Minimizing Circuit Board Strain Propagation in Surface Mounted Pressure Sensors
Milled PCB isolation slots and controlled solder standoff heights decouple surface mount pressure sensors from assembly flexure and thermal board strain.
Shore Hardness
Material Property
Indentation resistance testing quantifies the relative hardness of elastomers, plastics, and soft metals. Material datasheets specify shore hardness to classify the stiffness and load-bearing capacity of synthetic rubber seals and gaskets. This property is measured using a durometer, which applies a spring-loaded force to a standardized indentor.
Measurement Scale
Two primary scales, designated as Shore A for flexible rubbers and Shore D for rigid polymers, are used depending on material stiffness. Measured shore hardness values range from zero to one hundred, where higher numbers indicate greater resistance to indentation. The measurement is conducted at a reference temperature because polymer stiffness varies with temperature.
Calibration Protocol
Metrological traceability for durometers is established by calibrating the spring force and the indentor geometry against primary standards. Technicians verify the shore hardness of test blocks to confirm that the instrument reads accurately across the full scale. Handheld measurements are prone to operator force variance, so automated bench-mounted stands are preferred for high-precision testing.
Field Behavior
In operational environments, hardness shifts can occur due to chemical swelling, thermal aging, or plasticizer extraction. Although shore hardness does not directly predict tensile strength or compression set, it remains a critical quality control parameter during material receiving inspections. Suppliers must provide a certificate of compliance demonstrating that each batch of molded parts falls within the specified tolerance band.
This initial check prevents the assembly of overly soft or excessively brittle seals that could lead to immediate pressure loss and joint failure under mechanical stress.