Pull-off / Pull-out

Pull-off and pull-out testing are widely used to measure the strength, durability, and reliability of materials, adhesives, coatings, and mechanical fixings. These techniques are essential in industries such as automotive, construction, electronics, aerospace, and packaging, where a failure in adhesion or fastening could lead to costly or hazardous consequences.

Pull-off testing measures the force required to separate a material from a substrate, for example removing a coating from metal or an adhesive from a composite panel. Pull-out testing measures the force needed to extract a fastener, fibre, or other embedded component from its housing.

Both techniques are used to:

• Validate product designs during research and development
• Maintain quality consistency in manufacturing
• Prove compliance with relevant international standards

The versatility of these tests means they are used across a broad range of products and industries.

Adhesive bonding

Pull-off testing ensures adhesive joints in electronics, packaging, or automotive assemblies can withstand operational stresses and environmental exposure. For example, an adhesive securing a display screen must hold under thermal cycling and handling.

Mechanical fixings

Pull-out tests verify that rivets, anchors, and crimped connectors maintain their grip in service. In construction, anchors are tested in concrete or masonry to ensure they can carry specified loads without slippage.

Specialist applications:

• Measuring bristle retention in cosmetic brushes
• Testing medical device assemblies such as catheter hubs and syringe tubing
• Assessing fastening strength in protective clothing

Typical values vary greatly by application. For example, a small electrical crimp connector might require a pull-out force of 20 to 50 N, while a heavy-duty masonry anchor could exceed 15 kN.

Both pull-off and pull-out testing measure tensile strength, which is the maximum load a specimen can sustain under tension before failure.

During testing, a controlled tensile force is applied at a specified rate. The peak force at failure is recorded as the tensile strength. This provides a clear measure of the product’s ability to resist pulling forces in service.

For example, in electrical engineering, a pull-out force requirement ensures a crimped cable terminal will not detach under load. In coatings, pull-off tensile strength is used to confirm adequate surface preparation and coating adhesion.

Testing may be performed destructively or non-destructively depending on the objectives.

Destructive testing applies force until the specimen fails. This is useful for verifying ultimate strength, identifying failure modes, and confirming compliance. It is common in R&D and batch sampling where product sacrifice is acceptable.

Non-destructive testing applies force within safe limits to confirm integrity without damaging the part. This is important for safety-critical or high-value components where the item must remain functional after testing.

Choosing between these methods depends on the product cost, production volume, compliance requirements, and whether destructive testing is permissible.

International standards provide consistent methods and equipment requirements for these tests:

• ASTM D4541 - Pull-off strength of coatings using portable adhesion testers
• ISO 4624 - Paints and varnishes, pull-off test for adhesion
• BS 5080 - Structural fixings in concrete and masonry, resistance to loading
• ASTM F1147 - Tension testing of medical devices
• IEC 60352 - Solderless electrical connections, mechanical pull-out strength

Compliance with these standards ensures consistent test results, product safety, and market acceptance.

Accurate and repeatable testing depends on precision equipment and well-designed fixtures. Key components include:

• Force testers capable of applying tensile loads at controlled rates
• Load cells matched to the expected force range, calibrated regularly
• Custom fixtures and grips to secure the specimen without slippage or damage
• Data acquisition systems to record force peaks and produce test curves

Fixtures should be adaptable for different geometries, from small adhesive bonds to large mechanical anchors. Calibration of both load cells and fixtures is essential to meet standard requirements and maintain repeatability.

Mecmesin designs and manufactures tensile and adhesion testing equipment for both destructive and non-destructive pull-off and pull-out applications. Our systems are used worldwide to test everything from delicate medical devices to high-strength construction fixings.

Technical advantages include:

• Systems such as the OmniTest, MultiTest-dV, and Vortex ranges covering a wide range of force capacities
• VectorPro software for advanced data capture, analysis, and reporting
• Compliance with ASTM D4541, ISO 4624, BS 5080, ASTM F1147, and IEC 60352
• Customisable fixtures and grips for non-standard shapes and materials
• High-precision load cells for accurate measurement and traceable results

For example, a manufacturer of automotive wiring harnesses uses Mecmesin pull-out testing systems to ensure crimped terminals meet strict tensile strength requirements, improving product reliability in demanding operating environments.

For guidance on implementing pull-off and pull-out testing in your quality control or R&D process, speak to one of our technical experts today. We can help you select the right equipment, fixtures, and standards to ensure your products meet performance, reliability, and compliance targets.