PCB pull and shear test

Case study
Tensile pull-off test on an electrical circuit board component with one precision hook fixture made to engage with different PCB elements
Tensile pull-off test on an electrical circuit board component with one precision hook fixture made to engage with different PCB elements
Original test installation with MultiTest tensile/compression testers and the custom PCB shear fixture proof of concept
Original test installation with MultiTest tensile/compression testers and the custom PCB shear fixture proof of concept

Solution

  • Software-controlled force tester and software
  • Adjustable X-Y table to adjust the test piece
  • Custom-designed fastening jig and probes for each individual test

Benefits

  • Semi-automated testing to perform both solder joint IEC tests
  • One machine to meet all requirements

Requirement

A printed circuit board manufacturer wanted to perform both pull and shear tests of surface-mount solder joints according to IEC 62137-1-1 and -2 standards.

The supplier uses skilled technicians to solder very small parts by hand under a microscope, with tweezers and a fine tip soldering iron. The company wanted to undertake controlled checks to maintain quality standards, ensuring components were soldered correctly and would not break off easily when handled.

This required a special holding fixture, which could position the board at 45° and 180° to comply with the specified standards.

Solution

A bespoke solution was designed by Mecmesin to perform both tests. This solution included a universal tester system, 2 loadcells (50N & 500 N), a fastening jig to hold the PCB at a specified angle, and an adjustable X-Y table. Due to the miniature size of the parts to be tested, a special probe and hook were also manufactured.

The fastening jig is used for both tests as it enables the PCB to be positioned at the correct angles. The X-Y table allows fine precision alignment of the board, so that operators gain access to any component on the PCB for testing.

For the pull strength test, the PCB is fastened onto the jig at a 45°angle, and the sample component accurately aligned under the small test hook using the X-Y table. A 50N loadcell was employed to gain the best accuracy for low force measurements. The customer required the pull test to reach a maximum force of 20N for the connections to pass.

For the shear test, the PCB is positioned vertically upon the fastening jig. The special probe is lowered, effectively shearing the sample in compressive mode. A 500 N loadcell was employed for this test as the customer required the shear test to be performed up to 300 N to pass.

Test equipment

  • MultiTest 1-i (replaced by OmniTest and OmniTest Touch UTMs, with VectorPro software)
  • ILC 50N & 500 N loadcells (ELS loadcells for OmniTest)
  • Fastening Jig - accommodates PCB's from 20x20 mm up to 100x160 mm
  • Adjustable X-Y Table (for fine adjustment of PCB)
  • Probe and hook to perform shear and pull tests

Three photos of shearing of PCB components for using a small angled hook on a UTM
The angled fixture locates the PCB test piece to enable the precision probe to compress/shear an element of the board until it dislodges
The test system in a QC lab with an assembly floor in the background
This solution is ideal for quality assurance checks at point of production, testing to several standards on one UTM
Two sets of interchangeable fixtures to pull-off and compress/shear the PCB components
Custom-made interchangeable fixtures were supplied to check the attachment strength under tension and compression/shear as required by the industry standards
Compression tester and fixtures testing electrical PCB component shear off force and a laptop with the test results graph
VectorPro software controls multiple test standard procedures on the same universal tester and multi-function custom jig and interchangeable upper fixtures
Sales agent consulting with customer on test equipment
 

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