Plasma arc cutting is a fusion cutting process in which a gas constricted arc is employed to produce high temperature, high velocity jet at the workpiece. Even though the plasma arc cutting has been widely used in the industry, very little work has been done on the analysis of the process, especially of the kerf width.
This paper is divided into two sections. The first part is a study on the determination of the kerf width, and the second one is to develop an algorithm required for the CNC-typed automatic cutting machine.
The kerf width was numerically determined by solving the temperature distribution of the base metal under consideration of latent heat. In calculation, it is assumed that the heat intensity has a Gaussian distribution in the transverse direction and is characterized by a exponentially decreasing function in the thickness direction.
A series of the experiments were carried out with AL-alloy to confirm the numerical results. The comparison between theory and experiment shows that the theoretically predicted kerf widths are in good agreement with the experimental ones.
For the combined position and path control of a CNC-typed cutting machine, the Bresenham's algorithm was used to acquire the line and circle interpolation. The velocity can be simultaneously controlled by the overflow of the register in microcomputer and the number of required clocks as in the DDA interpolator. FFT recordings show that the required cutting velocity can be performed accurately by using the microcomputer-controlled system devised in the present study.
