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A novel pellet 3D printer was first developed, and its structure was constructed out of three main parts. The material used in this device was polycaprolactone (PCL), which was praised for its good characteristics in the biomanufacturing and chemical industries. Three essential parameters that had important effects on the diameter of the printed fibers were systematically studied using a L9(34) orthogonal design table. Using the fused deposition modelling (FDM) method, some products were printed with this machine. Results showed that the stepper motor’s speed had the most significant effect on the diameter of the printed fibers. The optimal parameters were, a stepper motor speed of 1.256 mm3 s−1, a nozzle moving speed of 9.6 mm s−1, and 1.1 mm of height between the nozzle and the platform. Defects like gaps, warping, and poor surface quality were found to be related to different combinations of process parameters. By using the developed pellet 3D printer, the pre-step of making filaments can be avoided, which will bring convenience to FDM 3D printing.

Two-dimensional inkjet technology has made great progress in colorful plane printing. However, color printing technology for three-dimensional model is currently only at the exploratory stage; there are few reports on this issue. In this article, a free-form surface-oriented five-axis single-point printing technology with exclusive color nozzle is proposed. The single-point color nozzle consists of four print heads: prints cyan, magenta, yellow, and black pigment. For high-efficiency color printing, each print head prints on the same single point when the color nozzle moves along the surface. The method of color printing along the surface normal direction is proposed as normal direction printing mode. The algorithm of print point generation is introduced, and the path planning method of self-adaptive slicing and self-adaptive printing filling is proposed. In addition, a five-axis single-point printing platform is designed. Experiments are done to demonstrate the feasibility of the printing system.

Purpose Fused filament fabrication (FFF) is a common additive manufacturing method that is widely used owing to its low cost, environmental friendliness and safety. Colour models are needed because of their ability to express more information, but high printing quality and efficiency are difficult to achieve with the existing FFF colour printing methods because of the “inertia” of printing. Inertia refers to the feature of the former colour material remaining in the molten cavity when switching colours in colour FFF printing. The purpose of this paper is to propose a new FFF colour printing method to reduce printing material usage and printing time. Design/methodology/approach A new FFF colour printing method that uses transitioning waste to construct the part is proposed. Based on the freedom of the colour surface model’s interior space, the internal fill and support of the print model are generated using the transitioning waste to reduce printing material usage and printing time and to achieve environmentally friendly colour printing. The modified elite ant system (EAS) algorithm is used to construct and optimize this method based on the colour surface model. Findings A colour printing experiment is performed using a colour-mixing FFF printer platform with a special waste extrusion module. The experimental results show that this method can significantly reduce material and time consumption compared to the commonly used method. The printed part produced by this method also has high surface quality. Originality/value A new FFF colour printing method that uses transitioning waste to construct the part is proposed. Based on the freedom of the colour surface model’s interior space, the internal fill and support of the print model are generated using the transitioning waste to reduce printing material usage and printing time and to achieve environmentally friendly colour printing. The modified EAS algorithm is used to construct and optimize this method based on the colour surface model. A special waste extrusion module is developed.

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