Study On The Preparation And Properties Of Substrate Of Load Cell Strain Gage

Stain gage load cells are diffusely used in the mechanical measurements with high precision. At present, the manufacture of high-precision load cell in our country are relatively backward which restrict the development of high-precision sensors. To satisfy the high-precision sensors,operating requirement of the high property substrate, the article researched two kinds of film substrate. One film substrate was made by glass fiber(GF) reinforced epoxy resin composites, another kind of film substrate was made by glass fiber(GF) and Mica reinforced epoxy resin composites. Then the article studied the performance of the substrate. The main results are summarized as follows:Firstly, the epoxy resin, polysulfone and reinforcement were mixed with each other in the twin-screw extruder. To examine its mixing effect under the different rotational speed, optical microscope was used to have a test. The result showed that under the speed of 30r/min, the composites was mixed well-distributed.Secondly, the curing process of pure epoxy resin and epoxy film substrate with different reinforcement contents were investigated with Differential Scanning Calorimetry(DSC). Using the constant velocity to rise the temperature, c uring curve of different DDS proportions can be obtained: When the quality of the DDS in the epoxy resin is 12%, The heat Han is the largest. Using DSC in the inconstant temperature to scanning epoxy resin mixed polysulfone, and curing temperature can be obtained by T-b extrapolation: gelation temperature was 90 ℃, curing temperature was 130℃, post cuing temperature was 160℃. To get the curing temperature of glass fiber(GF) and Mica reinforced epoxy resin composites by the same way: gelation temperature was 80℃, curing temperature was 130℃, post cuing temperature was 180℃.Under the different curing time, the DSC curves of different proportion shows: when gelation temperature kept 1h, curing temperature kept 2h, post cuing temperature kept 2h, epoxy resin film of different proportions can be cured completed.Finally, the thermal properties, creep and the dynamic mechnical properties of epoxy film substrate with different reinforcement contents were tested with DMA and DSC, and the main performance parameters of the epoxy film substrate with different reinforcement contents was tested after the damp heat aging. The result showed that with the reinforcement adding to the epoxy film substrate, Tg was increased in some degree. The result showed that the Tg temperature of 10%GF and 10%Mica reinforced epoxy resin was the highest which increased 31 ℃. compared with the pure epoxy resin.Under low temperature, creep of each substrate was quite small, with temperature increasing, the creep resistance of 30%GF reinforced epoxy had a minimum improvement, but its Initial storage modulus was maximum reached 4248 MPa. Damp heat aging experiment shows: 30%GF reinforced epoxy has a minimum water absorption rate, and the best property for resisting the damp heat aging, and its change of Tg before and after the damp heat aging experiment was decreased a bit, but the storage modulus dropped a lot.