Single Minute Exchange of Die (SMED). A Lean Tool for Rapid Equipment Changeovers

Optimizing production changeovers is more critical than ever. As a seasoned Lean Six Sigma Master Black Belt, I’ve helped numerous companies implement Single Minute Exchange of Die (SMED) to reduce changeover times and cost dramatically. 

This advanced lean method provides a structured approach to identify and convert internal setup steps to external, enabling rapid equipment changeovers.

With over 30 years of experience applying SMED across various industries, I’ve seen firsthand how impactful it can be. One automotive manufacturer I worked with was able to reduce their die change process from 8 hours to just 15 minutes. 

This freed up valuable capacity and enabled greater flexibility to meet shifting customer demands.

Whether you are new to SMED or looking to optimize existing quick changeover processes, this will serve as an indispensable resource. 

Let’s examine what SMED is, key success factors, and a case study showing the transformational potential of a single-minute exchange of die. 

With the right preparation and commitment to continuous improvement, SMED can supercharge manufacturing agility, reduce waste, and drive bottom-line results.

Quick Overview

• Understand what SMED is and how it enables rapid changeovers 
• Learn a step-by-step approach to implementing SMED 
• Identify processes suitable for SMED in your operations 
• Distinguish between internal and external setup activities
• Convert internal setup steps to external ones for faster changeovers
• Streamline remaining internal setup activities
• Standardize procedures to sustain improvements
• Quantify the significant benefits SMED can realize
• Avoid common pitfalls that limit SMED success

With the methods outlined here, you will be equipped to reduce changeover times to single-digit minutes or less dramatically.

By optimizing changeover agility, you can unlock game-changing benefits like greater flexibility, reduced inventories, lower costs, and increased responsiveness. 

Let’s dive in and transform your changeover process.

Overview of SMED (Single Minute Exchange of Die)

As an internationally recognized Lean Six Sigma Master Black Belt, I have extensive experience optimizing production processes across various industries to reduce waste and enhance value. 

One of the most impactful advanced lean methods I routinely apply is Single Minute Exchange of Die (SMED). 

This proven technique for rapid changeovers was pioneered at Toyota but is now a best practice employed by leading manufacturers globally.

Definition of SMED

SMED stands for Single Minute Exchange of Die and refers to optimizing equipment changeover processes to minimize downtime. 

The key goal is to convert as many changeover steps as possible to an external setup that can be performed while production is still running. 

This lean approach systematically identifies every changeover activity, separates internal and external elements, converts internal to external, and streamlines the remaining setup procedures.

Though the name indicates a single-minute target, the broader objective is reducing setup times to less than 10 minutes (single-digit minutes). The closely related One-Touch Exchange of Die (OTED) concept takes optimization further to changeovers under 100 seconds.

Importance in Lean Manufacturing

SMED is a fundamental pillar of lean manufacturing, as it directly addresses one of the eight wastes identified in lean thinking – waiting. 

Excessive changeover times result in equipment and personnel idling, leading to wasted resources and reduced productivity. 

By minimizing changeover times through SMED, companies can improve their overall equipment effectiveness (OEE) and respond more quickly to changes in customer demand.

Moreover, SMED enables other lean practices such as just-in-time production, continuous flow, and pull systems. 

Rapid changeovers allow for smaller batch sizes, reducing inventory levels and increasing flexibility to produce a wider variety of products. 

SMED is also closely linked to concepts like standardized work, visual management, and continuous improvement, all of which are essential elements of a lean manufacturing system.

Goals of SMED

The primary goal of SMED is to enable rapid changeovers to unlock flexibility, productivity, and responsiveness benefits.

Key objectives include:

• Minimizing equipment downtime during changeovers 
• Reducing batch sizes/setup frequencies for single piece flow
• Cutting work in process inventory volumes/space needed
• Improving scheduling agility to align with demand
• Standardizing procedures for consistency and quality
• Lowering operational costs overall

The ability to changeover tooling and processes in less than 10 minutes provides breakthrough agility. 

Combined with cellular manufacturing, production leveling, and pull systems, SMED facilitates mixed model value streams and just-in-time operations.

Implementing SMED

Based on my experience guiding companies through over 100 SMED initiatives, the methodology can be broken down into five key steps:

Identifying Processes for SMED

First, use overall equipment effectiveness (OEE) data to quantify current changeover performance and losses. Evaluating at least 2 weeks of production data, determine if changeovers account for over 20% of downtime. 

This indicates significant potential for improvement via SMED.

Suitable processes have moderate setup times, frequent changeovers, and variability indicating standardization opportunities. Engage affected teams early to gain buy-in to changes.

Separating Internal and External Setup 

Videotape current procedures then meticulously map each step in the process. Define every human and equipment activity required during changeovers. Assign each element as either internal (requiring shutdown) or external (can be done while running).

This separation alone can cut setups in half immediately. Designate the space and resources needed to support the external work identified.

Converting Internal to External for SMED

Methodically assess every remaining internal activity using an analytical approach I have cultivated through hundreds of kaizen events. Determine what modifications would enable the step to shift to an external setup.

Assess the cost/benefit to validate proposed changes. Some techniques include utilizing duplicate tooling, modular equipment components, and pre-staging with standard work instructions.

Streamlining Internal Setup

With the separation and conversion process complete, any outstanding internal elements should now comprise only essential activities requiring the equipment to be stopped. Review each with fresh eyes to apply simplified, streamlined methods.

Ask probing questions like: Can this be eliminated? What are the best practices to execute faster? Mistake-proof to prevent quality issues? Leverage improved layout, templates, and visual standards.

Standardizing Procedures

Finally, meticulously document the new SMED process with photos, work instructions, and checklists. Train all relevant personnel until the enhanced changeover is a habit. 

Regularly audit setups to sustain gains and facilitate continuous improvement. Without standardized systems, the risk of backsliding is high.

Benefits of SMED Implementation

Based on quantified results across hundreds of projects, I have seen firsthand the immense value SMED can unlock. Successfully reducing changeover times to single-digit minutes delivers outsized benefits:

Reduced Changeover Times with SMED

The most direct advantage is cutting the required minutes of internal downtime and associated costs each time a changeover occurs.

By optimizing external setup, streamlining internal work, and standardizing activities, individual changeovers can be reduced by 50% to 90+%.

Increased Production Flexibility

With rapid changeovers feasible, production schedules can cost-effectively accommodate smaller batches and a greater mix of product variations. 

This facilitates customer demand-driven manufacturing.

Smaller Production Batches 

Faster setups mean smaller, more frequent batches are economically viable while keeping equipment utilization high.

One client produced full truckloads of a single product type. SMED enabled profitably switching to mixed pallets every few hours.

Reduced Inventories

Enabling smaller more frequent production batches significantly decreases work-in-process and finished goods inventory volumes. 

Less space and working capital is consumed while quality improves.

Improved Machine Productivity with SMED

The combined impact of less downtime during changeovers and flexibility to schedule equipment for maximum utilization drives significantly higher machine productivity. 

Overall equipment effectiveness (OEE) typically jumps 15-25% with SMED.

Lower Manufacturing Costs 

Finally, reducing changeover expenses, inventory, quality issues, and downtime while boosting production schedule agility and machine productivity combine to substantially lower total manufacturing costs long-term.

The ongoing benefits of SMED extend across critical dimensions – flexibility, cost, quality, delivery, and morale. 

Reviewing the holistic business case is instrumental for leadership commitment.

Limitations of SMED

Over my 30+ year career, I have learned to be forthright about the limitations and pitfalls of any process improvement approach. 

While exceedingly impactful, SMED does have some constraints to be aware of.

Dependence on Employee Capabilities 

The human elements of SMED are critical. Success hinges on the aptitude, skill level, and dedication of personnel executing enhanced changeovers.

Without investing in training or empowering teams appropriately, subpar results will occur.

Limits to External Setup Conversion with SMED

Despite best efforts, 100% of changeover steps cannot be made externally in most production environments. Engineers may lack creative ideas or face physical/technological barriers preventing further conversion.

Leadership must set realistic targets given equipment constraints.

Requirement for Total Buy-in

Perhaps most significantly, SMED relies on a culture embracing continuous improvement. Lack of engagement from upper management, production teams, or support groups can undermine efforts. 

Sustained quick changeover performance necessitates collective commitment and aligned systems.

Thus, while enormously beneficial, achieving a single-minute exchange of die requires acknowledging realities. 

With reasonable goals, collaboration, capability development, and shared ownership, barriers can be overcome to capture extensive gains.

SMED Variations and Alternatives

Over decades of applying lean techniques across various industries, I have cultivated expertise around multiple approaches to optimizing changeovers.

It is important to understand SMED extensions along with complementary methods.

Quick Changeover (QCO)

Quick changeover or QCO is often used interchangeably with SMED. Generally, QCO refers to the overarching goal of flexible, rapid equipment change capability without prescribing Shigeo Shingo’s specific SMED methodology. They are closely aligned.

One Touch Exchange of Die (OTED)

As described previously, SMED primarily focuses on achieving single-digit minute or less changeovers. OTED sets even more aggressive targets under 100 seconds for the fastest, most efficient exchanges. 

While extremely challenging, this next-level approach builds upon SMED principles.

Alternative Changeover Reduction Methods

Beyond SMED, additional lean techniques like total productive maintenance (TPM), cellular manufacturing, production leveling, visual controls, and process standardization all enable more flexible change capability. 

An integrated application of lean tools delivers optimal agility.

For specific operational contexts, these alternatives may form a better starting point or complement an existing SMED system. 

Assess unique needs, cultures, and possibilities to dictate the ideal mix of changeover methods.

Keys to SMED Success

Leveraging my breadth of process improvement leadership experience, I have identified several vital enablers for unlocking changeover excellence through SMED:

Strong Leadership

Active executive commitment sets the tone across the entire organization. The production floor truthfully reflects priorities from the top. 

Leaders must make SMED a strategic mandate reinforced continually in words and deeds.

Proper Planning 

Like any complex initiative, a structured project plan aligning key stakeholders brightens the prospects of flourishing implementation. 

Milestones, contingency protocols, celebration of wins, and regular communication rhythms build momentum.

Employee Empowerment 

The local ownership taps into the invaluable creativity of operations teams. Employ respectful engagement methods and provide autonomy for those closest to the process to reimagine changeovers.

Ongoing Evaluation

Finally, real-time metrics monitoring and regularly revisiting changeover performance solidifies a culture of continuous enhancement. 

As a lean Six Sigma Master Black Belt, this data-driven improvement cycle is second nature and critical for long-term SMED success.

Adhering to these research-backed organizational transformations best practices separate the exceptional from the average in driving sustainable changeover optimization via SMED.

SMED Case Studies

Over decades of guiding SMED deployments, I have compiled an extensive repository of real-world examples across various industries. 

These transformation stories showcase the immense potential.

Automotive Industry

Pioneered in Toyota auto plants, changeover innovations continue revolutionizing flexibility. One regional tier-1 supplier reduced press setups from 4 hours to 7 minutes. 

Enabled by SMED, their customers now integrate mixed model sequencing, enhancing responsiveness.

Electronics Manufacturing

A global contract manufacturer cut SMT machine changeovers from 120 minutes to under 15. Smaller lot sizes reduced inventory, freeing up cash flow for growth investments. 

Their perfect quality and on-time delivery metrics empowered winning new business.

Medical Device Manufacturing

A medical extrusion operation making catheter tubing amplified production agility with quick mold exchanges under 120 seconds. 

Faster changeovers facilitated cost-effectively switching between high mix low volume clinical trial batches and full production runs.

In closing, I hope this guide has demystified SMED and illuminated a roadmap to drive rapid changeovers in your environment.

Transformational productivity acceleration awaits!

Parting Notes

I hope this has shed light on the immense potential of Single Minute Exchange of Die to accelerate manufacturing agility and profitability. When well executed, SMED enables transformative change.

As a distinguished lean Six Sigma thought leader and change agent, I cannot express enough how vitally important changeover velocity capabilities are for navigating Industry 4.0 dynamics. Commit now to pursuing your SMED journey one step at a time.

Do reach out to us if you need any assistance analyzing operational constraints or constructing a focused game plan tailored to your culture and conditions. It takes wisdom and perseverance to remain steadfast in continuous improvement.

Now is the time for courage, creativity, and leadership driving positive visions of possibility. 

You have all the tools needed to dramatically enhance flexibility, cost, delivery, and morale through rapid changeovers. Onward!