SES N 3247 Textile Seam Strength and Fatigue Tests

Developed by Suzuki Motor Corporation as part of its interior materials/textile standards, the “SES N 3247 Textile seam strength and fatigue tests” standard is one of Suzuki's key quality standards for automotive interior trim and upholstery materials. This standard specifically evaluates the seam performance of seat upholstery (fabric, leather, artificial leather, etc.).

In the automotive industry, textile seam strength and fatigue refers to how well stitched joints in textile components such as seat covers, upholstery, and airbags withstand forces and prolonged use.

Seam strength is the maximum force a sewn seam can withstand before breaking. In other words, it's an expression of how strong the seam is when pulled. In the automotive industry, seat upholstery seams must withstand passenger weight and tensile and compressive forces. Also, door panel seams should not come undone under tension. These forces can cause thread breakage, fabric tearing, and seam unraveling (slippage). For example, if a car seat seam comes undone when someone sits on it, this indicates low seam strength.

Textile seam fatigue refers to how a seam behaves under repeated loading over time. In other words, it's an expression of how long the seam lasts after thousands of uses. In the automotive industry, repeated sitting and standing, constant vibrations during driving, and temperature changes are examples of such forces. Over time, threads can loosen, seam holes can enlarge, and the seam can gradually come undone. For example, if a seat seam looks good at first but comes undone after a year, it indicates poor fatigue performance of the seam.

Briefly,

• Seam strength: Indicates instantaneous resistance; the load type is static (single-use load).
• Stitch fatigue: Refers to long-term durability, where the load type is dynamic (repeated cycles).

The SES N 3247 standard defines the following two basic test methods:

• Seam strength test: Measures how much force a stitched textile structure can withstand before breaking. In principle, a sample is placed in a tensile testing machine. Force is applied perpendicular or parallel to the seam. The sample is pulled until it breaks. The maximum force is recorded. This value is reported as seam strength.

This test determines the following:

• Suture rupture
• Fabric tearing
• Opening stitches

It is important in the automotive industry in the following areas:

• Seat covers
• Door interior trim
• Steering wheel covers

The aim is to prevent the seams from coming undone during use, as seams are the weakest point in the textile structure.

• Seam fatigue test: Measures how seams deteriorate over time under repeated loads. In principle, a sample is fixed in place. Repeated loads or impacts are applied to it. A specific number of cycles (e.g., thousands of impacts) are performed. Finally, the damage is checked.

This test determines the following:

• Suture rupture
• Hole enlargement
• Thread loosening is examined.

Typical test specifications are as follows:

• cyclic load
• A combination of impact and pressure.
• Thousands of repetitions (for example, 7000 cycles)

It is important in the automotive industry in the following areas:

The SES N 3247 standard is crucial for ensuring that seams used in automotive textiles are safe, durable, and long-lasting. The main reasons why this standard is considered important are as follows:

• Importance from a safety perspective: Seams are the weakest point of seats and interior trim parts.
• Weak stitching can cause the seat cover to come undone.
• In seats equipped with side airbags, stitching performance can be vital.
• The stitching should not break under sudden loads (accident, hard sitting).

This standard prevents seams from becoming a safety hazard.

• It ensures longevity and durability: Vehicles are used for years, and the seams are constantly stressed for the following reasons:
• Sitting/standing (thousands of repetitions)
• Friction and tension
• Temperature and humidity changes

The suture fatigue test simulates these long-term effects of use.

• It simulates real-world usage conditions: This standard tests two critical situations:
• Seam strength: Instantaneous load (single pull)
• Stitch fatigue: Repetitive stress (years of use)

This ensures the product is suitable for actual customer use.

• It maintains the perception of quality: From the user's perspective,
• Open seams create a perception of low quality.
• Loose threads create an unsightly appearance.

This standard ensures the preservation of aesthetic quality inside the vehicle.

• Meets original equipment manufacturer requirements: Automotive manufacturers,
• They request specific strength values ​​from suppliers.
• We do not accept untested products.

This standard ensures that these requirements are verified.

• It enables design and material optimization: Thanks to the test results,
• The right yarn is selected.
• Stitch type is optimized.
• The fabric structure is improved.

This provides both cost and performance advantages.

In conclusion, the SES N 3247 standard is important because,

• It prevents stitches from breaking or opening.
• It guarantees long-term durability.
• Reduces security risks.
• It preserves the perception of quality inside the vehicle.
• Meets original equipment manufacturer quality requirements.

Without this standard, the reliability of seams in automotive textiles, both in the short and long term, cannot be guaranteed.

In short, this standard evaluates stitching performance in automotive textiles from two perspectives:

• How strong is the stitching?
• How long will the stitches last?

These two tests together guarantee both the immediate durability and long-term performance of vehicle interior textiles.

For many years, our organization, with its competent and experienced team, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting them in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services compliant with the SES N 3247 standard.