The term simulation describes the “reproduction of a system with its dynamic processes in a model capable of experimentation to arrive at findings that can be transferred to reality” (VDI Guideline 3633). Simulations are applied to systems whose complexity makes predictions about their behavior only possible to a limited extent. Further reasons for the transfer into an abstracted surrogate model are cost and safety aspects. At iwb, models have been developed, verified, and validated in various areas of additive manufacturing. Beyond the mere prediction of system behavior, the simulations developed can contribute to process improvement and manufacturing process development.
Process simulation laser beam melting
Particle-based calculation of melt pool geometry and dynamics and resulting local temperature fields are performed using self-consistent heat sources. The results are used in manufacturing for improved process design of filigree or thin-walled component areas and graded material transitions. Furthermore, in the sense of a multiscale simulation, heat source models can be calibrated for the structural simulation, and consequently, their accuracy can be increased.
Structure simulation laser beam melting
Residual stresses and deformations at the component level, caused by the resulting temperature gradients during melting, are calculated in a thermomechanical simulation. In addition, the calculated information is used by the program to generate a distortion-optimized component for the user. Thus, in addition to increasing the process understanding, the developed simulation program makes a so far unique contribution to the manufacturing process development as well as to the support of the process design and avoidance of test manufacturing.
Due to the increased use in series production, the requirements for form, position, and dimensional tolerances are increasing. Warpage compensation is a possible method for minimizing the effects of warpage phenomena inherent in the process to increase product quality. This is intended to expand the possible range of applications for additive manufacturing processes and increase process productivity by reducing scrap and maximizing the use of installation space.
The cause of the warpage depends on the process selected in each case. Whereas in laser sintering, thermal processes are in the foreground, in powder bed-based 3-D printing with a binder, chemical processes such as polymerization processes are primarily responsible for unwanted deformations.
The chosen approach is based on the compensation of deformations caused by warpage already before the construction process. A software tool is used to pre-deform the digital 3D geometry of the component so that the resulting deformations and the warpage caused in the manufacturing process compensate for each other.