Micro-needles finds abundant applications in the field of medicines, nanodevices and as a tool for µ-EDM to study single spark energy. Fabrication of such micro-needles with high accuracy and precision is a challenging task. In this work, an attempt has been made to manufacture a brass rod by micro-turning to a diameter of 100 µm. Effects of cutting speed and feed rate on feed-force, cutting-force, machining-force, surface-roughness, power, and specific cutting force have been studied to optimize the process of fabricating a brass micro-needle with a smoother surface. SEM, EDS, and AFM have been performed to study cutting behavior along with the fracture behavior of fabricated micro-needle. The cutting force behavior was non-linear and was in accordance with the available literature even at micro-level. In addition to this, the fabricated micro-needles were etched using hydrogen peroxide (H₂O₂) to fabricate a sharp-pointed needle having a diameter of ≤ 10 µm. Fabricated µ-turned sharp micro-needles may be further used as a tool to study single spark energy in the µ-EDM process. Additionally, crater depth, diameter, tool wear rate (TWR) and material removal rate (MRR) have been calculated for the single spark of the µ-EDM process using fabricated micro-tool.

A simple synthesis of highly planar extended π‐electron molecules is of particular interest for the development of efficient nonfullerene acceptors in organic solar cells with high light absorption and high mobility. Herein, two small‐molecule acceptors (MPU7 and MPU8) with a diketopyrrolopyrrole core connected to CPTCN end‐capping groups (A₂) via thienylethynylselenophene (MPU7) or thienylethynylthiophene (MPU8) linkers are conceived and synthesized. Planarity of the conjugated skeleton is achieved in both molecules, thanks to the existence of four (Se⋯O or S⋯O) noncovalent, through‐space intramolecular interactions. Both nonfullerene small‐molecule acceptors show broad absorption in the visible and near‐infrared region (up to 930 nm). As a result, the binary solar cells constructed together with a polymer donor (P) display power conversion efficiencies as high as 14.12%. Devices built with MPU7 (containing the selenophene) show better film morphology, electron mobility, and higher efficiency than those containing thiophene (MPU8).

Single point incremental sheet forming (SPISF) technique is an emerging process for die less forming. It has wide applications in many industries viz. automobile and medical bone transplants. Among several key parameters, toolpath planning is one of the critical aspects of SPISF. Also, formability and geometric accuracy have been the two major limitations in SPISF. Spiral and constant incremental toolpaths and their variants have been investigated in detail by several researchers. Fractal-based toolpath planning is also an attempt to improve the process of SPISF. Formability is measured in terms of thickness distribution and maximum forming depth achieved. This paper investigates a fractal geometry-based incremental toolpath (FGBIT) strategy to form a square cup using incremental sheet forming (ISF). Fractal toolpath is a space-filling toolpath which is developed by the fractal geometry theory. A comparison-based study is conducted to observe the benefits of using FGBIT over traditional toolpaths (spiral and constant Z). Better formability, stress, and thickness distribution have been observed by adopting the proposed toolpath strategy. This toolpath strategy is new in its kind and has not been investigated in the metal forming domain. Experiments and simulations are conducted to validate the concept with reasonable accuracy.