Locally bendable solid plates were manufactured in a single 3D-printing operation, using a single material, i.e., short carbon fiber reinforced plastic (CFRP). The locally bendable CFRP plates included solid and bendable parts, which were connected seamlessly using double-stepped lap configuration. A parallel cross shape structure and 100% infill structure was adopted for the bendable and solid parts, respectively. The bendability could be controlled by varying the girder angle of the parallel cross shape structure. The bending stiffness was reduced to nearly 98% compared to that of the solid plate. The cyclic bending tests indicated that the locally bendable CFRP plate underwent reversible bending deformation. The bending stiffness decreased by approximately 8–14%. However, visible damage was not observed even after 100 cycles of bending deformation.

Short glass fiber (SGF) reinforced polyamide 6 (PA6) composite is an important thermoplastic engineering plastic with excellent properties such as high toughness, high strength, self-lubrication and corrosion resistance. However, due to the characteristics of difficult to disperse and easy to break of the fibers during processing, the application range of the PA6/SGF composite is limited. An innovative twin-eccentric rotor extruder (TERE), which can generate continuous elongation flow, is applied to fabricate the PA6/SGF composites in different fiber content and rotor speed. The fiber length remains good and the fibers are well dispersed in the polymer matrix so that the residual fibers after burn-off form a network interlock structure. That is, the TERE based on continuous elongational flow not only disperses the glass fibers effectively, but also reduces the fiber breakage. Under the action of elongation flow field, the fiber agglomerates undergo a periodic convergence-divergience effect, which forces the fiber agglomerates to separate from each other and disperse homogeneously in the polymer matrix. Interestingly, the charpy impact strength of the composites prepared by the TERE is about double that prepared by the twin-screw extruder (TSE) at each fiber content, which can be attributed to the more efficient fiber dispersion and longer fiber retention length. The thermal oxygen aging property, fatigue property, and creep property analysis also indicate that the TERE has a better dispersion effect than the TSE, and the fibers retain a longer length in the PA6 matrix, thereby providing more excellent service properties.

Nowadays, the improvement of injection molding technology development research is in great demand due to the limitation of convenient injection molding for structural engineering applications. For injection-molded products, oriented structure is ubiquitous. To promote the formation of oriented structure, exert a positive impact on the final mechanical properties of polymer products, an advanced injection molding process is used to achieve multiple shear melt in this work. Based on our previous work about melt multi-injection molding technology, to investigate the influence about oriented structure of composites attracted by higher shear stress, iPP/MWCNTs and iPP/β-NA composites were studied. Compared to traditional injection-molded samples, the addition of MWCNTs impede the formation of oriented structure. For iPP/β-NA composites, the higher flow shear stress inside the mold wall increase the overall crystallinity but restrain the growth of β-crystal.

In recent years, researchers are paying more attention to high efficiency, high process stability and eco-friendly nanofiber fabrication techniques. Among all of the nanofiber fabrication methods, electrospinning including solution electrospinning and melt electrospinning is the most promising method for nanofiber mass production. Compared to solution electrospinning, melt electrospinning could be applied in many areas such as tissue engineering and wound dressings due to the absence of any toxic solvent involvement. Capillary melt electrospinning generates only one jet with low efficiency. Hence, we have proposed polymer melt differential electrospinning (PMDES) method, which could produce multiple jets with smallest interjet distance of 1.1 mm from an umbrella shape spinneret, thus improving the production efficiency significantly. Many techniques such as material modification, suction wind, and multistage electric field were proposed to refine the fibers and nanofibers with average diameter of about 300 nm were obtained. Scale up production line of PMDES with capacity of 300–600 g/h was established by arraying umbrella shape spinnerets. PMDES is a promising technology to meet the requirements of nanofiber production in commercialization.

Compared with the traditional three-platen injection molding machine, the two-platen injection molding machine has many potential advantages such as space and material saving, uniform clamping force, etc. Internal circulation clamping system is the key to realize energy-saving and high speed clamping for small and medium types of two-platen injection molding machines. This paper presented an internal circulation clamping system with supplementary volume. Compared with the other internal circulation clamping systems, the new system with supplementary volume could not only confirm the uniform tension force on tie bars for dramatic increase of service life but also improve energy-saving. In order to estimate the properties of the new system, the models of two different hydraulic clamping systems were established by using AMESim. The displacement of the moving platen, the pressure of the clamping cylinder, and the energy consumption of the hydraulic clamping system were all calculated and analyzed.

Here, the internal structure and mechanical properties of the hydroxyapatite/polycaprolactone scaffolds, prepared by fused deposition modeling (FDM) technique, were explored. Using hydroxyapatite (HA) and polycaprolactone (PCL) as raw materials, nano-HA/PCL and micro-HA/PCL that composite with 20 wt% HA were prepared by melt blending technology, and HA/PCL composite tissue engineering scaffolds were prepared by self-developed melt differential FDM 3D printer. From the observation under microscope, it was found that the prepared nano-HA/PCL and micro-HA/PCL tissue engineering scaffolds have uniformly distributed and interconnected nearly rectangular pores. By observing the cross-sectional view of the nano-HA/PCL scaffold and the micro-HA/PCL scaffold, it is known that the HA particles in the nano-HA/PCL scaffold are evenly distributed and the HA particles in the micro-HA/PCL scaffold are agglomerated, which attribute nano-HA/PCL scaffolds with higher tensile strength and flexural strength than the micro-HA/PCL scaffolds. The tensile strength and flexural strength of the nano-HA/PCL specimens were 23.29 MPa and 21.39 MPa, respectively, which were 26.0% and 33.1% higher than those of the pure PCL specimens. Therefore, the bioactive nano-HA/PCL composite scaffolds prepared by melt differential FDM 3D printers should have broader application prospects in bone tissue engineering.