The strength of upper stitching is a key parameter in assessing the overall quality of footwear. This test not only affects the product’s structural integrity and durability, but also plays a crucial role in maintaining its shape and aesthetic appeal over time. A well-executed stitch is a hallmark of reliability, preventing deformation, seam failure, and premature damage during use.
Test Description
The seam strength test is designed to measure the mechanical performance of the joints within the upper. To do this, a sample containing a seam is subjected to increasing tensile force using a dynamometer until it breaks. The main parameters measured include:
- The force required to break the seam (tensile strength);
- The type of failure (e.g., thread breakage, material tear, or separation between stitched components).
Sample Preparation
Samples are prepared according to a standardized protocol to ensure reliable and repeatable results. The key stages include:
- Sample cutting: selecting a portion of the upper that contains a representative seam from the production line;
- Conditioning: stabilizing the sample in a controlled environment to ensure consistent temperature and humidity conditions;
- Structural simulation: when necessary, preparing samples that accurately replicate the structure of the assembled upper.
Equipment
The test is conducted using a dynamometer, an instrument capable of applying a controlled, progressive force to assess the material’s behavior up to the point of failure.
Reference Values and Standards
- Minimum required value: 10 N/mm
- Applicable standard: ISO 17697 – Method B
Benefits for the Footwear Industry
- Improved product quality and durability;
- Enhanced comfort and safety for the end user;
- Optimized manufacturing processes through early identification of suitable materials;
- Compliance with international standards, facilitating access to regulated markets.
Our laboratory specializes in advanced seam strength testing, carried out in accordance with the latest international standards.
Contact us today for expert consultation and discover how to enhance your footwear’s performance, starting from the details that make the difference.
