DFS : Design for Serviceability

Introduction

Design for Serviceability (DFS) is part of a broader concept called the Design for Excellence (DFX). DFX aims to enhance product performance across various criteria, such as manufacturability, reliability, serviceability, and sustainability.

DFS specifically focuses on designing products to be easily serviced, repaired, and maintained throughout their lifecycle. By integrating serviceability considerations early in the design process, companies can reduce downtime, extend product life, and improve customer satisfaction.

What is serviceability?

B.S. Dhillon provided the following definition: "Serviceability. This is the degree of difficulty or ease with which a product can be restored to its operable state"[1].

SAE defined serviceability as "a measure of the ease with which routine or periodic, as well as nonscheduled maintenance or repair actions, can be performed on a machine"[2].

Linkage to other DFX methods

DFS is closely related to other DFX methods, such as Design for Manufacturability (DFM), Design for Reliability (DFR), and DFE (Design for Environment). Each of these methodologies emphasizes a specific aspect of product development but often overlaps with serviceability concerns:

• Design for Assembly ensures products are easy to build. It focuses on reducing parts, standardizing fasteners, and other factors that impact serviceability.
• Design for Reliability focuses on product durability and longevity, reducing the frequency of service interventions.
• Design for Environment promotes environmentally friendly design, including easy disassembly. It overlaps with serviceability aspects.

DFS Guidelines

Implementing DFS involves several best practices and guidelines, including the following aspects:

• Establish service goals: Define which service procedures are more crucial than others. Apply high priority for service/maintenance solutions for potential frequent failures or severe effects of a failure mode. Use the FMEA method to understand product failure modes, effects, and the likelihood of failure causes. Dewhurst and Abbatiello[3] recommend FMEA before establishing the service goals.
• Modular Design: Creating modular components allows for easy replacement and repair of individual parts without affecting the entire system.
• Standardization: Standard parts and fasteners facilitate quicker repairs and reduce the need for specialized tools. This concept strongly overlaps with DFM and DFA.
• Access to parts: Designing products to allow standard tools to access assembly points, fasteners, etc. Special tooling and extensive disassembly is, therefore, limited.
• Service manuals: Provide detailed service documentation to guide maintenance personnel. This speeds up their learning curve.
• Diagnostic Tools: Integrating diagnostic tools and software that help identify issues quickly. It simplifies and speeds up the repair process. For example, implement "service mode" in the product's software to allow the maintenance personnel to verify product subsystems quickly. It reduces the troubleshooting time and streamlines the overall service effort.

DFS Pros

Implementing DFS offers numerous advantages, including:

• Reduced Downtime: Easier and quicker repairs mean less downtime, which is critical for industries relying on continuous operation.
• Cost Reduction: Lower maintenance and repair costs due to reduced labor and parts expenses.
• Extended Product Life: Products designed for easy serviceability tend to have longer lifespans, providing a better return on investment.
• Enhanced Customer Satisfaction: Customers appreciate products that are easy to maintain and repair, leading to better brand loyalty.
• Environmental Benefits: Easier disassembly and repair contribute to sustainability by reducing waste and promoting recycling.

DFS Cons

Despite its benefits, DFS also presents some challenges:

• Higher Initial Costs: Designing for serviceability can increase initial design and manufacturing costs due to additional considerations and features.
• Complexity: Balancing serviceability with other design requirements can be complex and time-consuming.
• Potential for Overdesign: There is a risk of overdesigning components, making them more complex than necessary, which can counteract the benefits.

Standards and Guidelines

Following are some examples of standards and industry guidelines that support DFS implementation:

• DOD-HDBK-791. 1988. Military Handbook: Maintainability Design Techniques. Washington: U.S. Department of Defense.
• IEC 60300. Dependability management, including reliability, availability, and maintainability. Provides guidelines for maintainability, which overlaps significantly with serviceability.
• SAE JA1011. Evaluation criteria for reliability-centered maintenance (RCM). It includes serviceability aspects.

Summary

Design for Serviceability (DFS) is a vital component of the broader DFX methodology, emphasizing the importance of designing products that are easy to maintain and repair. By considering serviceability from the early stages of design, companies can achieve significant benefits, including reduced downtime, cost savings, extended product life, and enhanced customer satisfaction. However, implementing DFS requires careful balancing with other design priorities and can involve higher initial costs and complexity. Incorporating the serviceability concept into the early phase of the product design ultimately contributes to a more sustainable and efficient product lifecycle.