Whether or not aqueous cleaning fluids negatively impact the sensitivity of precision sensors is not a definitive answer. Rather, it depends on the compatibility of the cleaning fluid's characteristics, the sensor's structural materials, and the cleaning process. From the perspective of the cleaning fluid itself, its composition is a key factor. Aqueous cleaning fluids typically contain surfactants, corrosion inhibitors, solvents, and a small amount of additives. If the surfactant is poorly selected or the residual amount is too high, it can form a film on the sensor's sensitive components. This film can hinder contact between the sensor and the object being detected or hinder signal transmission. For example, in precision optical sensors, residual cleaning fluid components on the lens or photosensitive element can affect light transmittance or reception accuracy, indirectly reducing sensitivity. For sensors that rely on electrical signal conversion, residual surfactants with a certain degree of conductivity can interfere with the electrical signal between electrodes, leading to skewed measurement data.
The pH value of the aqueous cleaning fluid is also crucial. Strongly acidic or alkaline cleaning fluids can corrode the sensor's metal electrodes, ceramic substrate, or specialized coatings. For example, the metal strain gauges of some pressure sensors can suffer from even slight corrosion, causing a change in resistance, directly decreasing sensitivity or even leading to sensor failure.
The inherent characteristics of precision sensors also determine their tolerance to cleaning processes. Different types of precision sensors have vastly different structures and core materials. For example, MEMS (micro-electromechanical systems) sensors are tiny and complex internally, with numerous tiny gaps and fragile mechanical components. If the cleaning fluid is too permeable, it may seep into these gaps and be difficult to completely remove. Residual liquid can cause internal components to stick or oxidize during subsequent use, affecting mechanical precision and reducing sensitivity. Gas sensors typically have a special sensitive membrane that is extremely chemically sensitive. If certain components in the aqueous cleaning fluid can dissolve or damage the membrane, the sensor will be unable to properly detect the target gas, significantly reducing sensitivity. Some temperature sensors use thermistors as their sensing elements. If the cleaning fluid contains substances that react with the resistor material, even if there is no noticeable change in appearance after cleaning, it may alter the thermistor's temperature coefficient, resulting in sensitivity shift.
The standardization of cleaning procedures can also affect sensor sensitivity. Regarding cleaning methods, if ultrasonic cleaning is performed with an aqueous cleaning fluid, excessive ultrasonic power or prolonged cleaning time may cause physical damage to the sensor's microstructures. For example, the cantilever beam within an accelerometer can undergo minute deformation due to the intense ultrasonic vibrations, disrupting its mechanical equilibrium and leading to irreversible changes in sensitivity.
Post-cleaning rinsing and drying are also crucial. If rinsing is not thorough, residual components in the cleaning fluid can gradually accumulate on or within the sensor, potentially causing chronic corrosion or electrical performance interference over time. Incomplete drying can also lead to residual moisture. For some moisture-sensitive sensors, residual moisture can accelerate electrode oxidation or create microscopic leakage paths between circuits, affecting signal stability and sensitivity. Furthermore, temperature control during the cleaning process is crucial. If the cleaning fluid temperature is too high, it may exceed the tolerance range of certain sensor materials. For example, components made of certain polymer materials may soften and deform, indirectly affecting the sensor's structural accuracy and sensitivity.
Whether using aqueous cleaning fluid for precision electronics cleaning affects the sensitivity of precision sensors needs to be determined based on the specific circumstances. To avoid adverse effects, it is usually necessary to conduct compatibility testing between the sensor material and the cleaning fluid in advance, select a specialized aqueous cleaning fluid with mild ingredients and low residue, and strictly control the cleaning parameters and subsequent processing procedures to ensure effective cleaning while protecting the sensitivity of the precision sensor.
