Analysis of printing parameters for metal additive manufactured parts through Direct Ink Writing process

Direct Ink Writing is an Additive Manufacturing process in which a metal ink is continuously extruded to built-up a green metal part. Therefore, a debinding and sintering process is required to obtain the final metal part. This thermal process produces a shrinkage of the green printed part according to several material and printing parameters. In this paper, the influence of printing process planning on the width of printed rods for a copper ink is analyzed by means of a Design of Experiments procedure to optimize the printing and equipment parameters and characterize the shrinkage after the sintering processPeer ReviewedPostprint (published version

Mod silver metallization: Screen printing and ink-jet printing

Basic material efforts have proven to be very successful. Adherent and conductive films were achieved. A silver neodecanoate/bismuth 2-ethylhexanoate mixture has given the best results in both single and double layer applications. Another effort is continuing to examine the feasibility of applying metallo-organic deposition films by use of an ink jet printer. Direct line writing would result in a saving of process time and materials. So far, some well defined lines have been printed

Pervasive liquid metal direct writing electronics with roller-ball pen

A roller-ball pen enabled direct writing electronics via room temperature liquid metal ink was proposed. With the rolling to print mechanism, the metallic inks were smoothly written on flexible polymer substrate to form conductive tracks and electronic devices. The contact angle analyzer and scanning electron microscope were implemented to probe the inner property of the obtained electronics. An ever high writing resolution with line width and thickness as 200{\mu}m and 80{\mu}m, respectively was realized. Further, with the administration of external writing pressure, GaIn24.5 droplets embody increasing wettability on polymer which demonstrates the pervasive adaptability of the roller-ball pen electronics

Analysis of Writing Inks on Paper Using Direct Analysis in Real Time Mass Spectrometry

Ink analysis is central to questioned document examination. We applied direct analysis in real time mass spectrometry (DART MS) to ballpoint, gel, and fluid writing ink analysis. DART MS acquires the mass spectrum of an ink while it is still on a document without altering the appearance of the document. Spectra were acquired from ink on a variety of papers, and the spectrum of the blank paper could be subtracted out to produce a cleanly isolated ink spectrum in most cases. Only certain heavy or heavily processed papers interfered. The time since an ink is written on paper has a large effect on its spectrum. DART spectra change radically during the first few months after an ink is written as the more volatile components evaporate, but the spectra stabilize after that. A library-search study involving 166 well-aged inks assessed the ability to identify inks from their DART spectra. The aggregate success rate was 92%

Differentiating Writing Inks Using Direct Analysis in Real Time Mass Spectrometry

Writing ink analysis is used in establishing document authenticity and the sources and relative ages of written entries. Most analytical methods require removing samples or visibly altering the document. Nondestructive, in situ analysis of writing inks on paper without visible alteration is possible using mass spectrometry with a new ion source called Direct Analysis in Real Time. Forty-three different black and blue ballpoint, black fluid, and black gel inks were examined. Both dyes and persistent but thermally labile components of the inks contribute to the mass spectra, principally as protonated molecules [M1H]1. Numerous ink components were identified from the spectra. The spectra were placed in a searchable library, which was then challenged with two spectra from each of the 43 inks. The best match for each of the challenge spectra was correct for all but one ink, which matched with a very similar ink by the same manufacturer

The Types Of Corrective Feedback Implemented By The Teacher In Teaching Writing Descriptive Text To The Second Year Students Of SMP N 2 Baturetno

This study is aimed at describing: 1) the types of the corrective teacher feedback used in teaching descriptive text, 2) the student’s response of the feedback given by the teacher in teaching writing descriptive text. In achieving the objectives, the researcher used descriptive qualitative as the approach to collect and analyze the data. The research was held in SMP N 2Baturetno. The research took 30 students of the second year students as the subject of the study. The writer get the data of the research from event, informants, and document. The techniques of collecting data are the observation and interview about the writing teaching- learning process. The result of the analysis shows that the teacher used three types of corrective feedback, namely feedback on content (positive feedback), feedback on form (negative feedback) and the use of red ink and black ink in corrective feedback. The writer can conclude, when the teacher gives direct feedback to the students make easily to understand the learning and they can know what their mistakes. They said that the feedback type applied by the teacher in the teaching writing descriptive makes them easy to write and they can identify and correct the errors. The teacher also used of ink color to correction the learning. In the observation, the teacher uses the redink when she correct students work.In teacher corrective feedback, students can know and correct the errors after it is corrected by the teacher. Keywords: teacher corrective feedback type, descriptive tex

Thermoresponsive polymer micropatterns fabricated by dip-pen nanolithography for a highly controllable substrate with potential cellular applications

We report a novel approach for patterning thermoresponsive hydrogels based on N,N-diethylacrylamide (DEAAm) and bifunctional Jeffamine ED-600 by dip-pen nanolithography (DPN). The direct writing of micron-sized thermoresponsive polymer spots was achieved with efficient control over feature size. A Jeffamine-based ink prepared through the combination of organic polymers, such as DEAAm, in an inorganic silica network was used to print thermosensitive arrays on a thiol-silanised silicon oxide substrate. The use of a Jeffamine hydrogel, acting as a carrier matrix, allowed a reduction in the evaporation of ink molecules with high volatility, such as DEAAm, and facilitated the transfer of ink from tip to substrate. The thermoresponsive behaviour of polymer arrays which swell/de-swell in aqueous solution in response to a change in temperature was successfully characterised by atomic force microscopy (AFM) and Raman spectroscopy: a thermally-induced change in height and hydration state was observed, respectively. Finally, we demonstrate that cells can adhere to and interact with these dynamic features and exhibit a change in behaviour when cultured on the substrates above and below the transition temperature of the Jeffamine/DEAAm thermoresponsive hydrogels. This demonstrates the potential of these micropatterned hydrogels to act as a controllable surface for cell growth

Hybrid Manufacturing: Integrating Direct Write and Stereolithography

A commercial stereolithography (SL) machine was modified to integrate fluid dispensing or direct-write (DW) technology with SL in an integrated manufacturing environment for automated and efficient hybrid manufacturing of complex electrical devices, combining threedimensional (3D) electrical circuitry with SL-manufactured parts. The modified SL system operates similarly to a commercially available machine, although build interrupts were used to stop and start the SL build while depositing fluid using the DW system. An additional linear encoder was attached to the SL platform z-stage and used to maintain accurate part registration during the SL and DW build processes. Individual STL files were required as part of the manufacturing process plan. The DW system employed a three-axis translation mechanism that was integrated with the commercial SL machine. Registration between the SL part, SL laser and the DW nozzle was maintained through the use of 0.025-inch diameter cylindrical reference holes manufactured in the part during SL. After depositing conductive ink using DW, the SL laser was commanded to trace the profile until the ink was cured. The current system allows for easy exchange between SL and DW in order to manufacture fully functional 3D electrical circuits and structures in a semi-automated environment. To demonstrate the manufacturing capabilities, the hybrid SL/DW setup was used to make a simple multi-layer SL part with embedded circuitry. This hybrid system is not intended to function as a commercial system, it is intended for experimental demonstration only. This hybrid SL/DW system has the potential for manufacturing fully functional electromechanical devices that are more compact, less expensive, and more reliable than their conventional predecessors, and work is ongoing in order to fully automate the current system.Mechanical Engineerin