Modeling and Control of Multi Beam Laser Cutting



    Today's laser cutting methods uses an assisted cutting gas to achieve high quality cuts. This cutting process are as follows: The laser beam melts the material and it is blown away by a high gas pressure so that it will not solidity before it leaves the kerf. This technique has proven to give high quality burr free cuts. However, the use of assisting gas has its disadvantaged. First of all it demands a gas source to be placed close to the cutting point and thus demands mechanical parts to follow the cutting beam at all time. Also to ensure that the gas can blow away the molten material in thicker materials a wider kerf needs to be made. Both slows down the cutting speed and makes it less flexible.

    This project will be carried out as a part of the research project: ROBOCUT. The core idea behind ROBOCUT is to use a multi beam laser pattern to create a high evaporation pressure to blow away the molten material. This technique eliminate the need of assisting gas and has the potential to create a much higher pressure down through narrow kerfs than with traditional gas.

    This PhD project will focus on modeling and control of the multi beam laser cutting process. An accurate model is important for two reasons: 1) To design a laser pattern that efficiently will blow away the molten material, and 2) To make an optimal control of the variables involved in the laser cutting process to assure high quality cutting at a high speed.

    This multi-physic modeling task requires the simulation model to include several aspects to simulate the behavior of the melt flow: Modeling of melting and vaporization of the material, heat conduction, convection computation and evaporation pressure.

    Furthermore, the elimination of the need of the assistant gas opens for remote laser cutting. As no mechanical parts needs to follow the laser beam the freedom of movement becomes much larger. This opens for a lot of possibilities but sets much higher demands on the control of the laser cutting process. Therefore a new control strategy are to be developed, during the project, to control the multi beam laser cutting process.

    The project is carried out from 2010-12 to 2013-12 as a PhD project financed by Department of Production and HTF. Supervisor: Morten Kristiansen. (Martin Andersen, Department of Mechanical and Manufacturing Engineering, AAU)
    Effektiv start/slut dato01/12/201001/12/2013