Design And Simulation Of The NC Plasma Bevel-cutting Mechanism

The thermal cutting of steel plate is widely used in machine manufacturing to improve its production efficiency and manufacture quality, and now NC (numerical control) cutting machine is playing a more important role. For the groove part, at present, direct bevel cutting technology has been used in NC cutting machine in developed country. The mainly used function part is rotary cutting torch. Cutting torch angle can be modulated automatically to achieve the hardware precision, but there are also some problems to be solved. This kind of machine is too big and special equipment must be used for solving the problem of how the line is loosed and tightened while revolving. The working condition of antitwist bearing is also bad and the life is short. If the bearing is invalid, it may cause very serious safe problem.In order to overcome the above shortcomings, this thesis designs a new bevel-cutting mechanism. Firstly, the mathematical model is established. The new machine can cut a taper with its top point fixed. The cutting motion of torch is realized by the composite revolving of the two orthogonal axes. And then, the framework of the mechanism is designed based on the model, using planar parallelogram structure through the cutting motion of the cutting torch composed by the movement of the rotary axis and the linkage. The cutting torch does not have to revolve itself, and correspondingly, the machine does not need the antitwist bearing and the equipment for loosing and tightening the lines. The new machine with light weight not only has significantly simplified framework, but also has lower manufacture cost.In addition, this thesis also simulates the movement of the mechanism by simulation method based on Pro/E software. The design error of the head of linking board in the mechanism δ₁ and the initial position error of the cutting torch δ₂ are selected and compared. The results indicate that the error caused by δ₁ is bigger, but this kind of error only appears in the half of cutting procedure. The error caused by δ₂...