Many processing parameters can be adjusted to optimize the fused filament fabrication (FFF) process, a popular and widely used additive manufacturing techniques for plastic materials. Among those easily adjusted parameters are the nozzle temperature, printing speed, raster orientation, and layer thicknesses. Using poly(ether ether ketone) (PEEK) as the base material, a design of experiments analysis was performed on the main FFF parameters. A response surface methodology was applied to analyze the results and to maximize the output responses. Results have shown that the nozzle temperature is the most influential parameter on tensile properties and the crystallinity degree of printed PEEK by FFF process. Parts produced with optimized FFF parameters were then subjected to an annealing treatment to induce a relaxation of residual stress and to enhance crystallinity. The best properties for 3D printed PEEK parts were achieved with annealed parts prepared at 400°C with a printing speed of 30 mm/s, 0.15 mm layer thickness and raster orientation of [0°/15°/−15°]. The resulting parts have mechanical properties comparable to those of injected PEEK.

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Inventive Design (ID) methodology has been developed in four main phases, from initial situation analysis to solution concept, in order to overcome TRIZ limitations. However, this methodology needs to optimize its performance, because it takes a lot of time to obtain the best solution concepts. In addition, the ability of ID to give the best result depends on individual knowledge and experience of designer, and correctness of initial situation analysis. The proposed methodology in this article uses a collection of tools and combines a long-term vision for continuous improvement. This improvement method focuses on removing the non-value added activities during the process and maximizing the quality of the results. Integration of this proposed methodology with ID framework will eliminate the wastes, which occur in different phases of ID method and increase its overall efficiency and agility.

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Optimal conditions for milling carbon/epoxy composite material were established by response surface methodology. The combination of cutting parameters such as cutting speed (Vc) and chip thickness (h) was set at various design points of a central composite design. Significant regression models describing the changes of vibration level, delamination of composite, cutting force, workpiece temperature were developed with the coefficient of determination greater than 0.90. Results suggested that beyond a threshold of vibration, the occurrence of delamination is regular. Vibration criterion was defined from the observations of the workpiece according to the delamination defect. The optimum milling conditions were graphically represented using design contour plots. The best combination of process variables was found, according to the cutting conditions. This new technique should help the operator to select the optimum cutting conditions such as cutting speed and feed rate (chip thickness) in order to avoid damage to the carbon/epoxy composite material T800S/M21 and increase machining productivity.