Evaluating Viscoelastic Creep and Tactile Probe Indentation during Elastomer Metrology
Tactile metrology of elastomers requires sub-0.02 N trigger forces and zero-load extrapolation to prevent viscoelastic creep from corrupting part dimensions.
Tactile Probe Indentation
Meaning
Physical displacements occur when the mechanical contact force of a measurement sensor deforms the surface of a soft material. Quality control technicians monitor tactile probe indentation to prevent dimensional errors when inspecting soft polymer gaskets. The mechanical contact of the sensor can create a temporary or permanent crater in compliant materials, which corrupts the measured profile.
Deflection Mechanism
Sensor contact during coordinate inspection runs can create a temporary or permanent crater in compliant materials. Pliable polymers experience local deformation under the spring-loaded force of the measurement stylus. The resulting deflection registers a false dimension that is smaller than the actual part size.
This error leads to incorrect failures during the quality inspection phase.
Measurement Deviation
Surface damage changes the local dimensions of the part and introduces systematic error into the recorded profile. The magnitude of the displacement depends on both the contact force and the elasticity of the material being tested. Harder materials show negligible deflection, while soft elastomers deform easily.
This variance makes it difficult to establish a standard offset value for all parts. Inspectors must calculate the expected compression based on the material properties of the sample and subtract this value from the measurement.
Material Selection
Engineering choices favor low-force sensors or non-contact optical instruments when measuring delicate elastomer components. Utilizing the correct sensor prevents damage to the surface of high-precision parts. This practice maintains the accuracy and cosmetic quality of the product.