Rapid Prototyping(RP) is an efficient method for rapid design verification and trial manufacturing. The materials being used, however, have been limited mainly to non-functional materials such as photopolymer, plastics, paper, etc. The Direct Metal Prototyping(DMP) allows the manufacturing of three-dimensional metallic parts using metal powders directly from the CAD data. Laser power, scanning speed, and amount of offset are important variables of the process.
The objective of this study is to obtain the design data for laser power and scanning speed to bond metal powders effectively using the finite element method. To obtain the design values, a numerical analysis considering two-dimensional heat transfer on the sintering of metal powder layers of the process was performed. The laser beam has been modeled to have directionality in its heat flux distribution, i.e.; in the scanning direction a Gaussian beam mode distribution has been assumed and in the thickness direction a square beam mode distribution. The three-dimensional irregular distribution of metal powders of the powder layer is idealized as two-dimensional distribution in which metal powders are located regularly and periodically on the plate.
In this study the design values of laser power vs scanning speed have been obtained. Temperature distribution and temperature variation of the powder layers with respect to time have been predicted. The computed design data will be useful in determining the initial conditions of the process.
