progress in tridimensional (3d) laser forming of stainless steel sheets

Achievement of complex shapes with high dimensional accuracy and precision by forming process is a demanding challenge for scientists and practitioners. Available technologies are numerous, with laser forming being progressively emerging because of limited springback, lack of molds and sophisticated auxiliary equipments. However, laser forming finds limited applications, especially when forming of tridimensional (3d) complex shapes is required. In this case, cost savings are often counterbalanced by the need for troublesome forming strategies. Therefore, traditional alternatives based on mechanical devices are usually preferred to laser systems. In the present work, 3d laser forming of stainless steel sheets by high power diode laser is investigated. In particular, the set of scanning patterns to form domes from flat blanks by simple and easy-to-manage radial paths alone was found. Numerous 3d items were also processed by diode laser to manufacture a number of complex shapes with high flexibility and limited efforts to modify the auxiliary forming equipment. Based on the experimental results and analytical data, the high power diode laser was found able to form arbitrary 3d shapes through the implementation of tailored laser scanning patterns and appropriate settings of the operational parameters

Effect of Industrial Heat Treatment and Barrel Finishing on the Mechanical Performance of Ti6Al4V Processed by Selective Laser Melting

Additive manufacturing is now capable of delivering high-quality, complex-shaped metallic components. The titanium alloy Ti6Al4V is an example of a printable metal being broadly used for advanced structural applications. A sound characterization of static mechanical properties of additively manufactured material is crucial for its proper application, and here specifically for Ti6Al4V. This includes a complete understanding of the influence of postprocess treatment on the material behavior, which has not been reached yet. In the present paper, the postprocess effects of surface finish and heat treatment on the mechanical performance of Ti6Al4V after selective laser melting were investigated. Some samples were subjected to barrel finishing at two different intensities, while different sets of specimens underwent several thermal cycles. As a reference, a control group of specimens was included, which did not undergo any postprocessing. The treatments were selected to be effective and easy to perform, being suitable for real industrial applications. Tensile tests were performed on all the samples, to obtain yield stress, ultimate tensile strength and elongation at fracture. The area reduction of the barrel-finished samples, after being tested, was measured by using a 3D scanner, as a further indication of ductility. Experimental results are reported and discussed, highlighting the effect of postprocessing treatments on the mechanical response. We then propose the optimal postprocessing procedure to enhance ductility without compromising strength, for structures manufactured from Ti6Al4V with selective laser melting

Machining of Composites and Innovative Manufacturing Techniques

Proceedings of ESDA 200

Intricate shape prototypes obtained by FDM

Fused deposition modelling (FDM) is a filament based rapid prototyping system. FDM allows to build the components layer by layer by extruding a semi-molten thermoplastic polymer, thus allowing to overcome common drawbacks of the conventional machining. Complex shapes like curved shell-type structures (skull bones, turbine blades, marine propellers) can be therefore manufactured without the use of any special tools. Further, process parameters are minimally or not influenced by the final shape of the components. Nowadays, the planning of new components design mostly relies on Computer Aided Design (CAD) environments where each curve or surface is approximated by manual or semi-automatic definition of nets of control points. This leads to an intrinsic limit of the modelling capability above all at the early stage of the product development. In this paper an innovative approach to components design and manufacturing is proposed using Wolfram Mathematica platform. It is based on the employment of parametric mathematical formulations to model the component being manufactured. This method is applied to manufacture some intricate shape prototypes. The experimental findings emphasize how significant the decrease in time to market can be, avoiding the use of time consuming procedures typical of the CAD environments