Strain gauges for PCB reliability testing

Test & Measurement

12 August 2015 Test & Measurement Manufacturing / Production Technology, Hardware & Services

Micro-Measurements released three new small-scale strain gauges designed to meet the growing demand for precise, stable and reliable stress analysis of PCBs, even in harsh environments.

The C2A-06-G1350-120 rectangular rosette gauge and C2A-06-015LW-120 uniaxial linear gauge are designed to detect PCB surface strains at critical locations in consumer electronics.

The miniaturisation of consumer electronics – and consequent increase in component density – results in larger thermal stresses, new requirements for surviving repeated loadings, and a greater need for impact stress survival. Meeting these specifications requires accurate knowledge of strains in the PCB and on-board components. Strain gauge measurement is the quickest, most accurate and most cost-effective method for identifying strains on a PCB, and can be used in developing loading fixtures and test plans to optimise the testing phase.

The C2A-06-G1350-120 is a stacked rosette gauge with a compact 5 mm diameter matrix and 3 m of three-conductor cable to eliminate lead wire soldering after bonding. Micro-Measurements’ Advanced Sensors strain gauge technology makes even smaller planar rosettes possible for use in surface mounting applications with restricted areas, as well as for intra-laminar strain measurement.

The uniaxial linear C2A-06-015LW-120 is supplied with pre-attached cables and features an active grid length of just 0,381 mm and an overall matrix of 1,4 x 1,9 mm. The device is ideal for installation on surface-mount components.

Cracks in the PCB and even across components, particularly around BGAs, can be induced by in-circuit test fixtures and during assembly, burn-in and testing, system integration, and packaging and shipping. Strain measurements should be made after all design iterations of the PCB, including changes to on-board components, which may alter thermal stress loading.

Combined with Micro-Measurements instrumentation and StrainSmart software, these strain gauges and accessories for PCB testing are IPC/JEDEC-9704 compliant and provide real-time data acquisition of board and component strains. This is especially useful when introducing new solder materials and processes, which may have a different stiffness and introduce a different soldering thermal profile.

For more information visit www.vishaypg.com/micro-measurements

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Strain gauges for PCB reliability testing

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