Binding Tape Testing

Cable tie testing mainly conducts scientific testing and analysis on tensile strength and elongation at break testing, self-locking force retention performance testing, high and low temperature resistance testing, flame retardancy testing, weather resistance and aging resistance testing, and chemical medium corrosion resistance testing, objectively assessing the product quality grade and issuing a detailed test report, providing a basis for manufacturers' quality control and downstream users' product acceptance.

Testing Items

Tensile strength and elongation at break testing: This is the core item for evaluating the mechanical properties of cable ties. During the test, the cable tie sample is fixed on a tensile testing machine and stretched at a constant speed until breakage. By recording the maximum tensile force and the elongation at breakage, the tensile strength (the maximum tensile force per unit cross-sectional area) and the elongation at break are respectively calculated, so as to judge whether the material meets the load-bearing requirements and the expected service life.

Self-locking force retention performance testing: This item simulates the long-term fastening effect of the cable tie in actual use. The cable tie is locked on a mandrel of a standard diameter in the specified manner, placed in a specific temperature and humidity environment and kept for a certain time (such as 24 hours or longer), and then the decay rate of its locking force is measured. This indicator is directly related to whether the cable tie will become loose and fail under conditions such as vibration and temperature changes.

High and low temperature resistance testing: Tests the performance stability of the cable tie under extreme temperature environments. The samples need to be placed separately in a high-temperature chamber (such as 85 ℃, 105 ℃ or 125 ℃) and a low-temperature chamber (such as -40 ℃ or -55 ℃) for the specified duration, and then the appearance changes (such as embrittlement, softening and deformation) are observed and tensile or bending tests are immediately carried out, evaluating the retention rate of its mechanical properties and ensuring that it works reliably in a wide temperature range.

Flame retardancy testing: For fields with fire protection requirements such as electronics, electrical appliances, automobiles and aerospace, flame retardancy is crucial. Tests are usually carried out in accordance with standards such as UL 94 and IEC 60695. Through vertical burning or horizontal burning tests, the burning rate, extinguishing time and whether dripping occurs of the sample are evaluated, and the corresponding flame retardancy grade (such as V-0, V-1, V-2 and HB) is classified.

Weather resistance and aging resistance testing: Evaluates the performance decay of the cable tie under the long-term action of environmental factors such as sunlight, ultraviolet rays and ozone. A xenon lamp aging test chamber or UV aging test chamber is mainly used to simulate outdoor light conditions. After hundreds to thousands of hours of accelerated aging, its colour change, surface chalking and mechanical property degradation are detected, predicting its outdoor service life.

Chemical medium corrosion resistance testing: Tests the performance changes of the cable tie after contact with specific chemicals (such as acids, alkalis, salts, oils and solvents). The sample is completely or partially immersed in the specified chemical reagent, taken out after the specified temperature and duration, cleaned and wiped dry. By observing the appearance changes (such as swelling, dissolution and cracking) and testing the mechanical property retention rate, its applicability in specific industrial environments is judged.

Testing Scope

Material types: Testing covers cable ties made of different polymer materials, the most common of which include nylon (PA6, PA66), polypropylene (PP), polyethylene (PE) and special engineering plastics (such as PEEK and PVDF). Different materials determine their basic properties. For example, nylon ties have high strength and wear resistance, and polypropylene ties are resistant to acids and alkalis. Testing needs to set corresponding items and standards according to their material characteristics.

Product types and application fields: The testing scope includes general-purpose plastic cable ties, self-locking cable ties, releasable cable ties, identification cable ties, heavy-duty bundling ties and UV-resistant cable ties. The application fields cover wire harness bundling of electronics and electrical appliances, automobile wire harness fixing, construction bundling, agriculture and horticulture, logistics packaging, as well as high-end industrial fields such as aerospace and rail transit. Different fields have different testing focus and strictness.

Specifications and dimensions: Testing needs to cover cable ties of different specifications, mainly classified according to their width, thickness and length, for example from micro ties (2.5 mm wide) to ultra-heavy-duty ties (over 19 mm wide). The key indicators such as the rated tensile strength and working temperature range of products of different specifications are different, and samples and fixtures of the corresponding specifications must be used during testing.

Certification compliance: The testing scope also points to the various international, national or industry standards and certification requirements that the product needs to meet. For example, products exported to the EU need to comply with the RoHS and REACH regulations; products used in automobiles need to meet the relevant automotive OEM standards (such as TL, VW and Ford); products used in electronics and electrical appliances need to comply with UL certification; products used in rail transit may need to meet the EN 45545 fire protection standard.

Production process quality control: Testing is not limited to finished products, but also extends to the production process. This includes the melt flow index and moisture content testing of raw materials (such as plastic pellets); the inspection of product dimensional tolerances and appearance defects (flashing, flash, bubbles and short shots) after injection molding; and sampling tests of the engagement function of the self-locking head structure, ensuring production consistency.

Failure analysis and life assessment: Professional failure analysis is carried out for cable tie products with quality problems in the market or with breakage and loosening during use. Through means such as macroscopic morphology observation, scanning electron microscope (SEM) analysis of the fracture surface, FTIR analysis of material degradation and DSC analysis of the thermal history, the root cause of the failure is traced, providing data support for the product life assessment.

Testing Methods

Static mechanical property test method: Mainly in accordance with plastic tensile property test standards such as ASTM D638, ISO 527 and GB/T 1040. A universal material testing machine is used to stretch dumbbell-type or strip specimens at a constant crosshead separation speed (such as 50 mm/min or 100 mm/min) until breakage. The system automatically records the force-displacement curve, and calculates key parameters such as the tensile strength, elongation at break and modulus of elasticity.

Dynamic fatigue test method: Used to evaluate the durability of cable ties under alternating loads. The locked cable tie is installed on a fatigue testing machine, and a periodic tensile force lower than its static tensile strength (such as an amplitude of 30%-70% of the rated load) is applied for millions of cycles, checking whether cracks, breakage or locking mechanism failure occurs, simulating the vibration environment in actual use.

Environmental stress cracking (ESC) test method: Aimed at the characteristics of some plastics (such as PE and PP) that are prone to cracking under the combined action of stress and chemical media. A bending fixture is commonly used to apply a constant bending strain to the cable tie, and then it is immersed in a surfactant (such as Igepal) or other specific reagents. At the specified temperature, the time for the appearance of cracks is observed and recorded, evaluating its resistance to environmental stress cracking.

Thermal analysis test method: A differential scanning calorimeter (DSC) is used to determine the glass transition temperature (Tg), melting temperature (Tm) and crystallinity of the cable tie material; a thermogravimetric analyser (TGA) is used to determine the thermal decomposition temperature and component content of the material. These data are important bases for judging the temperature resistance grade, processability and identification of the raw material types of the material.

Spectroscopy and chromatography analysis method: Fourier transform infrared spectroscopy (FTIR) is used for the "fingerprint" identification of the cable tie material, confirming its main chemical composition and whether there are foreign impurities or degradation products. Gas chromatography-mass spectrometry (GC-MS) is used to analyse the additives such as plasticizers and flame retardants that may be contained in the material and their contents, ensuring compliance with environmental regulations (such as RoHS and REACH).

Simulated working condition test method: Customized tests are designed according to the specific application scenarios of the cable tie. For example, automobile wire harness ties need to undergo salt spray tests, thermal shock tests and oil immersion tests; outdoor ties need to undergo comprehensive climatic tests such as UV aging, spray and damp heat cycling; heavy-duty bundling ties need to undergo long-term static load retention tests, verifying their long-term reliability.

Testing Standards

Domestic Standards:

1. GB/T 1040.1-2018, Plastics — Determination of tensile properties — Part 1: General principles

2. GB/T 9341-2008, Plastics — Determination of flexural properties

3. GB/T 2406.2-2009, Plastics — Determination of burning behaviour by oxygen index — Part 2: Ambient-temperature test

4. GB/T 16422.2-2014, Plastics — Methods of exposure to laboratory light sources — Part 2: Xenon-arc lamps

International Standards:

1. ISO 527, Plastics — Determination of tensile properties

2. ISO 178, Plastics — Determination of flexural properties

3. UL 94, Tests for flammability of plastic materials for parts in devices and appliances

Note: The applicable standard can be selected according to the product use and customer trade requirements; standards agreed in the contract take precedence over general standards.

Testing Instruments and Equipment

Universal material testing machine: The core mechanical testing equipment, equipped with a high-precision force sensor and displacement sensor, used for tensile, compression, bending, shear and other tests. For cable tie testing, dedicated flat-jaw fixtures or cable fixtures, as well as a special mandrel fixture for testing the self-locking force, need to be equipped. The equipment software should be able to automatically calculate and export various mechanical property indicators.

High and low temperature alternating test chamber: The key equipment for evaluating the temperature resistance of cable ties. It can precisely control the temperature range in the chamber (such as -70 ℃ to +150 ℃ or wider), and achieve rapid heating and cooling rates, carrying out high and low temperature storage tests and thermal shock tests. Advanced models can also integrate humidity control functions for constant temperature and humidity or damp heat cycling tests.

Xenon lamp/UV aging test chamber: Equipment for simulating the influence of sunlight and ultraviolet rays on material aging. The spectrum of the xenon lamp aging chamber is closest to sunlight, and can simultaneously control parameters such as the light intensity, chamber temperature, black panel temperature and spray humidity. The UV aging chamber (such as with UVA-340 lamps) is mainly used to accelerate the UV aging test of the material, with higher efficiency, and is commonly used for quality comparison and control.

Flame retardancy tester: Depending on the standard, the equipment varies. The vertical/horizontal burning tester is equipped with a Bunsen burner, specimen holder, timer and measuring scale for UL 94 tests. The limiting oxygen index (LOI) tester quantitatively evaluates the flame retardancy of the material by measuring the minimum oxygen concentration required for the material to maintain combustion in a nitrogen-oxygen mixed gas; the higher the value, the better the flame retardancy.

Image measuring instrument/tool microscope: Used for the precise measurement of the geometric dimensions of cable ties, such as the width, thickness, tooth pitch and internal dimensions of the lock. Through a high-magnification lens and CCD imaging system, combined with professional measurement software, the equipment can realize rapid and precise non-contact measurement and generate inspection reports. It is an important tool for controlling the dimensional tolerances of the product and the mold wear condition.

Thermal analysis and spectroscopy analysers: Including a differential scanning calorimeter (DSC), thermogravimetric analyser (TGA) and Fourier transform infrared spectrometer (FTIR). These precision analytical instruments are used to deeply investigate the micro thermal properties, composition and chemical structure of the cable tie material, providing scientific data support for material R&D, incoming material identification, failure analysis and process optimization.