Study On The Process Parameters Control Of Plasma Arc Cutting Variable-thickness Plates

Plasma arc cutting plays a significant role for its traits such as the faster cutting velocity, the smooth cutting surface, the easily setting condition, the application fitting for automatic operation. In actual production there are lot of variable thickness panels cutting, the cutting quality will be unstable if process parameters are set according to the way cutting ordinary plates, which will increase difficulty of follow-up procedure.Plasma arc cutting is a physical process which utilize high temperature to heat materials and high speed flow to blow melted metal, cutting quality is directly influenced by arc power and arc force. When the change takes pace in the size of geometry of work piece, the arc power and arc force should change with it. There are a lot of factors that influence the arc power and arc force. These factors include cutting voltage, cutting current, pressure and runoff of air, tungsten setback, nozzle diameter and cutting speed. To analyze and know the rules above-mentioned process parameters influence the quality of plasma arc cutting is the foundation and premise to adjust the optimum process parameters of plasma arc cutting.This article will proceed discuss the influence of mechanical properties on cutting quality from two aspects. The first step is to change cutting speed according to the thickness of work piece, which means to change the absorbed heat of unit. The second step is to change the arc current or the arc voltage, which means to change inputting power. It will be the focus of this article to discuss the adjustment of cutting speed and its implementation method.In accordance with a two-zone approximation of the arc column, a model has been developed to study the properties of plasma arc cutting process. The results of the pressure at the nozzle, arc radius, arc voltage, arc power, arc force exit as a function of arc current have been obtained for a range of operating conditions. It provides the theoretical foundation to adjust the arc process parameters of plasma arc cutting rationally in order to adjust the arc power.According to the equation of the heat conduction a plasma arc cutting mathematics model is founded, this article deduces a temperature distribution by solving the model. By switching temperature field formula arc power absorbed for cutting can be obtained with melting point of material. Contacting the phase transformation enthalpy of material with heat-conduction equation, an appropriate cutting speed can be then predicted in plasma arc cutting.A modern manufacturing system should have the capability to meet consumer's various demands to new products within a certain designated time. Also, it should be able to accommodate the rapid development of computer technologies. In this paper, a modular and object-oriented approach for the PC-based open plasma arc cutting control system is investigated. In addition, the corresponding methods of anti-interference are described according to property of plasma arc cutting.In the finality of this article an experiment study about plasma arc cutting variable-thickness plate is introduced. According to the above-mentioned technique projectabout simple NC system for plasma arc cutting, an experimental equipment based on open-loop control is made. In the experiment different samples were cut using plasma, and the rules of cutting dap, cutting residue and height of chamfer affected by cutting speed is analyzed. The result demonstrated that the way of adjusting cutting speed is obtained.Acted as a reference, the research above- involved will promote the development of the technology of plasma arc cutting variable-thickness plate, extend the applications of plasma arc cutting, and development three-dimensional plasma arc cutting finally.