Strain Gauge Adhesive Selection for Structural Strain Transfer
Structural strain transfer requires minimal bondline thickness, high shear modulus adhesives, and precise surface roughness matching to prevent measurement lag.
Clamping Pressure
Compression Force
Mechanical force applied normal to the bond line ensures intimate contact between substrates during the curing of an adhesive or the lamination of a circuit board. Maintaining consistent clamping pressure prevents the formation of voids and controls the final thickness of the bond. Excessive force might starve the joint by squeezing out too much resin.
Assembly Variable
Uniform distribution of the load across the entire surface area remains a requirement for high quality lamination. Calibration of the press or fixture determines how clamping pressure affects the electrical properties of the finished assembly. Hydraulic or pneumatic actuators often provide the necessary force.
Precise control of the ramp rate prevents the entrapment of air as the resin flows. Monitoring systems track the load throughout the thermal cycle to account for material softening and thermal expansion. Specific load profiles are often programmed into the machine to accommodate different material grades during the cycle.
Bonding Limit
Effectiveness of the bond depends on reaching a specific threshold defined by the adhesive manufacturer. Failure to reach the required clamping pressure results in poor adhesion or delamination during subsequent thermal shocks. Once the resin reaches its gel point the force must remain steady to prevent internal stresses.