The load cell consists of one or more elastomers that can deform after being stressed, and a bridge circuit (such as Wheatstone bridge) that can sense the strain gauge, and can fix the strain gauges. The load cell is composed of three parts, which are adhered to the elastomer and can conduct the strain variable and the sealant for protecting the electronic circuit.

Chinese name: load cell

Material: aluminum alloy, alloy steel and stainless steel

Material characteristics: uniform deformation and deformation recovery, anti-corrosion performance

Influencing factors: creep of the elastomer and sensor temperature

work process

After being subjected to an external force, the strain gauge attached to the elastomer is deformed to cause a resistance change, and the resistance change causes the composed Wheatstone bridge to be out of balance to output a power electrical signal that changes linearly proportional to the external force.

material

Elastomeric material

The force sensor elastomer material is generally made of metal material. Most of the materials that can be used are aluminum alloy, alloy steel and stainless steel. The alloy material has rigidity to ensure uniform deformation and deformation recovery, and good weathering and corrosion resistance. The main requirement of the elastomer is to be able to accurately transmit the force information and maintain the deformation consistency and complete resetting under the same force.

Strain gauge and resistive component materials

The composition of the resistance strain gauge is complex, and it is a composite product. The combination of the strain gauge substrate and the strained copper is ever-changing. According to its strain requirements, there are currently nearly a thousand products. Generally, the substrate is made of a polymer film material, and the strain material is high-purity constantan. The Constantan on the substrate is optically treated to etch different resistance-deformed resistance wires. Therefore, the quality of the strain gauge is not only related to the material quality of the substrate and the purity of the composite metal, but also related to the composite process, etching technology and process, etching chemical materials and post-treatment processes and materials.

Patch adhesive material

The adhesive for strain gauge patch mainly uses two-component polymer epoxy adhesive. The properties of polymer chemical products are closely related to the physical and chemical indexes of each component, such as purity, molecular chain structure and size. , storage time, composition ratio, molecular modification, mixing method, mixing and curing time, curing time, curing temperature, additives and percentage.

Sealant material

In the initial stage of the load cell with insufficient welding technology and equipment, a special silicone rubber sealant series is used. Silicone rubber has long-term chemical stability, so it has excellent properties such as anti-corrosion, moisture-proof, aging-resistant, and insulation. It has long been the first choice for all sealants.

Force sensor wire material

The wire is still part of the load cell. The metal material of the force sensor wire is due to the difference in quality of the household electrical wires. After all, the wire is the path for bridge power supply, signal output, and long-line excitation voltage compensation. The silver-plated wire is definitely better than the copper wire. The copper wire is definitely better than the aluminum wire. The effect is self-evident.

With the increasing interference of various high frequency, radio waves, etc., the excellent shielding of the load cell is also an important method to protect the signal stability. In addition, environmental erosion, pests, fire retardant, etc. also require the material of the sensor protective layer to prevent corrosion and fire, and even need to use armor protection, casing protection and other methods.

Wire sealing material and method

Each component of the load cell affects the final technical performance of the sensor. Some load cells only use a simple and fixed way to avoid the movement of the sensor wires and damage the electronic circuit of the sensor. Some load cells with short conduction distances are even only Rely on the rubber seal. However, a large-volume, heavy-weight load cell, if there is no proper wire fixing or sealing, is the bottleneck that the load cell is most prone to failure. In particular, when the sealing head is fixed, the material and fastening strength of the fastener will also affect the final technical performance of the load cell. Observers have found that it is rare to use fasteners to install sealing adhesives, which avoids residual stresses caused by fastening forces and does not cause leakage due to insufficient fastening force.

Shenzhen Juli Sensing Technology Co., Ltd. is a professional manufacturer of high quality and high precision sensors. The main products include load cell, micro pull/pressure sensor, pull rod type tension and pressure sensor, S type tension and pressure sensor, ring sensor, column sensor, shaft pin type sensor, weighing type sensor, three-dimensional force and other multi-axis force sensors. Static dynamic torque sensors, micro-displacement sensors, pressure transmitters (hydraulic sensors), transmitters/amplifiers, control instruments, and hand-held instruments have more than 100 kinds of force control products, and have obtained a number of national patents;

Products are widely used in more than 10 new and intelligent high-end areas, including industrial automation production lines, robotics, machinery manufacturing, medical, textile, automotive, metallurgy and transportation;

Product technology continues to innovate and new product research and development capabilities.