The basic points of the design of jigs and fixtures

1. The clamping method of mechanical parts is 　　a directly aligning and clamping 　　, the efficiency is low, and the alignment accuracy is high; it is suitable for single-piece, small-batch and simple-shaped workpieces. b. Scribing, alignment, and clamping have good versatility, but the efficiency is low, and the accuracy is not high; suitable for single small batch and complex shape castings 2. Three principles of clamping after the parts are positioned in the fixture a. The parts are positioned in the fixture The latter principle of non-movement selects the direction of the clamping force to point to the positioning datum (the first datum), and the magnitude of the clamping force should be sufficient to balance the influence of other forces and prevent the parts from moving during processing. b. The principle of non-deformation after the parts are positioned in the fixture. Under the action of the clamping force, the parts will not be deformed during the machining process that is not allowed by the accuracy. You must select the appropriate clamping position and adjust the pressure plate and the part. Apply proper pressing force to the contact state.　　C. The principle of non-vibration after the parts are positioned in the fixture 　　 to ensure the rigidity of the support and clamping system, the clamping position should be as close as possible to the processing area of u200bu200bthe part to avoid vibration of the part and the clamping system. Generally speaking, for the fixture used for rough machining, choose a larger clamping force, mainly considering the principle of non-movement of the parts, and for the fixture used for finishing, choose a smaller clamping force, mainly considering the non-deformation and non-deformation of the parts. Principle of vibration.