: Implement the proposed changes on a trial basis and gather feedback from operators. Refine the process based on observations and feedback to ensure continuous improvement.
- Document and Standardize: Document the revised changeover process and establish standard operating procedures (SOPs) to ensure consistency and sustainability. Train operators on the new procedures to ensure smooth implementation.
Start mapping the changeover process to thoroughly understand the existing practices. This analysis will help identify inefficiencies and areas for improvement. By optimizing each step, we can streamline the changeover process, reducing downtime and enhancing productivity. This initiative will also provide a clearer framework for training new operators on best practices.
What is Changeover Mapping and How to Perform During SMED?
Changeover mapping is a crucial step in the SMED process. This mapping involves detailed observation, recording, and analysis of the changeover process. Below is a step-by-step guide on how to perform changeover mapping during SMED:
- Preparation
- Assemble a Team: Include operators, Line supervisor, maintenance personnel, and Lean experts.
- Gather Tools and Materials: Have video recording equipment, stopwatches, notepads, and any other necessary materials ready.
- Record the Current Changeover Process
- Video Recording: Record the entire changeover process from start to finish to capture all activities.
- Timing: Use stopwatches to measure the duration of each activity.
- Observe and Document Each Activity
- Detailed Observation: Carefully observe each step in the changeover process.
- Document Activities: Note down each activity, its duration, and the sequence in which it occurs. Be specific and detailed.
- Categorize Activities
- Internal Activities: Identify tasks that require the machine to be stopped (e.g., die removal, mounting, adjustments).
- External Activities: Identify tasks that can be done while the machine is running (e.g., preparing tools, checking materials).
- Create a Changeover Map
- Flowchart: Develop a visual representation of the changeover process using a flowchart or diagram. Include each activity, its duration, and whether it is internal or external.
- Gantt Chart: Optionally, create a Gantt chart to show the timing and sequence of activities.
- Analyze the Map for Improvement Opportunities
- Identify Non-Value-Added Activities: Look for activities that do not add value and could be eliminated or improved.
- Highlight Internal Activities: Focus on internal activities that could potentially be converted to external activities.
- Convert Internal to External Activities
- Brainstorming Session: Conduct a brainstorming session with the team to discuss how internal activities can be moved to external activities.
- Implement Changes: Develop and implement strategies to convert these activities (e.g., tool preparation, material checks).
- Streamline External Activities
- Standardize Procedures: Standardize external activities to ensure consistency and efficiency.
- Optimize Tools and Equipment: Ensure that tools and materials are organized and readily available.
- Test and Refine the New Process
- Trial Runs: Conduct trial runs of the new changeover process to test the effectiveness of the improvements.
- Collect Data: Record the time taken for each activity and compare it with the initial mapping to measure improvements.
- Refinement: Make necessary adjustments based on the trial run data.
- Document and Standardize the New Process
- Create SOPs: Develop Standard Operating Procedures for the new changeover process.
- Train Operators: Train all relevant personnel on the new procedures and ensure they understand the changes.
- Periodic Audits: Establish a schedule for regular audits to ensure the new process is followed and continuously improved.
Example of Changeover Mapping
Initial Changeover Mapping (Old Practice)
Activity | Type | Duration (minutes) |
Stop the machine | Internal | 2 |
Remove the old die | Internal | 15 |
Mount the new die | Internal | 20 |
Adjust and set up the new die | Internal | 25 |
Calibrate the machine | Internal | 10 |
Prepare change parts | Internal | 10 |
Prepare materials and accessories | Internal | 10 |
Arrange tools | Internal | 5 |
Review documents and procedures | External | 5 |
Obtain clearances | External | 5 |
Total Changeover Time | 107 minutes |
Optimized Changeover Mapping (After SMED)
Activity | Type | Duration (minutes) | Remarks |
Stop the machine | Internal | 2 | |
Remove the old die | Internal | 5 | Using quick-release clamps |
Mount the new die | Internal | 10 | Using preset alignment tools |
Adjust and set up the new die | Internal | 10 | Using standardized gauges |
Calibrate the machine | Internal | 5 | Using preset calibration settings |
Prepare change parts | External | 10 | Moved to external |
Prepare materials and accessories | External | 10 | Moved to external |
Arrange tools | External | 5 | Moved to external |
Review documents and procedures | External | 5 | |
Obtain clearances | External | 5 | |
Total Changeover Time | 37 minutes |
Example of SMED Implementation in Airlines
Airlines use SMED principles to minimize aircraft turnaround times between flights. This is crucial for maximizing the utilization of aircraft and maintaining a competitive schedule. One major airline successfully applied SMED techniques to streamline its ground operations, achieving significant improvements in efficiency and on-time performance.
Pain areas and challenges
Aircraft turnaround time, the period from when a plane lands until it takes off again, involves numerous activities such as deplaning passengers, cleaning the cabin, restocking supplies, and refueling. Traditionally, many of these tasks were performed sequentially, resulting in longer turnaround times that limited the number of flights an airline could schedule and affected overall punctuality.
To address these inefficiencies, the airline adopted SMED principles to re-evaluate and optimize their ground operations:
- Analyzing Ground Operations:
The airline conducted a thorough analysis of its ground operations to map out all activities involved in the turnaround process. This included deplaning, cleaning, maintenance checks, restocking, and refueling.
- Differentiating Internal and External Activities:
Distinguished between internal activities (tasks that require the aircraft to be stationary) and external activities (tasks that can be done while other processes are ongoing). For example:
- Internal Activities: Tasks such as final maintenance checks and ensuring all passengers have deplaned.
- External Activities: Tasks such as cleaning the cabin, restocking food and beverages, and refueling, which could begin as soon as the aircraft lands or while passengers are still deplaning.
- Streamlining Processes:
The airline focused on converting as many internal activities as possible into external ones. For instance, cleaning crews were trained to begin cleaning sections of the cabin as soon as they became available, rather than waiting for all passengers to deplane. Similarly, refueling could start while other activities were still in progress.
- Standardizing Procedures:
Standardized procedures and checklists were developed to ensure that all ground crew members followed the same streamlined processes, reducing variability and ensuring that each turnaround was handled efficiently.
Results and Benefits
The application of SMED principles led to substantial improvements:
- Reduction in Turnaround Time: Turnaround times were significantly reduced, allowing the airline to schedule more flights with the same number of aircraft.
- Increased Flight Schedules: The reduced turnaround time enabled the airline to increase the number of flights per day, improving overall capacity and revenue.
- Improved On-Time Performance: The efficiency gains helped the airline improve its on-time performance, leading to higher customer satisfaction and better competitive positioning.
Inference:
The successful implementation of SMED in an airline’s ground operations demonstrates the versatility and effectiveness of Lean principles beyond manufacturing. By analyzing and optimizing each step in the turnaround process, the airline was able to achieve faster turnarounds, schedule more flights, and improve overall service quality.
SMED Case Study: Detailed Implementation at ABC Manufacturing
Background of Changeover Process (Old Practice)
At ABC Manufacturing, the changeover process on the metal stamping production line was cumbersome and time-consuming. The old practice involved stopping the machine entirely, which caused significant downtime and reduced productivity.
Old Changeover Activities
- Stop the machine: Production was halted completely.
- Remove the old die: Workers used standard wrenches to remove bolts and screws.
- Mount the new die: New die was manually aligned and mounted.
- Adjust and set up the new die: Die was adjusted using trial and error to achieve proper settings.
- Calibrate the machine: Machine settings were adjusted and verified through multiple tests.
- Check and prepare change parts for the next product: This was done after the machine was stopped.
- Prepare materials and accessories: Also done after stopping the machine.
- Arrange tools: Workers gathered necessary tools after production was halted.
- Review documents and procedures: This was the only external activity, done before stopping the machine.
- Obtain clearances: Done before stopping the machine.
Implementation of SMED (Current Practice)
- Identifying Internal and External Activities
Internal Activities (Machine Stopped)
- Remove the old die
- Mount the new die
- Adjust and set up the new die
- Calibrate the machine
- Check and prepare change parts for the next product
- Prepare materials and accessories
- Arrange tools
External Activities (Machine Running)
- Review documents and procedures
- Obtain clearances
- Converting Internal to External Activities by Applying SMED
- Check and prepare change parts for the next product – Moved to external.
- Prepare materials and accessories – Moved to external.
- Arrange tools – Moved to external.
- Streamlining External Activities
- Standardized Procedures: Developed step-by-step standardized procedures for external activities. For example, preparing change parts was standardized with specific guidelines on when and how to prepare them without waiting for the machine to stop.
- Optimized Tooling and Equipment: Created a dedicated tool cart with all necessary tools pre-arranged. For instance, quick-release clamps replaced standard bolts to speed up die changes.
- Improved Communication: Introduced a visual signalling system (like Andon lights) to alert team members when the machine was about to changeover, ensuring everyone was ready and coordinated.
- Implementing Quick Changeover Techniques
- Quick-Release Clamps: Replaced traditional bolts with quick-release clamps, reducing the time needed to secure dies.
- Standardized Adjustments: Implemented preset gauges and templates to ensure consistent die setup without repeated adjustments.
- Dedicated Changeover Team: Assembled a team specifically trained in quick changeover techniques, including machine operators and maintenance staff.
- Testing and Refining
- Initial Testing: Conducted mock changeovers to identify bottlenecks and inefficiencies. For example, during initial tests, it was discovered that tool arrangement needed further optimization.
- Data Collection: Recorded detailed times for each step of the new process to compare with old times and pinpoint further improvements.
- Continuous Improvement: Adjusted procedures based on data collected. For instance, added additional quick-release clamps based on feedback from operators.
- Documenting and Standardizing
- Develop SOPs: Created comprehensive Standard Operating Procedures detailing each step of the new changeover process.
- Operator Training: Conducted training sessions for all operators, using the new SOPs and hands-on demonstrations.
- Periodic Audits: Established an audit schedule to regularly review the changeover process. Audits included checking adherence to SOPs, tool conditions, and efficiency of the process.
- Documentation: Maintained detailed records of each changeover, including time taken, any issues encountered, and solutions implemented.
- Standardization: Implemented the new changeover process across all relevant production lines, ensuring consistency and efficiency throughout the plant.
Detailed Example: Die Changeover
Old Practice:
- Remove the old die: Took 20 minutes using standard wrenches.
- Mount the new die: Took 25 minutes, required multiple alignment attempts.
- Adjust and set up the new die: Took 30 minutes, involved trial and error.
- Calibrate the machine: Took 15 minutes, repeated several times.
New Practice with SMED:
- Remove the old die: Reduced to 5 minutes using quick-release clamps.
- Mount the new die: Reduced to 10 minutes with preset alignment tools.
- Adjust and set up the new die: Reduced to 10 minutes using standardized gauges.
- Calibrate the machine: Reduced to 5 minutes with preset calibration settings.
Total Time Saved: 60 minutes per changeover.
Gantt Chart: Detailed Die Changeover Old Practice vs. New Practice with SMED
Old Practice Gantt Chart
Total Changeover Time: 125 minutes
Activity | Duration (minutes) | Start Time | End Time |
Stop the machine | 5 | 0 | 5 |
Remove the old die | 20 | 5 | 25 |
Mount the new die | 25 | 25 | 50 |
Adjust and set up the die | 30 | 50 | 80 |
Calibrate the machine | 15 | 80 | 95 |
Check and prepare parts | 10 | 95 | 105 |
Prepare materials | 10 | 105 | 115 |
Arrange tools | 10 | 115 | 125 |
Review documents | 5 | -5 (Before stop) | 0 |
Obtain clearances | 5 | -5 (Before stop) | 0 |
New Practice Gantt Chart with SMED
Total Changeover Time: 32 minutes
Activity | Duration (minutes) | Start Time | End Time |
Stop the machine | 2 | 0 | 2 |
Remove the old die | 5 | 2 | 7 |
Mount the new die | 10 | 7 | 17 |
Adjust and set up the die | 10 | 17 | 27 |
Calibrate the machine | 5 | 27 | 32 |
Check and prepare parts | 10 | -10 (Concurrent) | 0 |
Prepare materials | 10 | -10 (Concurrent) | 0 |
Arrange tools | 5 | -5 (Concurrent) | 0 |
Review documents | 5 | -5 (Concurrent) | 0 |
Obtain clearances | 5 | -5 (Concurrent) | 0 |
By implementing SMED, ABC Manufacturing significantly reduced changeover times, improved efficiency, and minimized downtime, leading to substantial operational improvements and cost savings.
Conclusion: The Power of SMED
Single Minute Exchange of Die (SMED) is more than just a technique; it is a transformative methodology that significantly enhances efficiency, reduces waste, and boosts flexibility across various industries. By optimizing changeover processes, SMED minimizes downtime and labor waste, allowing for quicker product changes and smaller batch sizes. Its principles extend beyond manufacturing to sectors like healthcare and services, driving continuous improvement and empowering employees. The result is sustainable growth through reduced operational costs, higher quality, and increased responsiveness to market demands. Integrating SMED with Lean Six Sigma practices provides a competitive edge, enabling organizations to achieve faster, better, and more adaptable operations.
Harish Kumar Nayak is a dedicated Lean Six Sigma expert with over a decade of hands-on experience in the pharmaceutical industry. Holding a Bachelor’s degree in Business Administration and a Lean Six Sigma Green Belt certification, Harish has honed his skills in process improvement, efficiency enhancement, and quality control.
In his professional journey, Harish has served as an Assistant Manager, leading numerous successful projects. Notably, he has spearheaded initiatives aimed at improving Overall Equipment Effectiveness (OEE), boosting production line throughput and yield, and reducing changeover times for packaging lines. His work has consistently demonstrated his ability to drive significant operational improvements and deliver measurable results.
Beyond his professional achievements, Harish is passionate about making Lean Six Sigma tools and techniques accessible to a broader audience. He enjoys writing articles that break down complex concepts into simple, practical approaches, helping others understand and implement these powerful methodologies in their own work environments.
For insightful articles and practical advice on Lean Six Sigma, visit Harish’s blog at LeanSixSigmaTool.com, where he shares his knowledge and experience to help readers master the art of process improvement.