Design for Longevity

In the realm of high-performance engineering products, durability is often a prized attribute. Whether it's a rugged vehicle, a precision medical device, or a heavy-duty industrial machine, longevity is synonymous with quality and reliability, and an expected attribute for products that become high-value assets for people or companies. However, as we strive to create products that last longer, we encounter a paradox: how can we extend product lifespans without compromising innovation, economic growth, or the environment?

The Three Dimensions of Durability

To address this challenge, it's essential to consider the three dimensions of durability:

1. Technical Durability: This refers to a product's physical and mechanical properties that allow it to resist wear and tear. Factors such as material choice, manufacturing processes, and robust design contribute to technical durability. However, excessive over-engineering can lead to inefficiencies.
2. Functional Durability: This aspect focuses on the product's ability to perform its intended function over time, including the product's ability to remain relevant and efficient over time, despite advancements in technology or industry standards. Factors such as maintainability, repairability, and upgradability contribute to functional durability.
3. Social Durability: This dimension relates to the emotional, social and cultural factors that influence a product's lifespan. Consumer preferences, fashion trends, changing lifestyles, and regulatory requirements can impact the perceived value and usefulness of a product.

The Pros and Cons of Making Durable Products Last Longer

Pros:

1. Environmental Benefits: Extending the lifecycle of products reduces the environmental impact associated with sourcing, manufacturing, transportation and retailing of a new product, plus those related to end-of-life disposal, mainly if the product does not have any re-processing pathway after it. This aligns with sustainability goals and regulatory standards like the EU’s Ecodesing for Sustainable Products Regulation (ESPR).
2. Cost Savings and Satisfaction for Customers: End-users benefit from reduced capital expenditures, particularly in industries where product replacement is costly and disruptive (e.g., imaging medtech). A product with a long lifespan might be perceived as more expensive, but if the cost is divided by the amounts of years in service, it could be reduced considerably and long-term value increases (with the proper business model to support it.)
3. Enhanced Brand Reputation: Offering durable products demonstrates a commitment to sustainability, attracting eco-conscious customers and strengthening brand loyalty. Besides, a reputation for producing high-quality, long-lasting products can boost brand loyalty.

Cons:

1. Increased Design Complexity: Extending durability can require additional engineering efforts to address wear and tear over longer periods without overdesigning. Old Failure Modes and Effects Analysis (FMEA) must be revisited, to ensure that all potential failures in larger periods have been addressed, and new testing procedures might be required to validate the extended lifespan.
2. Increased Upfront Manufacturing Costs. As the control of processes requires to be stricter, traditional quality management systems might not be enough. Implementing robust quality control measures, such as additional inspections and testing, can increase labour costs and overhead expenses. However, this can lead to significant savings in the long run by preventing defects and recalls and, thus, warranty costs.
3. Potential Material Intensity: Achieving greater robustness could demand more materials, potentially increasing weight, cost, carbon footprint and higher risks related to conflict or critical materials—counterproductive to sustainability goals.
4. Revenue Implications: Fewer replacements mean fewer sales, which can hurt traditional business models reliant on repeat purchases.

Strategies to Achieve Longevity

1. Life cycle and circular thinking: Use Life Cycle Assessment (LCA) as a design tool and make a Circular Pathways Map to identify opportunities for components or materials reprocessing in the early concept design of your product.
2. Understand the full and extended lifespan. You will need to understand the implications of the use and misuse scenarios and how the different loads (mechanical, thermal, vibration, etc) and fatigue of every single component influence the durability of a system or the full product. Ensure that you revisit your FMEA at component, system and product level and you set targets based on realistic (and data-based) expectations.
3. Target the weakest components: Identify which are the components or consumables that will affect your full product's durability, and work on them to make them robuster, or modularize them for easy accessibility and maintenance, repair or replacements. You will need to test products under various conditions to identify potential weaknesses.
4. Smart Material Selection: Use advanced materials that offer a high strength-to-weight ratio, such as composites or lightweight alloys.
5. Modularity and Reparability: Design components to be modular, ensuring they are easy to replace, repair, or upgrade. Enable key components and consumables to be swapped or upgraded to keep up with technological advancements. Use standardized modules or components to maximize compatibility and ease of maintenance. Additionally, your platform should not only last the longest but also retain the highest residual value. Create platforms that accommodate future technologies and expanded functionality while featuring a timeless design that can seamlessly integrate into future products.
6. Topological Optimization and Additive Manufacturing: This tailored process optimizes performance by minimizing material usage, reducing stress from joining mechanisms, and mitigating manufacturing wear and tear. It enables the creation of complex geometries and the repair of components, extending their lifespan and reducing waste.
7. Predictive Maintenance and IoT: Embed sensors, IoT capabilities or other mechanisms to monitor product performance and preemptively address wear issues before failures occur. Define disassembly and reassembly requirements.
8. Functional Longevity Over Structural Longevity: Focus on maintaining performance through maintenance and upgrades rather than building excessive structural durability.
9. Monitor performance in the field: Gather data on product performance in real-world conditions as a predictive tool and keep the R&D teams informed for future design decisions.
10. Engage and collaborate. Collaboration with industrial hubs, both from your own industry and another one, plus engagement with suppliers, reprocessors and customers, will provide you with more tools to understand and extend the longevity of your product.

Business Models for Revenue in a Longevity-Focused Market

1. Products as Services (PaaS): Shift from selling products to offering services. Sell the function, not the product.
2. Subscription Models: Offer subscriptions for maintenance, upgrades, consumables replacements or additional features.
3. Refurbishment and Remanufacturing: Develop programs to recover and refurbish or remanufacture products for resale, capturing value from older units.
4. Leasing Models: Lease products to customers, taking responsibility for maintenance and end-of-life recycling.

End thoughts

Designing for longevity requires a nuanced approach, balancing durability with sustainability and profitability. By adopting system approaches that consider the design and the business model, companies can extend product life while staying competitive. This strategy not only supports environmental goals but also strengthens customer trust and positions businesses as leaders in sustainability.

Excited to expand the conversation?

Let's connect! There are many ways to extend a product's lifespan, depending on the function (and market) of your product. We can work together to find the best solution for you.

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