ASTM D3167
Floating Roller Peel Test Fixture
Standard Test Method for Floating Roller Peel Resistance of Adhesives - PDF
ASTM D3167 is a standardized peel test method used to measure the bond strength of adhesive joints, specifically using a floating roller fixture to apply a 90-degree peel. It is commonly applied to bonded metal-to-metal or metal-to-composite assemblies in industries such as:
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Aerospace
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Automotive
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Defense
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Industrial adhesives and composites manufacturing
This method is especially useful for high-strength adhesives, where traditional peel tests (like ASTM D903) may not apply due to substrate deformation or excessive peeling force.
What ASTM D3167 Measures
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Average peel resistance over a specified length of bonded material
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Expressed in terms of force per unit width, typically N/mm or lbf/in
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Provides a controlled and reproducible way to measure peel strength of rigid materials
Key Advantages
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Designed for rigid or semi-rigid adherends where flexible peel testing is not suitable
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Floating roller fixture reduces bending stresses and ensures a constant 90° peel angle
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Often more representative of real-world bonded assemblies
Equipment Required
1. Universal Testing Machine (UTM)
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Equipped with a load cell appropriate for the expected peel force (commonly 500 N to 5 kN)
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Capable of maintaining a constant crosshead speed, typically 254 mm/min (10 in/min)
2. Floating Roller Peel Fixture (90-Degree Roller Assembly)
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The roller is unloaded and free-floating, minimizing applied pressure
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Guides the flexible adherend to peel at a constant 90° angle
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Mounted to the UTM base or traveling crosshead
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Constructed to allow low-friction movement and consistent roller alignment
3. Grips
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A mechanical vise grip or pneumatic grip is used to hold the flexible adherend (typically an aluminum or composite foil)
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The rigid adherend is supported on the fixture’s baseplate or clamped horizontally
Specimen Preparation
Sample Construction:
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A flexible adherend (e.g., thin aluminum or composite foil) is bonded to a rigid or semi-rigid panel
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The adhesive layer should be applied as per manufacturer recommendations or internal specifications
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The unbonded tab section of the flexible adherend is left free for gripping
Dimensions:
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Width: Typically 1 inch (25.4 mm), but other widths are acceptable as long as results are normalized
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Length: Sufficient to produce a peel length of at least 127 mm (5 inches)
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Bondline thickness: Should be controlled and recorded (shims can be used if necessary)
Conditioning:
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Standard lab conditions: 23 ± 2°C and 50 ± 5% relative humidity
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Condition specimens for at least 24 hours prior to testing
Test Procedure (Step-by-Step)
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Condition the test samples in the standard lab environment
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Mount the rigid adherend on the base of the peel fixture or secure it horizontally
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Loop the free end of the flexible adherend under the floating roller and clamp it into the upper grip of the UTM
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Set the crosshead speed to 254 mm/min (10 in/min), unless otherwise specified
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Begin the test: the flexible adherend peels away at a constant 90-degree angle as the crosshead pulls upward
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Continue the peel for a minimum of 127 mm (5 inches) to obtain a stable average force
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Record the force vs. extension data throughout the test
Calculated Results
Peel Strength = Average Force ÷ Specimen Width
Where:
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Average Force is measured over a 5-inch (127 mm) segment of peeling
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Specimen Width is the width of the bonded section, in inches or millimeters
Example:
If the average peel force is 20 N and the sample is 25 mm wide:
Peel Strength = 20 N ÷ 25 mm = 0.8 N/mm
Test Report Requirements
Your test report should include:
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Specimen width and bondline thickness
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Average peel strength (N/mm or lbf/in)
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Type and dimensions of adherends
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Adhesive type and application method
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Conditioning time and environment
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Crosshead speed
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Description of failure (adhesive, cohesive, or substrate failure)
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Graph of force vs. displacement (optional but recommended)
Typical Applications
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Structural adhesives used in aerospace and automotive
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Metal foil bonding to composites or rigid plastics
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Testing durability after environmental exposure (heat, humidity, salt spray)
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Adhesive QC testing in production environments
Failure Mode Classification
After testing, examine the peeled surface for failure types:
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Adhesive failure (separation at the adhesive/substrate interface)
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Cohesive failure (failure within the adhesive itself)
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Substrate failure (tearing or fracture of the adherend material)
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Mixed failure (combination of the above)
This can provide insight into whether the adhesive is performing as intended.
Related Standards
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ASTM D903 – Standard peel test for flexible adherends at 180°
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ISO 11339 – Peel test for flexible-to-rigid bonded assemblies
Summary
ASTM D3167 is a specialized peel test method that allows accurate and repeatable evaluation of adhesive bond strength between a flexible and a rigid adherend using a floating roller fixture. It is ideal for applications requiring high-strength adhesive bonding and is widely used in aerospace, automotive, and structural bonding research and production.
By controlling variables like speed, adhesive thickness, and peel angle, ASTM D3167 provides a reliable measurement of peel resistance, helping engineers select the right adhesive for high-performance bonding applications.