The working principle of tension/compression sensors is based on the piezoresistive or strain effect of metallic materials. When an external force is applied to the elastic element of the sensor, the elastic element deforms, and the resistance strain gauge attached to its surface deforms accordingly, resulting in a change in resistance. By measuring this change in resistance and converting it into a voltage signal output using a Wheatstone bridge, the magnitude of the applied tension or compression can be accurately calculated. This process of converting the physical quantity of force into an electrical signal is the foundation for the accurate measurement achieved by tension/compression sensors.
Structurally, tension/compression sensors mainly consist of an elastic sensing element, a resistance strain gauge, a measuring circuit, and a housing. The design and material selection of the elastic sensing element determine the sensor's measurement range and accuracy; different shapes and materials of elastic elements are suitable for different application scenarios. Based on their measurement principles, tension/compression sensors can be categorized into several types, including resistance strain gauge, capacitive, and inductive. Among these, resistance strain gauge sensors dominate the market due to their mature technology, high accuracy, and low cost.
Resistance strain gauge sensors are widely used in electronic scales. Whether in everyday supermarket scales or large industrial weighbridges, resistance strain gauge sensors are core components. When an object is placed on the weighing platform, pressure is transmitted through an elastic element, causing the resistance strain gauge attached to it to deform, thus changing the resistance value. This change is then converted into a corresponding weight value by the measuring circuit and displayed. Due to its low cost and mature technology, it can meet the accuracy and stability requirements of most weighing scenarios.
Capacitive compressive strength sensors are commonly used in precision measurement applications that are sensitive to minute force changes, such as pressure monitoring in semiconductor chip manufacturing. In the photolithography process of chip manufacturing, it is necessary to precisely control the pressure of the pressure head on the silicon wafer within the photolithography equipment. Capacitive compressive strength sensors, with their high sensitivity, can accurately sense extremely small pressure changes and convert them into capacitance changes for measurement, ensuring the accuracy and stability of the chip manufacturing process and preventing chip quality problems caused by improper pressure.
Inductive tensile and compressive strength sensors have important applications in the inspection of metal parts on automated production lines. For example, on automotive parts production lines, for the inspection of the dimensional accuracy and assembly quality of some critical metal parts, inductive tensile and compressive strength sensors can determine whether there are defects in the parts or whether the assembly is in place by detecting the change in inductance caused by the metal parts under force. When a part has problems such as cracks or deformation, its change in inductance after being subjected to force is different from that of a normal part. The sensor can detect this in time and issue an alarm, ensuring the normal operation of the production line and product quality.
