HARDWARE INVESTIGATION
An increasing failure trend for plastic side-release buckles used in waist-worn dog leashes prompted a focused root cause investigation. The intention was to explore ways to enhance the durability of existing products and identify paths for inline improvement.
Year: 2023
Duration: 4 Months
Role: Quality Developer
Scope: Tested and validated plastic hardware solutions for durability and consumer alignment.
To reduce buckle failures through improved component strength or a design update, To ensure product durability while maintaining manufacturability, brand aesthetics, and cost considerations.
OBJECTIVE
Warranty data and feedback from international stakeholders highlighted an increasing trend of inoperable power buttons. Due to process constraints, we believe the case total was underreported. While the recorded failure rate and ratios were within acceptable quality limits, the issue trend was significantly up year over year. Affected and non-affected pieces were cosmetically identical.
WHY
Due to in-house test limitations and the intended hardware use case, the test setup required webbing threading through the buckle to most accurately measure tensile strength. The setup involved a mechanical lever system to apply force and a grounded jig assembly to ensure stable and reliable results. Each sample underwent a straight-line pull to catastrophic failure. 20 pieces of each buckle were tested to accurately assess performance and ensure repeatable results. The test was designed to isolate the components' relative strengths while mimicking the real-world use case of the buckle in a common leash orientation.
TESTING
Two alternative suppliers were evaluated to identify potential solutions. Tensile tests were conducted to compare the strength, failure thresholds, and overall suitability of the buckles. Four sample buckle styles were tested. The current inline buckle was used as a baseline from Supplier A. One buckle from Supplier B and two buckles from Supplier C were tested against this baseline. These tests measured: Average tensile strength, lowest expected tensile load (LETL) and break point variance.
EXPLORATION
supplier a
Limited utilization across the brand, primarily focused on a single buckle component. Observed higher-than-acceptable failure rates in real-world use, leading to potential reliability concerns.
Baseline - Nylon Blend
supplier B
Offered one high-strength buckle at a significant cost increase. Limited color options, requiring high MOQs for custom colors.
REINFORCED NYLON
supplier C
POM & INDUSTRIAL
Offered one high-strength buckle at a significant cost increase. Limited color options, requiring high MOQs for custom colors.
No viable market solution was identified. No inline improvements were approved.
OUTCOME
None of the tested samples met the pre-defined project strength threshold. The Baseline buckle, despite a failure rate, failure ratio, and RPN value exceeding the brand's acceptable quality limits, provided the best combination of price, strength, and color options. Despite failing to implement a new solution, the investigation yielded valuable data that will inform future leash designs, including key insights into materials, costs, and manufacturing constraints.
Alternative hardware/materials were not considered due to the brand's historic challenges with metal hardware in waist-worn configurations. While tooling modifications and other solutions to strengthen the existing buckle were explored with suppliers, the associated costs proved prohibitively high for the current business case.