Pull-off/Pull-out Testing

Attachments and fixtures are almost always designed to hold within expected limits of force. In construction, an anchor bolt in a wall, an industrial fastener securing two metal plates, a pipe in a transit seal, or a tube on a connector, or a handle or lock, must comply with very rigorous specifications. The strength of electrical wire terminals is tested to international standards, and is a specialist area in itself. Attachments to fabrics similarly must comply with safety requirements, as in soft toys, and with quality standards, as in clothing, to ensure brand protection.

The only way to know that a design and manufacturing process performs as intended, is to physically pull apart regular samples of the finished product.

Essentially, pull-out or pull-off testing is a straightforward tensile test, performed according to certain standards, but more detail than strength to failure can be obtained. In the case of connectors and terminals with soldered joints or weld nuggets, the test to failure involves a break. In the case of a screw fixture or rivet, or a crimped wire joint, the fixing or the conductor may pull out cleanly. It is very important that the sample is held correctly by test fixtures that mimic end use and protect the sample, so a number of specialised fixtures and grips are available. A standard test may require a constant pull speed, or pull at a constant hold force, so a motorised or computer-controlled tester is required, with a calibrated loadcell. Sample elongation and single strand breaks, as well as slippage within the joint are factors that will be seen in the test data.

In a destructive pull test, a contact itself may deform and break, or the conductor within or outside the connector may sever, or the conductor may simply pull out. In a non-destructive pull test, the requirement may simply be to ensure production line samples are well within tolerance. Pass/fail criteria can be set for either, but a sample once tested and passing a non-destructive test may have been weakened and should not be reused.

Types of pull-off test

• Pull-off/Pull-out
• Butt joint
• Parallel plate adhesion

Related test types

Pull-out/pull-off test standards

• ANSI/EIA 364-38B : Cable pull-out test procedure for electrical connectors
• ASTM B571-97 2008e1 : Standard Practice for Qualitative Adhesion Testing of Metallic Coatings
• ASTM B913 -05 : Standard Test Method for Evaluation of Crimped Electrical Connections to 16-Gauge and Smaller Diameter Stranded and Solid Conductors
• ASTM C297 -04 : Standard Test Method for Flatwise Tensile Strength of Sandwich Constructions
• ASTM C907 -98 : Standard Test Method for Tensile Adhesive Strength of Preformed Tape Sealants by Disk Method
• ASTM D429 -08 Standard Test Methods for Rubber Property—Adhesion to Rigid Substrates
• ASTM D816 -06 : Standard Test Methods for Rubber Cements
• ASTM D897 -08 : Standard Test Method for Tensile Properties of Adhesive Bonds
• ASTM D1623 -09 Standard Test Method for Tensile and Tensile Adhesion Properties of Rigid Cellular Plastics
• ASTM D2061-07 : standard test methods for strength tests for zippers
• ASTM D2094 -00 : Standard Practice for Preparation of Bar and Rod Specimens for Adhesion Tests
• ASTM D2095 -96 : Standard Test Method for Tensile Strength of Adhesives by Means of Bar and Rod Specimens
• ASTM D3354 -11 : Standard Test Method for Blocking Load of Plastic Film by the Parallel Plate Method
• ASTM D4541 -09e1 : Standard Test Method for Pull-Off Strength of Coatings Using Portable Adhesion Testers
• ASTM D6958 -03 : Standard Test Methods for Evaluating Side-Bonding Potential of Wood Coatings
• ASTM F543-13e1 : standard specification and test methods for metallic medical bone screws
• ASTM F564 -10 Standard Specification and Test Methods for Metallic Bone Staples
• ASTM F1147 -05 : Standard Test Method for Tension Testing of Calcium Phosphate and Metallic Coatings
• ASTM F1839-08 : standard specification for rigid polyurethane foam for use as a standard material for testing orthopaedic devices and instruments
• BS 7907 : Code of practice for the design and manufacture of children's clothing to promote mechanical safety
• BS 5G 178-1 : Crimped joints for aircraft electrical cables and wires. Specification for design requirements (including tests) for components and tools
• BS EN 2243-4 : Aerospace series. Non-metallic materials. Structural adhesives. Test method. Metal-honeycomb core flatwise tensile test
• BS EN 2591-408:1998 : aerospace series - elements of electrical and optical connection, test methods, mating and unmating forces
• BS EN 2591-412:1999 : aerospace series - elements of electrical and optical connection, test methods, contact insertion and extraction forces
• BS EN 2591-417:2001 : aerospace series - elements of electrical and optical connection. test methods. tensile strength (crimped connection)
• BS EN 2591-418:2001 : aerospace series - elements of electrical and optical connection. test methods. gauge insertion/extraction forces (female contacts)
• BS EN 2591-418:2006 : aerospace series - elements of electrical and optical connection, test methods, mechanical strength of rear accessories
• BS EN 2591-709:2001 : aerospace series - elements of electrical and optical connection, test methods, electrical elements, tensile strength of couplers
• BS EN 3841-509 : aerospace series, circuit breakers, test methods, insertion and extraction forces of signal contact terminals
• BS EN 61300-3-11 : fibre optic interconnecting devices and passive components - basic test and measurement procedures Part 3.11: examinations and measurements - engagement and separation forces
• BS EN 61300-3-33 : fibre optic interconnecting devices and passive components - basic test and measurement procedures Part 3-33: examinations and measurements - withdrawal force from a resilient alignment sleeve using gauge pins
• BS EN 5057 : Specification for flat, quick-connect terminations
• BS EN 15870 : Adhesives. Determination of tensile strength of butt joints
• BS EN 60352-2 : Solderless connections. Crimped connections. General requirements, test methods and practical guidance
• BS EN ISO 4624 : Paints and varnishes. Pull-off test for adhesion
• BS EN ISO 11608-2 : Needle-based injection systems for medical use. Requirements and test methods. Needles
• BS ISO 4919 : carpets - determination of tuft withdrawal force
• DEF STAN 59-71 : Crimped electrical connectors for copper conductors
• DIN 46249 1980-09 : Snap-on connectors, non insulated; requirements, tests
• IEC 60512-13-1 : connectors for electronic equipment - tests and measurements - Part 13-1: mechanical operation tests - test 13a: engaging and separating forces
• ISO 2409 : Paints and varnishes - Cross-cut test
• ISO 6922 : Adhesives - Determination of tensile strength of butt joints
• ISO 9727-5 : Cylindrical cork stoppers - Physical tests - Part 5: Determination of extraction force
• ISO 11502 : Plastics - Film and sheeting - Determination of blocking resistance
• MIL C-39029 /31B : Contacts, electrical connector, pin, crimp removable
• MIL S-23190E : Military specification: straps, clamps, and mounting hardware, plastic and metal for cable harness tying and support
• NASA STD-8739.4 : crimping, interconnecting cables, harnesses, and wiring

See Mecmesin’s range of pull-off/pull-out testers