ASTM F2606 Three-Point Bending Test for Balloon-Expandable Vascular Stents and Stent Systems

Information on the most widely used ASTM standards within the materials testing industry

Descriptions of the most prominent lSO standards within the materials testing industry

Standards including EN, DIN, JlS, and more

Mechanical testing of polymer materials in the automotive industry is directly related to the safety of components and the reliability of the entire vehicle. UnitedTest can cover mechanical performance testing for automotive interior and exterior parts, as well as functional components, adapting to automaker standards and providing comprehensive testing solutions including tensile, impact, and fatigue tests.

Mechanical testing in the battery industry determines the tensile and puncture resistance of core components such as separators and electrodes, directly affecting battery safety and cycle life. UnitedTest can cover full-dimensional mechanical testing of battery materials, compatible with national and international standards, and provide customized testing solutions.

Mechanical testing in the consumer goods industry determines product durability and safety, such as impact resistance for toys and fatigue resistance for home appliances, making it core to compliance and quality. UnitedTest can cover mechanical tests for all categories of consumer goods, including tensile, impact, and hardness tests, compatible with national and international standards, and offers customized testing solutions.

In the field of medical and biomedical sciences, mechanical testing determines the safety and compatibility of implanted devices and biomaterials, making it a core part of regulatory approval. UnitedTest can cover a full range of tests including tensile, fatigue, and wear tests, compatible with national and international standards, and provides customized biomechanical testing solutions.

Material strength is a course that most engineering fields are required to study in university education. This interesting course is very practical and makes use of testing equipment in the materials laboratory.

Mechanical testing of industrial products and components is essential to ensure their load-bearing, fatigue resistance, and impact resistance, directly preventing production accidents and ensuring stable operation of equipment. UnitedTest can cover a full range of tests including tensile, hardness, and fatigue, complying with national and international standards, and provides customized industrial mechanical testing solutions.

Mechanical testing in the plastic pipe industry determines ring stiffness, impact resistance, and tensile performance, directly preventing pipe bursts and deformation risks. UnitedTest can cover full-dimensional mechanical testing of pipes, complies with ISO,ASTM,EN et.c, international standards, and provides customized testing solutions.

In the construction engineering and building materials industry, mechanical testing determines the compressive and tensile properties of materials such as concrete and steel, which is core to ensuring the safety and durability of buildings. UnitedTest can cover the full range of building material mechanical tests, complies with ISO, ASTM international standards, and provides customized testing solutions for compressive, tensile, and other properties.

Mechanical testing in the food and beverage industry involves the compressive and tensile performance of packaging and the safety of food texture, directly ensuring storage, transportation safety, and the eating experience. UnitedTest can cover all-dimensional mechanical testing for packaging and food texture, comply with national and international standards, and provide customized testing solutions.

Mechanical testing in the packaging industry determines the packaging's resistance to compression, impact, and tension, directly ensuring the safety of contents during storage and transportation. UnitedTest can cover comprehensive mechanical testing for packaging, complying with ISO, ASTM Standards, and provides customized testing solutions for compression, drop, tear, and more.

Mechanical testing in the transportation industry concerns the load-bearing and fatigue resistance performance of core components such as vehicles, tracks, and containers, directly ensuring transport safety and equipment durability. UnitedTest can cover mechanical testing for all types of transportation materials, complying with national and international standards, and provides customized testing solutions including tensile, fatigue, and impact tests.

Metallurgical testing examines the properties of metallic materials to determine if a particular metal is appropriate for its intended use.

Testing of polymer materials covers mechanical, thermal, and chemical properties, verifying strength, heat resistance, composition, and ensuring product quality and compliance.

UnitedTest offer world-class testing solution in testing for polymeric materials, including elastomers, thermoplastics, composites, coatings, and structural adhesives in a variety of industries.

Testing of rubber and elastomers is used to assess the various properties and performance of materials under different conditions. This is crucial for ensuring the safety, functionality, and quality of rubber and elastomer products used in industries such as automotive, construction, consumer goods, and aerospace.

Conduct adhesive testing using various testing methods to determine their performance and characteristics in applications across multiple industries such as aerospace, automotive, construction, packaging, industrial, medical, and energy, thereby supporting application development and quality assurance.

UnitedTest supply machine and testing solution for tension, compression, fracture toughness, direct shear, triaxial and ultrasonic velocity are common concrete and rock testing applications.

UnitedTest has helped a number of companies involved in the wood, paper, cardboard, and corrugated industry with their testing needs. Our materials testing systems are capable of testing raw materials, components, and finished products.

UnitedTest testing system is trusted by leading medical device manufacturers, universities, and medical research laboratories worldwide. Whether testing tissues or bioresorbable materials, stents, or sutures, UnitedTest offers a variety of single-actuator and dual-actuator systems to meet your biomedical testing needs.

Mechanical testing in the textile fabric industry determines core properties such as fabric tensile strength, tear resistance, and wear resistance, directly affecting product durability and safety. UnitedTest can cover comprehensive mechanical tests for textiles, complying with national standards / ISO standards, and provides customized testing solutions including tensile, tear, and puncture tests.

The mechanical testing of industrial components directly determines the load-bearing, fatigue resistance, and wear resistance of the parts, helping to avoid equipment failure risks. UnitedTest can cover a full range of tests including tensile, hardness, and fatigue, is compatible with ISO/ASTM/GB standards, and provides customized mechanical testing solutions for industrial components.

Mechanical testing in the glass-ceramics industry determines core properties such as flexural strength, hardness, and fracture toughness, directly helping to avoid brittleness and failure risks. UnitedTest can cover comprehensive testing for flexural strength, hardness, and fracture toughness, compatible with national and ISO/ASTM standards, and provides customized testing solutions.

Tensile test evaluates material resistance to stretching, measuring strength/elongation critical for quality control. UnitedTest offers universal tensile testers (10-600KN) compliant with ASTM/ISO standards, providing tailored solutions for metals, polymers, medical & industrial materials.

Compression test assesses material resistance to compressive loads, measuring strength/deformation critical for quality validation. UnitedTest offers compression testing machines compliant with ASTM/ISO standards, providing tailored solutions for concrete, plastics, metals and industrial components.

Flexural & Bend tests evaluate material resistance to bending forces, measuring strength, stiffness and ductility for quality assurance. UnitedTest provides flexural testing machines (3-point/4-point bend) compliant with ASTM/ISO standards, offering tailored solutions for composites, plastics, metals and construction materials.

Torsion Test evaluates material resistance to rotational forces, measuring torsional strength/ductility critical for fasteners, insulators, shafts. UnitedTest offers torsion testers compliant with ASTM A938/ISO 16047, providing tailored solutions for automotive, aerospace, fastener industries.

Fatigue Test assesses material durability under cyclic loading, critical for predicting service life of industrial components. UnitedTest offers fatigue testing systems (axial/bending/torsion) compliant with ASTM E466/ISO 12106, providing tailored solutions for automotive, aerospace and manufacturing sectors.

Peel Test measures material adhesion strength by evaluating resistance to peeling forces, critical for adhesives, films, packaging. UnitedTest offers peel testers compliant with ASTM D903/ISO 8510, covering 90°/180° peel tests, and tailored solutions for packaging, automotive, textile industries.

Impact Test evaluates material resistance to sudden shock loads, critical for assessing toughness and fracture risk. UnitedTest offers impact testers (Charpy/Izod/fall weight) compliant with ASTM E23/ISO 148, providing tailored solutions for metals, plastics, glass and industrial components.

Tear & Shear Test evaluates material resistance to tearing and shearing forces, measuring critical strength parameters for quality control. Tear tests (Elmendorf/trouser/trapezoidal) assess resistance to crack propagation in films/fabrics, while shear tests measure resistance to parallel forces in joints/bolts. UnitedTest provides universal testing machines (10KN-600KN) with specialized fixtures for both tests, compliant with ASTM D624/D3164 and ISO standards, serving automotive, packaging and construction industries.

Hardness test measures material's resistance to permanent indentation, critical for quality control. UnitedTest offers universal hardness testers (Rockwell/Brinell/Vickers) compliant with ASTM/ISO standards, plus tailored hardness testing solutions for diverse industrial needs.

Biaxial/triaxial tests evaluate material performance under multi-axis loads, critical for biomaterials, metals and composites. UnitedTest provides compliant testing machines (ASTM/ISO) for planar biaxial, static/fatigue triaxial tests, with tailored solutions for industrial & biomedical needs.

Friction and wear tests assess material resistance to friction, abrasion and wear, critical for industrial material performance validation. UnitedTest offers tribometers compliant with ASTM G99/ISO standards, covering pin-on-disk, four-ball tests, and tailored friction & wear testing solutions for diverse industries.

Pressure test evaluates material/component resistance to static/dynamic pressure, critical for sealing, strength and safety validation. UnitedTest offers pressure testing machines compliant with ASTM/ISO standards, covering burst, hold-pressure tests, and tailored solutions for industrial, automotive & medical sectors.

Fire test assesses material flammability, heat resistance and fire-retardant performance, critical for safety compliance across industries. UnitedTest offers fire testing equipment compliant with ASTM/ISO/UL standards, providing tailored fire test solutions for building materials, plastics and industrial components.

Non-destructive Test (NDT) evaluates material/component integrity without damage, critical for safety & quality across industries. UnitedTest offers ultrasonic/X-ray/magnetic particle NDT equipment compliant with ASTM/ISO standards, plus tailored NDT solutions for aerospace, automotive & manufacturing sectors.

ASTM F2606 Standard Guide for Three-Point Bending of Balloon-Expandable Vascular Stents and Stent Systems.

ASTM F2606 defines quantitative three-point bending procedures to characterize the bending flexibility and stiffness of balloon-expandable vascular stents and stent systems (pre-deployment and deployed states). It is a critical testing protocol in the biomedical engineering field. Since vascular anatomies are naturally curved and tortuous, a stent must be flexible enough to navigate through the delivery pathway (trackability) and conform to the vessel's curvature once deployed without causing vascular trauma . This standard provides the guidelines to measure these mechanical properties accurately.

Test Principle:

The test operates on the classic three-point bending mechanical principle. The specimen (stent or stent system) is placed on two parallel lower static supports (creating a "span"). A vertical load is then applied midway between these supports by an upper dynamic load applicator, causing the specimen to bend. By measuring the applied force and the resulting deflection, the bending flexibility and stiffness of the test article can be quantitatively determined.

ASTM F2606 Three-Point Bending Test for Balloon-Expandable Vascular Stents and Stent Systems

Specific Test Methods:

The standard outlines two primary methods for conducting the three-point bending test, differing mainly in how the span length is handled :

Fixed Span Length Method	The distance between the lower supports remains constant.
	Advantage:Allows for direct force-vs-deflection comparisons independent of stent length. Useful for comparing stents of different diameters or designs, and allows for evaluating flexibility at multiple points along a long stent.
Variable Span Length Method	The span length changes based on the specimen's length (e.g., 10-14 mm stents use a 10 mm span, while >35 mm stents use a calculated span).
	Advantage:Maximizes the bending moment arm for any given stent length, minimizing the risk of non-bending deformation (like kinking or crushing) at a given load. Comparisons are made by evaluating midspan bending moments at given curvatures.

ASTM F2606 Required Test Equipment & Apparatus

Recommend UnitedTest Universal testing machine + 3 points bending fixture for vascular stent.

Loading Test Machine

Capable of applying a controlled, constant deflection rate vertically. It must have adequate displacement rate control to avoid inertial effects.

Three-Point Bend Fixture

Consists of two lower static supports and one upper dynamic load applicator.

Support Dimensions: Typically, the supports are cylinders with a diameter of 6.35 mm (1/4 inch).

However, alternative geometries/materials (like Teflon or Delrin) can be used to minimize adverse friction or localized stent crushing.

Grooves or shoulders may be added to the lower supports to keep the specimen perpendicular during the test.

Environmental Controls

(Optional but recommended): Means to maintain the test article at 37 ± 2°C (simulating body temperature) and keep it fully hydrated.

Test Specimen Information

Quantity: Minimum 3 identical specimens (same labeled diameter/length) per test condition; more samples may be needed for performance claims.

Specimen types: Pre-deployment stent systems, deployed stents, and standalone delivery systems.

Orientation: Test maximum/minimum bending stiffness orientations if properties are rotation-sensitive.

Variable-span selection: Shortest stents for maximum bending load; longest stents for minimum bending load.

Exclusion: Not for self-expanding stents, stent-grafts, or specimens with span-to-OD ratio <4:1.

Key Test Parameters

Parameter	Requirement
Span length	Fixed span: ≥4 mm smaller than the minimum stent length Variable span: According the standard requirement (10–14 mm stent: 6D span; >35 mm: (length/1.093)−2).
Maximum deflection	The vertical displacement applied by the upper load applicator. Variable span: 1.2 mm (10–14 mm stent) to 0.2×span (>35 mm stent)
Deflection rate	Must be constant and slow enough to avoid excessive inertial loads. Should be consistent when comparing different devices.
Preload	0.005–0.200 N to ensure three-point contact

Test Stipulations (Rules & Validity)

No Retesting: If a stent deforms during a test, it must be discarded. Even if no deformation is visible, retesting is discouraged as prior loading affects the material properties .

Data Validity: The test results are considered invalid if:

The specimen exhibits substantial non-uniform bending.

Localized kinking, buckling, or crushing is observed (slight uniform ovalization is acceptable).

Appreciable elongation of the test article occurs during loading .

Data Analysis: Force vs. Deflection curves should be plotted. For valid flexibility comparisons, the slope of the linear region (R² ≥0.9) is used. A lower slope indicates greater bending flexibility.

ASTM F2606 Vascular stent three-point bending Test Procedures:

Preparation	Set up the fixture. Mark the midpoint of the stent for load application. Cut the stent system or deploy the standalone stent as required.
Conditioning	If required, preheat the fixture and specimen to 37 ± 2°C and ensure full hydration.
Positioning	Place the specimen centrally on the lower supports, ensuring the upper applicator will hit the marked midpoint.
Zeroing	Balance the force transducer. Apply a slight preload or account for the initial gap.
Execution	Apply the vertical load at a constant deflection rate until the maximum desired deflection is reached. Record force and deflection continuously. Unloading data should also be recorded at the same rate to check for elastic recovery.
Inspection	Visually inspect the specimen post-test for kinking, buckling, or crushing.
Calculation	Correct the raw data for preload/gap. Calculate Midspan Bending Moment (M=PL/4) and Midspan Curvature (κ=12δ/L²) if using the variable span method.

Test Application (Industry Field)

Core field: Cardiovascular/vascular medical device industry for balloon-expandable vascular stents and stent delivery systems.

Extended use: Non-vascular balloon-expandable stents.

Purpose: R&D characterization, material/design comparison, and quantitative evaluation of bending performance for regulatory and product optimization.

Related Standards

ASTM F2477	Standard Test Methods for in vitro Pulsatile Durability Testing of Vascular Stents and Endovascular Prostheses
ASTM F2516	Standard Test Method for Tension Testing of Nickel-Titanium Superelastic Materials
ASTM F3067	Standard Guide for Radial Loading of Balloon-Expandable and Self-Expanding Vascular Stents
ISO 25539-2	Cardiovascular implants - Endovascular devices - Part 2: Vascular stents

A single column tensile tester is a sophisticated material testing instrument designed for measuring mechanical properties of various materials under tension, compression, bending, shear, and other loading conditions. As the name suggests, it features a single vertical column supporting a moving crosshead that applies force to test specimens.

WDW Series Computer Control Electronic Universal Testing Machine made by UNITEDTEST range from 100N to 600KN load capacity with various models like single columns, table type, door frame type etc., is used to perform tension, compression, flexure/bending, shearing, peeling etc., test for metal and nonmetal specimens. Matched with UNITEDTEST design and produced various test fixture, like peel, flexure, puncture, tear, pneumatic grip, belt tension etc., this UTM can be used to almost all materials include but not limited to steel rod, rubber, steel wire, plastic, seat belt, textile, wood, panel etc., mechanical performance inspection.

Three-Point Bending Test fixture for Vascular Stent is a specialized mechanical testing instrument designed to evaluate the flexural properties of balloon-expandable vascular stents and stent system. Conform with ASTM F2606, ISO 25539-2.

Q1: What exactly is the ASTM F2606 test?

A: Simply put, it is a standardized, scientific method for measuring how well a balloon-expandable vascular stent or stent system can bend without breaking or deforming. It uses a "three-point bending" setup—imagine placing a tiny bridge (the stent) on two pillars and gently pressing down on its center until it curves. By measuring the force required to bend it, we get a clear, objective score of its flexibility .

Q2: Why is this test so important for vascular stents?

A: Think of the human vascular system—it’s not a straight pipe; it’s full of curves and twists. A stent needs to be rigid enough to hold open a blocked artery, but flexible enough to bend naturally as the patient moves, breaths, or walks. If a stent is too stiff, it can cause vessel trauma, discomfort, or even fracture over time. This test quantitatively proves that the stent can safely navigate and adapt to the body's natural anatomy .

Q3: Does the test setup change based on the size of the stent?

A: Yes, absolutely. The standard offers two main approaches:

Fixed Span Method: The distance between the two bottom supports stays the same. This is great for comparing stents of different lengths or designs directly against each other .

Variable Span Method: The distance between the supports changes depending on the stent's length (as outlined in Table 1 of the standard). This maximizes the bending effect and minimizes the risk of the stent simply crushing or buckling rather than bending.

Q4: What mandatory information is in the test report?

A: Specimen details (part/lot number, dimensions), test type (stent system/deployed stent), span/deflection/rate, temperature/hydration, force-deflection and moment-curvature curves, slope/R² values, deformation observations, and statistical data (mean, standard deviation).

Q5: Can I reuse a stent for another test if it didn't break?

A: No. The standard strictly advises against retesting. Even if the stent looks perfectly fine to the naked eye, the microscopic structure of the metal (or polymer) may have already been altered or fatigued by the initial bend. Using it again will give you inaccurate, compromised data .

Q6: What makes a test result "invalid"?

A: You have to watch the stent very carefully during the bend. A result is thrown out if the stent doesn't bend smoothly. For example, if it suddenly kinks, buckles, crushes, or stretches noticeably, the data is no longer reflecting pure "flexibility"—it's reflecting a failure mode.

Q7: Why must the test temperature be controlled at 37±2 °C?

A: This simulates human body temperature. Bending properties of many stent materials change with temperature; testing at 37 °C ensures data reflects in vivo performance.

Q8: Can I use this test for heart valve stents or aortic aneurysm stents (stent-grafts)?

A: Not directly. ASTM F2606 is highly specialized for balloon-expandable vascular stents (like those used in coronary arteries). It is not recommended for self-expanding stents, endoprostheses (stent-grafts), or heart valves. However, the core principles of three-point bending described in the guide could serve as a helpful starting point if you were developing a custom test for those other devices .

Q9: Does passing this test guarantee the stent will work perfectly in a patient?

A: Not entirely on its own. This test specifically measures bending flexibility. While crucial, a stent's overall safety and efficacy also depend on other factors like its radial strength (resistance to compression), its fatigue life (how long it lasts), and its trackability (how easily it navigates through blood vessels before deployment). The ASTM F2606 is one vital piece of a much larger puzzle .

We offer customization to meet your specific needs. Our expert team will collaborate with you to develop the perfect product for you