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Industrial manufacturing is confronted with increased cost pressure due to international competition. The use of automation solutions can help to optimally exploit existing potentials and react to market competitors. In particular, increased productivity and shorter cycle times lead to reduced costs and increased capabilities. New manufacturing technologies can also help to achieve an advantage over market competitors. In recent years, additive manufacturing technologies in particular have gained in importance. Laser Powder Bed Fusion (L-PBF) is an additive manufacturing (AM) technology that enables the production of highly complex and individualized metal components. A significant disadvantage of L-PBF is the required post-processing of additive manufactured parts, which is necessary to remove auxiliary structures, separate the workpieces from the substrate plate and obtain high precision as well as low surface roughness. Automation of these post-processes is a crucial factor for increasing productivity and thus for further industrialization of L-PBF. In order to exploit this potential optimally, the level of automation has to be determined. In this paper, a methodology is presented that enables the determination of the level of automation for the additive process chain with L-BPF. The focus is on evaluating the level of automation of individual manufacturing technologies due to consideration of technology-specific requirements and characteristics. The scope of the analysis is not limited to technologies; handling processes are also taken into account. A differentiated evaluation of the level of automation is enabled by the definition of technology-specific and cross-technology sub-tasks.

El contenido de los capítulos 3, 4 y 5 está sujeto a confidencialidad. 251 p., En el presente trabajo de investigación se ha desarrollado una metodología para la mejora del proceso de aporte por láser mediante la modelización del mismo. El problema se ha abordado en diferentes pasos. Primero de todo, se ha desarrollado un cabezal de aporte que cumple con todos los requerimientos del proceso mediante un software comercial de CFD. Posteriormente, se ha fabricado y validado el mismo. Además, con el objetivo de mejorar la eficiencia de la boquilla e incrementar la estabilidad del proceso, se ha desarrollado un sistema novedoso de regulación del caudal del polvo. El cabezal de aporte ha sido empleado satisfactoriamente para la reparación y fabricación de diversas piezas. En lo que respecta a la modelización, se ha desarrollado un modelo que considera los fenómenos fluido-dinámicos que se producen dentro del baño fundido generado por un haz láser. Una vez se ha validado el modelo, se ha empleado para evaluar la importancia de considerar u omitir el movimiento del material fundido. Los resultados obtenidos indican que la influencia del movimiento del material fundido es mínima en el proceso de aporte por láser y pueden ser omitidos sin que ello suponga una pérdida de precisión. Basándose en esta última afirmación, se ha desarrollado un modelo tridimensional que simula el proceso de aporte por láser al completo. Este modelo calcula la transferencia de calor por conducción dentro de la pieza y la geometría del material aportado. Además, en función de los ciclos de calentamiento y enfriamiento que sufre el material, es capaz de predecir las propiedades mecánicas resultantes, tales como dureza, microestructura o la formación de poros.

The melt pool dynamics consideration in the numeric modeling of the Laser Material Deposition (LMD) process can be enormously difficult and expensive, especially if this calculation is not strictly necessary. The increased cost comes mainly from the necessity of considering a higher number of input parameters into the model in addition to the computational cost. Therefore, an analysis of the influence of the melt pool dynamics in a LMD model and its impact on the accuracy is presented. For this purpose, a numeric model that simulates the melt pool fluid-dynamics has been developed and experimentally validated for different situations. After a detailed analysis of the results, an exponential formula based on the response surface methodology (RSM) that quantifies the influence of the fluid-dynamic phenomena inside the melt pool has been obtained. The main conclusion of the present work is that the LMD process can be addresses as a thermal problem without considering the melt pool dynamics and without losing accuracy for a certain window of process parameters, what reduces the computational cost and will allow an easier integration of the model in CAE tools for process simulation.

A new control system for regulating the powder flux during the laser metal deposition process (LMD) has been designed, developed and validated. The powder regulation system is based on a solenoid, which is coupled to the LMD nozzle and controlled by means of a Pulse Width Modulation (PWM) signal. Thanks to this system, the deposited clad height can be regulated depending on the process parameters, what allows obtaining a more homogeneous layer height and results in a more stable process. The material over-height at the beginning of the clad has been completely avoided when the control is applied. The material accumulation in corners where the deposition direction is changed has been also reduced from 0.65mm to 0.35mm. Furthermore, simulations of the nozzle and the powder particle stream have been carried out in order to validate the designed system and analyze the powder particle distribution at the nozzle exit.