SMED Example: From Theory to Successful Practice in Lean Manufacturing

The journey from a cluttered workshop to a streamlined production floor often begins with a single, pivotal step: implementing SMED. This lean manufacturing technique, focused on reducing equipment changeover times, bridges the gap between theoretical efficiency and practical application.

Read on and explore a real-world SMED example that illustrates how theory translates into tangible improvements in manufacturing agility and productivity.

SMED Basics

Before delving deeper into this pivotal efficiency-enhancing tool, it’s crucial to grasp the meaning behind the acronym SMED. Starting from the end, the “D” in SMED represents “dies” or a singular “die.” In manufacturing, a die is an essential tool that shapes and sizes the product, functioning akin to a stamp or an industrial version of a cookie-cutter.

Advancing to the “E,” it signifies the “exchange of dies.” Given that each die is tailored for producing specific product dimensions and shapes, different products necessitate different dies. Consequently, exchanging dies refers to the process of transitioning the production line from fabricating one product variant to another.

The initial letters, “SM,” denote “single-minute,” encapsulating the ideal timeframe for this transition — aiming for the exchange of dies to occur within a single minute. However, this concept can be expanded to signify a “single-digit minute exchange of dies,” implying the goal is to complete the die exchange in under ten minutes, thereby streamlining production processes and enhancing operational efficiency.

Related: SMED in Lean Manufacturing: What It is And How You Can Benefit From It

SMED Example

To fully grasp the potential of SMED, it’s beneficial to examine a practical example of its implementation. This segment outlines a straightforward and actionable guide for applying SMED principles effectively.

Before You Start

Preparation Phase

SMED has the capacity to revolutionize changeover processes for nearly all manufacturing entities engaged in changeovers. However, it’s essential to recognize that diving into SMED shouldn’t necessarily be the initial action step. Given the limited resources most companies face, prioritizing efforts where they can yield the most substantial returns is critical.

Identify Priorities

What should take precedence then? The cornerstone for most organizations should be to establish a robust understanding of where losses in productive time are occurring. This involves making informed decisions regarding improvement projects, grounded in solid, empirical data. To achieve this, instituting a mechanism for the diligent collection and analysis of manufacturing performance metrics is imperative.

A universally acknowledged benchmark for evaluating manufacturing efficiency is the measurement of OEE (Overall Equipment Effectiveness). This includes a further segmentation of OEE loss categories into the Six Big Losses, with an in-depth examination of OEE Availability losses segmented by Downtime Reason Codes. These codes are instrumental in tracking the duration of changeovers among other factors.

It’s advisable to gather manufacturing performance data over a minimum span of two weeks. This duration is essential to acquire a comprehensive understanding of where losses in productivity predominantly lie.

Decide on a Course of Action

• SMED: Should the analysis reveal that changeovers account for a considerable portion of productivity loss (for instance, 20% or more), embarking on a SMED initiative would be a wise course of action.
• TPM: On the other hand, if changeovers do not constitute a major source of productivity loss, it may be more prudent to initially focus on implementing a TPM (Total Productive Maintenance) strategy.

First Step: Identify Pilot Area

The foundational step in adopting the Single-Minute Exchange of Die (SMED) methodology involves pinpointing the most suitable pilot area for its implementation. This decision is critical as it sets the stage for the entire process, influencing the effectiveness and success of the SMED program. Here’s a structured approach to identifying this pivotal pilot area, focusing on specific criteria that ensure a balanced and impactful selection:

Criteria for Choosing the Pilot Area

1. Changeover Duration: Opt for equipment where the changeover time is substantial enough to offer significant improvement opportunities but is manageable in scope. For instance, equipment with a one-hour changeover time strikes a good balance.
2. Variability in Changeover Times: Look for scenarios where there’s noticeable inconsistency in changeover durations, such as times fluctuating between one to three hours. This variability indicates potential for standardization and improvement.
3. Frequency of Opportunities: The chosen equipment should undergo changeovers frequently enough to allow for rapid testing and refinement of proposed enhancements. Multiple weekly changeovers are ideal.
4. Team Familiarity and Engagement: It’s essential that the personnel who interact with the equipment regularly—operators, maintenance staff, quality assurance professionals, and supervisors—are knowledgeable and motivated about the SMED project. Their insight and enthusiasm can drive meaningful changes.
5. Operational Impact: Ideally, select equipment that acts as a bottleneck within the production process, as improvements here will yield immediate and noticeable benefits. To mitigate risks associated with potential downtime during the project, consider strategies like building up temporary inventory reserves.

Building Consensus and Establishing a Baseline

Involving a diverse group of employees in selecting the pilot area is key to securing support for the SMED initiative and ensuring a variety of perspectives contribute to the project. After choosing the target equipment through consensus, it’s essential to measure the current changeover time as a baseline. This measurement tracks the time from the last high-quality production at full speed to the start of the next, mindful of the “Hawthorne Effect” which suggests performance may temporarily improve under observation. Using pre-existing data when possible helps achieve a more accurate baseline, setting the stage for impactful improvements.

Second Step: Identify Elements

In this phase, the team collaboratively identifies every component involved in the changeover process. A highly effective method for achieving this is by recording the entire changeover process on video. 

This allows the team to review the footage and compile a comprehensive list of components, detailing:

• Description: The specific tasks performed.
• Time Requirement: The duration each component takes to complete.

Practical Advice for Effective Identification:

• Component Quantity: Typically, documenting a changeover will yield between 30 to 50 distinct components.
• Utilizing Sticky Notes: An efficient way to note down and organize components is by using sticky notes on a wall, arranged according to their sequence in the changeover process.
• Differentiating Between Human and Machine Actions: It’s crucial to distinguish between actions performed by operators (“human” elements) and those carried out by the equipment (“equipment” elements), as human elements often present more straightforward optimization opportunities.
• Engaging Multiple Observers: While filming the changeover, having several team members observe and take notes can be invaluable. Observers may catch details that the video does not capture.
• Observation Focus: The goal should be to observe without intervening, allowing the changeover to proceed as it typically would.

Third Step: Separate External Elements

This phase focuses on pinpointing activities within the changeover process that can be executed without disrupting ongoing operations, thus being classified as “external” activities (i.e., they can occur before or after the equipment is active).

The team should evaluate each activity with the question: 

• Is it possible for this task, in its current form or with slight modifications, to be carried out while the equipment is operational?

Should the answer be affirmative, the activity is designated as external and reassigned to either precede or follow the main changeover period.

Potential tasks suitable for this adjustment include:

• Retrieval: Gathering necessary parts, tools, materials, and instructions.
• Inspection: Conducting checks on parts, tools, and materials.
• Cleaning: Undertaking cleaning operations that don’t interfere with ongoing processes.
• Quality Control: Performing quality assessments on products from the previous batch.

The result of this stage should be a refined list of changeover activities, organized into three categories: External Activities (Before Changeover), Core Activities (During Changeover), and External Activities (After Changeover).

Fourth Step: Convert Internal Elements to External

This phase entails a thorough review of the current changeover activities, aiming to reclassify as many internal activities (those that occur during downtime) as possible to external ones (those that can be done while operations continue).

The team should contemplate each internal activity with the mindset: 

• If it’s feasible to transition this activity to an external one, what would be the approach?
• What steps would we need to take?

Such deliberation will generate a roster of activities ripe for reclassification. These should then be ranked based on potential impact, focusing initially on those with the most favorable cost-benefit ratio. This involves assessing:

• Cost: The resources and labor required for adaptation.
• Benefit: The potential reduction in changeover time.

With priorities set, efforts can shift towards implementing these modifications

Techniques for transitioning internal to external activities include:

• Advance Preparation: For example, pre-heating components before they’re needed in the changeover.
• Utilization of Duplicate Tools: Such as using spare jigs to make adjustments beforehand.
• Equipment Modularization: For instance, swapping out a printer rather than recalibrating the existing one, allowing preparation for the next job in advance.
• Equipment Modification: Like adding safety features that permit certain maintenance tasks to proceed without halting operations.

The outcome of this step should be an evolved list of changeover activities, characterized by a reduced count of internal activities and an expanded suite of external ones, thereby streamlining the overall process.

Step Five: Streamline Remaining Elements

At this stage, the focus shifts to the refinement and optimization of the remaining changeover activities. The objective is to make these processes more efficient, aiming for completion in the shortest possible time. Priority is placed on internal activities, as refining these directly contributes to the overarching goal of reducing changeover durations.

For each activity, the team examines two key questions: 

• Can we reduce the time it takes to complete this task? 
• Is there a way to simplify the process?

A straightforward cost/benefit analysis continues to guide the prioritization of improvements, similar to the approach in previous steps.

Methods for enhancing efficiency include:

• Quick Release Systems: Implementing solutions like quick-release mechanisms to avoid time-consuming bolt removals.
• Adjustment Reduction: Employing strategies such as preset numerical standards, fixed settings over adjustments, visual alignment aids, or using shims for uniform sizing.
• Motion Optimization: Reconfiguring workspaces to minimize unnecessary movement.
• Reducing Downtime: Prioritizing immediate quality inspections to cut down on waiting periods.
• Standardization of Tools: Streamlining tool variety to expedite tasks.
• Parallel Processing: Allocating multiple workers to simultaneous tasks, while closely monitoring for safety.
• Automation: Considering mechanization as a final option due to its complexity and investment requirements.

The result of this step is a comprehensive set of streamlined work instructions, leading to a significantly improved changeover process.

What You Should Do Next

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