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Electrohydrodynamic-jet (E-jet) printing is an on-demand additive manufacturing method that allows various functional materials to be directly deposited on the target substrate. Many theoretical and experimental results indicate that E-jet has scale effect, and reducing the inner diameter of the nozzle can effectively improve printing resolution. Herein, a method for fabricating SU-8 polymer micro/nanoscale nozzle by oxygen plasma assisted room temperature bonding was proposed. It can prevent channel deformation and blockage caused by excessive bonding temperature. The surface modification parameters of silicon nano-mold were optimized, the influence of hot embossing parameters on the replication precision of nano patterns was investigated, the effect of UV lithography parameters on the micro and nanochannel was analyzed, the relationship between the oxygen plasma treatment parameters on the contact angle of SU-8 was revealed, the influence of bonding pressure on the morphology of the nanochannel was discussed, and the bonding principle at room temperature was deeply analyzed. This method can fabricate SU-8 polymer micro/nanoscale nozzle with low cost and high precision, and provide a new idea for the realization of room temperature bonding to manufacture SU-8 polymer nozzle.

Electrohydrodynamic-jet printing (E-jet printing) is a direct-writing technology for manufacturing micro-nano devices. To further reduce the inner diameter of the nozzle to improve the printing resolution, a large-scale manufacturing method of SU-8 polymer micro/nanoscale nozzle by means of a process combining UV exposure and hot embossing was proposed. To improve the adhesive strength between the UV mask and SU-8, the influence of the oxygen plasma treatment parameters on the water contact angles of the UV mask was analyzed. The effect of hot embossing time and temperature on the replication precision was studied. The influence of UV exposure parameters and thermal bonding parameters on the micro and nanochannel pattern was investigated. The SU-8 polymer nozzles with 188 ± 3 nm wide and 104 ± 2 nm deep nanochannels were successfully fabricated, and the replication precision can reach to 98.5%. The proposed manufacturing method of SU-8 polymer nozzles in this study will significantly advance the research on the transport properties of nanoscale channels in E-jet nozzles and facilitate further advancements in E-jet based applications. [ABSTRACT FROM AUTHOR]

The saw-tooth chip formation is one of the main machining characteristics in cutting of titanium alloys. The numerical simulation of saw-tooth chip formation, however, is still not accurate, since most of these numerical simulation models are based on traditional finite element method, which have difficulties in handling extremely large deformation that always occurs in the cutting process. Furthermore, these models adopt the Johnson–Cook damage constitutive law that is implemented in commercial codes such as ABAQUS® and LS-DYNA® to describe the dynamic mechanical properties of material, but Johnson–Cook damage constitutive law cannot account for the material of behavior due to strain softening and the dynamic recrystallization mechanism that occurs in the cutting process of Ti–6Al–4. Therefore, this work introduces a material constitutive model named hyperbolic tangent (TANH) and an improved smooth particle hydrodynamics method, and then develops an improved cutting model for Ti–6Al–4V titanium alloy through our in-house code to predict saw-tooth chip morphology and cutting forces. When compared to the experiments and Johnson–Cook damage model, the improved cutting model better explains and predicts the shear localized saw-tooth chip deformation as well as cutting forces. [ABSTRACT FROM AUTHOR]