Production Process And Technical Points Of Epoxy Resin Casing

The resin mixing process adopts a vacuum stirring process. Add the resin and curing agent to the stirring kettle in proportion, stir at a low speed of 60 rpm for 10 minutes, and vacuum to -0.08MPa to eliminate bubbles. When adding fillers, feed them three times, with an interval of 3 minutes each time to avoid agglomeration. The mixed resin must be used up within 30 minutes. If the viscosity increases beyond the time, it must be discarded.
The impregnation process is completed in two times. For the first impregnation, the prefabricated epoxy bushing is vertically immersed in the resin liquid for 3-5 seconds. After being taken out, it is left to stand for 2 minutes to allow excess resin to drip naturally. The second impregnation adopts pressurized infiltration, which is maintained at a pressure of 0.3MPa for 10 seconds to ensure that the fiber gaps are fully filled. After impregnation, epoxy resin bushing is hung in a constant temperature zone, and the temperature is maintained at 35℃ to prevent sagging.
The step-by-step heating method is used in the curing stage. In the first stage, the temperature is preheated at 60℃ for 2 hours to make the resin gel initially. In the second stage, the temperature is raised to 100℃ at a rate of 2℃/min and maintained for 4 hours to complete the main curing. In the third stage, the temperature is post-cured at 130℃ for 2 hours to increase the crosslinking density. The heating process must be uniform, and the temperature difference should not exceed ±3℃ to avoid local stress cracking.
Post-processing includes demoulding, trimming and surface treatment. When demoulding, compressed air is blown in from the mold injection hole, and the separation force is controlled below 5N/cm². Diamond grinding wheel is used for trimming to grind the flash, and the chamfer radius is not less than 0.5mm. The arc-resistant coating is sprayed on the surface, and the coating is filtered by a 180-mesh filter. The spray thickness is 50±5μm and dried at 80℃ for 1 hour.