Shigeo Shingo, an internationally acclaimed industrial engineer and expert on the Toyota Production System, devised SMED. His efforts reduced changeover time for transfer stamping machines from hours to 180 seconds, saving both time and resources for production lines alike.
What is SMED?
SMED is an innovative process that significantly shortens changeover times between production runs. This is achieved by categorizing changeover elements as internal or external to machine operation time and then adapting or simplifying them during normal machine operations - thus significantly decreasing changeover times, often down to mere minutes!
An SMED project can lead to substantial savings for any company. For instance, an action figure manufacturer selling them at $20 each could lose one sale every 60 seconds as they switch from mold to mold; with proper planning and execution, an SMED project may reduce this to 10 or fewer seconds!
An SMED pit crew can serve as an analogy for SMED, with process setups and changes representative of pit stops. Pit crews employ various strategies to streamline their work - prepositioning all tools before beginning an actual pit stop, using standard attachment points and methods, etc. Their aim should be to reduce tire swap times from 15 minutes to sub-10 seconds as quickly as possible.
SMED projects at manufacturing plants may involve switching products, moving between dies, modifying jigs, gauges, materials, and more to modify processes or modify equipment while it runs or shuts down; some steps may even need to be completed when the machine shuts down - SMED projects look at ways of streamlining or eliminating these steps to reduce changeover times from hours or days down to minutes (or single digits).
Once a baseline for your changeover process has been established, elements that can be completed while the machine runs are prioritized. Internal setup processes that remain are examined for opportunities for optimization and simplification, such as eliminating motion, waiting, adjustments, creating parallel operations, or standardizing hardware.
SMED can significantly decrease manufacturing costs by streamlining processes and reducing changeover times, improving OEE, increasing machine startup rates, and helping smaller lot sizes meet customer demand faster while reducing WIP and inventory levels.
What are the benefits of SMED?
SMED (short for "Simple Manufacturing Equipment Changeover") is an equipment changeover process developed in the 1950s by industrial engineer Shigeo Shingo to assist manufacturing companies in reducing inventory levels and boosting production efficiency. Lean practitioners use SMED in virtually every setting, from factories and fast food restaurants to offices.
SMED (Source for Manufacturing Excellence and Delivery) aims to eliminate non-value-adding procedures and streamline those remaining so teams can focus on only those critical steps needed for production efficiency and reduce waste while improving employee morale.
Initial die exchange processes were called Quick Die Change; however, Shingo later changed it to Single Minute Exchange of Die to reflect his goal of shortening setup times as much as possible. Unfortunately, "single minute" can be misleading since changeover procedures do not need to take only a minute; single-digit minutes (less than 10) would be more suitable.
SMED can save time, but its other advantages also include:
Reduced manufacturing costs. Shorter changeover times lead to reduced downtime periods and lower material, labor, and energy costs. Increased flexibility. Shorter changeover times give manufacturers more ability to produce just enough products at any time while decreasing inventory carrying costs and carrying costs.
Increased Quality. Rapid changeover times allow for quicker product switches with increased frequency, meaning higher levels of consistency in quality.
Implementing the SMED process can be difficult and complex, impacting every aspect of business operations. Training your team on new procedures to explain why they will increase efficiency is crucial to ensuring the transition runs smoothly; also, developing standard work instructions helps ensure everyone knows exactly what needs to be completed and when.
Last but not least is to reduce unnecessary motion by organizing storage. Hence, it is easier for team members to find what they need quickly, using point-of-use storage where appropriate and clearly labeling equipment settings. This will also help mitigate human error during context-switching processes.
How can SMED be implemented?
Once your team is prepared to implement SMED, they must become organized. Create a list of all the elements involved in changeover processes and prioritize which can be completed while running while others must wait offline; this can speed up transitioning to single-digit minute setup times as quickly as possible. Also, consider whether any elements can be done simultaneously, such as tool prep while another part is produced; similar to how NASCAR pit crews operate, this can streamline processes further while using easily accessible standard tools can simplify processes further.
Once you have documented all of the internal elements, the next step should be identifying waste - both motion-related and time-based. To do this, simplify procedures, remove steps, and eliminate interactions that are no longer needed; equipment modification may also be required; designing highly portable machines reduces interface requirements while modular components enable moving them quickly between production lines.
Finally, it's essential to establish an initial changeover time baseline. This will enable a comparison of SMED implementation results against those from other companies that have already adopted the method. It should also recognize any Hawthorne Effect that might help your changeover times improve simply through watching and learning from the process itself.
SMED can be applied effectively in factories that manufacture action figures for children, which sell for about $20 each. The manufacturer can produce one every 60 seconds, so each time they switch molds, they lose out on sales worth $20.
To reduce these costs, the company started employing SMED strategies, such as switching from manual mold changes to one-touch systems for mold changes and cutting preparation time down from hours to minutes; lean manufacturing practices allowed them to achieve just-in-time production goals and cut inventory levels significantly.
What are the challenges of SMED?
SMED strives to reduce the time needed to change equipment from one product to another by identifying and eliminating unnecessary steps from its process and changing internal setup elements into external ones.
Industrial engineers have long understood the need to shorten changeover times. Shigeo Shingo, an engineer who worked at Toyota, developed the SMED system in the 1970s; quickly becoming popular, its usage has resulted in documented reductions of changeover time averaging 94%.
SMED can be invaluable for shortening changeover times, but companies must remember that it will only solve some of their production woes. To maximize its use and reap maximum returns from SMED, companies should focus on optimizing human and machine processes as part of a comprehensive approach to improvement.
Human improvements can be accomplished through organization and preparation, while machine improvements may involve engineering or optimization. Examples of human improvements would be creating standard work instructions, placing tools near the changeover area for easy access, labeling equipment settings, and eliminating wasteful motion.
Once a company has identified areas to improve, it must devise a plan for implementing SMED. This may involve assigning a project leader, holding brainstorming sessions, and training employees on how the new process works. Furthermore, they should set a timeline for reaching their desired results.
An unfortunate hazard of SMED processes is their tendency to prioritize speed over quality, leading to rushed or incomplete changeovers that compromise productivity and increase the risk of defects. Furthermore, it should be remembered that any successful implementation will still involve some downtime - even if only for minutes at a time.
Implementing SMED requires considering that learning its processes may take some time for teams, mainly if changes to production are significant. To combat this, new employees should receive training on SMED before beginning production work; this will give them a deeper understanding of its workings and facilitate more straightforward adaptation.
Pros of Single Minute Exchange of Die (SMED)
- Reduced Changeover Time: The primary benefit of SMED is the drastic reduction in the time required for changeovers.
- Increased Productivity: With quicker changeovers, more time is available for actual production, increasing overall productivity.
- Cost Savings: Reduced downtime leads to lower operational costs and increased profitability.
- Flexibility: Faster changeovers allow for greater flexibility in production schedules and the ability to respond to market demands.
- Improved Quality: A well-executed SMED program can also lead to improvements in product quality.
- Lean Manufacturing: SMED is a critical component of lean manufacturing, contributing to waste reduction and efficiency.
- Better Utilization of Resources: Faster changeovers mean better utilization of machines and manpower.
- Competitive Advantage: Companies that successfully implement SMED often gain a competitive edge regarding speed and responsiveness.
- More straightforward Scheduling: Reduced changeover times make production scheduling more accessible and flexible.
- Employee Engagement: Implementing SMED often involves teamwork and problem-solving, which can boost employee engagement.
Cons of Single Minute Exchange of Die (SMED)
- Initial Costs: Implementing SMED may require investment in new tools or equipment.
- Training Requirements: Employees need to be trained in the SMED methodology, which can be time-consuming.
- Complexity: While the concept is simple, the implementation can be complex and require detailed analysis.
- Resistance to Change: As with any new process, there may be resistance from employees accustomed to the old ways of doing things.
- Limited Applicability: SMED is most effective when frequent changeovers are required; it may be less beneficial in other scenarios.
- Risk of Rushing: The focus on speed could lead to mistakes or oversights.
- Dependency on Skilled Workers: The effectiveness of SMED often depends on the skill and cooperation of the workforce.
- Short-term Disruptions: Initial implementation may cause disruptions in the regular workflow.
- High Expectations: Promising dramatic improvements can lead to high expectations, and failure to meet them can be demoralizing.
- Ongoing Maintenance: SMED is not a one-time activity; it requires constant effort to maintain and improve the process.
