Miniature Strain Gauge Developed for Autonomous Vehicles and Robotics

By Mike Ball / 28 Sep 2018
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Vishay Miniature Strain Gage Sensor

Vishay Precision Group‘s Micro-Measurements brand has announced the introduction of the G1350 C2K-Series strain gauge, a miniature stacked rectangular rosette sensor built to meet the developing need for precise, consistent, and reliable stress analysis of PCBs, even in severe environments. The G1350 is designed to detect PCB surface strains at critical locations. It is ideal for applications in Industrial Internet of Things (IIoT), autonomous vehicles, and robotics and others that can benefit from its small size and higher resistance of 120 ohms and 350 ohms.

Designed using the same rigorous standards as traditional Micro-Measurements gauges, the new line of C2K series strain gauges is based upon advanced technology manufacturing processes that allows high resistance in small-sized gauge patterns. The uniaxial linear stacked rosette C2K-06-G1350-350 features an active grid length of 0.040” and an overall matrix of 0.20” diameter to allow spot-on installation on surface-mount components. The 3 meters of pre-attached three-conductor cable is built to ease and speed-up installation processes by eliminating the need of lead wire soldering after bonding.

Miniaturizing electronics will result in higher component density, increased thermal stresses, new requirements for surviving repeated loadings, and a larger need for impact stress survival. In order to meet these requirements, precise knowledge of strains in the PCB and on-board components is a must. The most accurate, swift, and cost-effective manner to detect strains on a PCB is through strain gauge measurement, which can also be used in developing loading fixtures and test plans to optimize the testing phase.

The new strain gauge features a Modified Karma, or K-alloy (C2K), and an epoxy overcoat for grid encapsulation. The second generation of the G1350 is based on K-alloy, with its extensive areas of application, representing a vital member in the family of strain gauge alloys for PCB testing. Categorized by strong fatigue life and excellent stability, K-alloy strain gauges can be exposed to temperatures as high as +150°F (+66°C). An inert atmosphere will strengthen stability and extend the useful gauge life at high temperatures. Among its other advantages, K-alloy offers a much flatter thermal output curve than A-alloy, allowing more precise correction for thermal output inaccuracies at temperature extremes. Like constantan, K-alloy can be self-temperature-compensated for use on materials with different thermal expansion coefficients. K-alloy is the normal selection when a temperature compensated gauge is required that has environmental capabilities and performance characteristics not attainable in A-alloy gauges.

As required by standards in the electronics industry, PCAs must be tested to determine if the design can withstand the rigor of manufacturing, packaging, transporting, and day-to-day use of electronic devices. Some of the methods in the process in which strain gauges are used for printed circuit assembly testing include: ensuring appropriate surface preparation materials are on hand, selecting an adhesive, selecting a protective coating that will resist environmental conditions, and selecting the measurement instrumentation.

Posted by Mike Ball Mike Ball is our resident technical editor here at Unmanned Systems Technology. Combining his passion for teaching, advanced engineering and all things unmanned, Mike keeps a watchful eye over everything related to the unmanned technical sector. With over 10 years’ experience in the unmanned field and a degree in engineering, Mike’s been heading up our technical team here for the last 8 years. Connect & Contact